пятница, 14 декабря 2007 г.
Honey Helps Problem Wounds: "Medihoney" Is Often More Effective Than Antibiotics
A household remedy millennia old is being reinstated: honey helps the treatment of some wounds better than the most modern antibiotics. For several years now medical experts from the University of Bonn have been clocking up largely positive experience with what is known as medihoney. Even chronic wounds infected with multi-resistant bacteria often healed within a few weeks. In conjunction with colleagues from D�sseldorf, Homburg and Berlin they now want to test the experience gained in a large-scale study, as objective data on the curative properties of honey are thin on the ground. The fact that honey can help wounds to heal is something that was known to the Ancient Egyptians several thousand years ago. And in the last two world wars poultices with honey were used to assist the healing process in soldiers' wounds. However, the rise of the new antibiotics replaced this household remedy. 'In hospitals today we are faced with germs which are resistant to almost all the current anti-biotics,' Dr. Arne Simon explains. 'As a result, the medical use of honey is becoming attractive again for the treatment of wounds.' Dr. Simon works on the cancer ward of the Bonn University Children's Clinic. As far as the treatment of wounds is concerned, his young patients form part of a high-risk group: the medication used to treat cancer known as cytostatics not only slows down the reproduction of malignant cells, but also impairs the healing process of wounds. 'Normally a skin injury heals in a week, with our children it often takes a month or more,' he says. Moreover, children with leukaemia have a weakened immune system. If a germ enters their bloodstream via a wound, the result may be a fatal case of blood poisoning. For several years now Bonn paediatricians have been pioneering the use in Germany of medihoney in treating wounds. Medihoney bears the CE seal for medical products; its quality is regularly tested. The success is astonishing: 'Dead tissue is rejected faster, and the wounds heals more rapidly,' Kai Sofka, wound specialist at the University Children's Clinic, emphasises. 'What is more, changing dressings is less painful, since the poultices are easier to remove without damaging the newly formed layers of skin.' Some wounds often smell unpleasant - an enormous strain on the patient. Yet honey helps here too by reducing the smell. 'Even wounds which consistently refused to heal for years can, in our experience, be brought under control with medihoney - and this frequently happens within a few weeks,' Kai Sofka says. In the meantime two dozen hospitals in Germany are using honey in their treatment of wounds. Despite all the success there have hitherto been very few reliable clinical studies of its effectiveness. In conjunction with colleagues from D�sseldorf, Homburg and Berlin, the Bonn medical staff now want to remedy this. With the Woundpecker Data Bank, which they have developed themselves, they will be recording and evalu-ating over 100 courses of disease over the next few months. The next step planned is comparative studies with other therapeutic methods such as the very expensive cationic silver dressings. 'These too are an effective anti-bacterial method,' says Dr. Arne Simon. 'However, it is not yet clear whether the silver released from some dressings may lead to side-effects among children.' Effective bacteria killer It has already been proved that medihoney even puts paid to multi-resistant germs such as MRSA. In this respect medihoney is neck and neck in the race to beat the antibiotic mupirocin, currently the local MRSA antibiotic of choice. This is shown by a study recently published by researchers in Australia. In one point medihoney was even superior to its rival: the bacteria did not develop any resistance to the natural product during the course of treatment. It is also known today why honey has an antiseptic effect: when producing honey, bees add an enzyme called glucose-oxidase. This enzyme ensures that small amounts of hydrogen peroxide, an effective antiseptic, are constantly being formed from the sugar in the honey. The advantage over the hydrogen peroxide from the chemist's is that small concentrations are sufficient to kill the germs, as it is constantly being produced. As a rule much larger quantities of hydrogen peroxide would have to be used, as hydrogen peroxide loses its potency over time. However, in large concentrations it not only damages the bacteria, but also the skin cells. Furthermore, medihoney consists of two different types of honey: one which forms a comparatively large amount of hydrogen peroxide, and another known as 'lepto-spermum honey'. Leptospermum is a species of tree which occurs in New Zealand and Australia. Honey from these trees has a particularly strong anti-bacterial effect, even in a 10% dilution. 'It is not yet known exactly why this is,' Dr. Arne Simon says. 'Probably it is a mix of phenol-type substances which come from the plant and make life particularly difficult for the bacteria in the wound.'
четверг, 13 декабря 2007 г.
Fewer Heart Patients Need Antibiotics Before Dental Procedures
Based on a review of new and existing scientific evidence, most dental patients with heart disease do not need antibiotics before dental procedures to prevent infective endocarditis (IE), a rare, but life-threatening heart infection.According to revised guidelines from the American Heart Association (AHA) with input from the American Dental Association (ADA), antibiotics are now only recommended for patients at greatest risk of negative outcomes from IE including those with artificial heart valves or certain congenital heart conditions, heart transplant recipients who develop cardiac valve problems, recipients of an artificial patch to repair a congenital heart defect within the past six months and patients with a history of IE.The AHA's latest guidelines were published in its scientific journal, Circulation, in April. The Guidelines apply to a range of medical and dental procedures. The ADA is publishing those portions of the new guidelines relevant to dentistry on its Web site (http://www.ada.org/goto/endocarditis) today and in the June issue of the Journal of the American Dental Association (JADA).For decades, the AHA recommended that patients with certain heart conditions take antibiotics shortly before dental treatment. This was done with the belief that antibiotics would prevent IE, previously referred to as bacterial endocarditis. IE is an infection of the heart's inner lining or valves, which results when bacteria enter the bloodstream and travel to the heart. Bacteria are normally found in various sites of the body including on the skin and in the mouth.The ADA participated in the development of the new guidelines and has approved those portions relevant to dentistry. The guidelines are also endorsed by the Infectious Diseases Society of America and by the Pediatric Infectious Diseases Society.The new guidelines are based on a growing body of scientific evidence that shows the risks of taking preventive antibiotics outweigh the benefits for most patients. The risks include adverse reactions to antibiotics that range from mild to potentially severe and, in rare cases, death. Inappropriate use of antibiotics can also lead to the development of drug-resistant bacteria.Scientists also found no compelling evidence that taking antibiotics prior to a dental procedure prevents IE in patients who are at risk of developing a heart infection. Their hearts are already often exposed to bacteria from the mouth, which can enter their bloodstream during basic daily activities such as brushing or flossing. The new guidelines are based on a comprehensive review of published studies that suggests IE is more likely to occur as a result of these everyday activities than from a dental procedure.The guidelines say patients who have taken prophylactic antibiotics routinely in the past but no longer need them include people with mitral valve prolapse, rheumatic heart disease, bicuspid valve disease, calcified aortic stenosis, or congenital heart conditions such as ventricular septal defect, atrial septal defect and hypertrophic cardiomyopathy.The new recommendations apply to many dental procedures, including teeth cleaning and extractions.The guidelines emphasize that maintaining optimal oral health and practicing daily oral hygiene are more important in reducing the risk of IE than taking preventive antibiotics before a dental visit.
среда, 12 декабря 2007 г.
Tailor-made Antibiotics, Protein Clue
Scientists at the University of York have made a huge leap forward in the search for 'smarter' antibiotics. A research group in the Department of Biology has made a significant advance in understanding how bacteria use proteins to conduct a type of biological warfare. Bacteria like E. coli frequently try to kill each other when resources are scarce using protein antibiotics called colicins, which are potent toxins. The research led by Professor Colin Kleanthous has discovered a critical element in the mode of action of a class of colicins (so-called DNases) that kill cells by destroying their DNA. Though most proteins have a folded structure, DNase colicins are only partially so. The scientists have found that the unfolded part of DNase colicin structure makes its way into an unsuspecting bacterium and blocks a key process that lowers the cell's defences and allows the toxin to enter. Professor Kleanthous said: "Antibiotic resistance is on the increase throughout the world. Understanding how bacteria have evolved to kill each other with protein toxins might offer ways of constructing new, tailor-made antibiotics that target particular microorganisms." Researchers are now trying to establish what it is about this blocking mechanism (which they've christened 'competitive recruitment') that lowers the cells' defences toward the colicin.
вторник, 11 декабря 2007 г.
Controlling Antibiotics And Antibiotic Resistance In Hospitals
In one of the first national studies on guidelines that control antibiotics and antibiotic resistance in hospitals, researchers from the Indiana University School of Medicine, the Regenstrief Institute, Inc. and the Richard Roudebush Veterans Administration Medical Center report that hospitals that follow national guidelines on controlling antibiotic use have lower rates of antibiotic resistance. In a study published in the October issue of Infection Control and Hospital Epidemiology, the researchers studied four major types of antibiotic resistance at almost 450 hospitals, looking at what each hospital did to control antibiotic use and how this affected the rate of antibiotic resistance. "We saw in this study, as in other work we have done, that antibiotic resistance is increasing rapidly. This increase is seen in all types of hospitals across the country - large and small, teaching and non-teaching, VA and non-VA," said Bradley N. Doebbeling, M.D., M.Sc., who led the study. He directs the IU Center for Health Services and Outcomes Research at the Regenstrief Institute and the IU School of Medicine. He also directs the VA Center for Implementing Evidence-Based Practice. The study looked at measures to prevent development of antibiotic resistance as well as ways to stop its spread. The researchers reported that if hospitals implemented specific measures to control the use of antibiotics they were more likely to have succeeded in controlling antibiotic resistance. Surprisingly, use of information technology didn't seem to have an impact. "We think that's because so few hospitals have the necessary technology available to support decisions related to prescribing antibiotics such as start and stop rules and how to use the best drug," said Dr. Doebbeling. Prescription of antibiotics fall into three categories (1) preventive, often administered before or during surgery; (2) empiric - prescribed before the physician knows the specific nature of the bacteria; and (3) targeted - prescribed after bacterial culture results identify the bacteria actually causing the infection. The study found that if a hospital had implemented measures to control the duration of administration of an empiric antibiotic, the institution had lower antibiotic resistance rates. Having a restricted hospital formulary that limited the antibiotics available in the hospital was associated with a higher prevalence of antibiotic resistance, while simply limiting broad spectrum drugs helped prevent resistance. "We think this may be because wrong decisions are made about which antibiotics are made available. Other studies have shown evidence that restricting formularies to previously effective antibiotics can actually help control antibiotic resistance," said Dr. Doebbeling.
понедельник, 10 декабря 2007 г.
Are Antibiotics Being Used For Too Long?
Taking antibiotics for three days is just as effective for community acquired pneumonia as continuing treatment for the recommended 7-10 days, finds a study in this week's BMJ. Shorter treatment can also help contain growing resistance rates. The study raises questions about the optimal duration of antibiotic therapy for common infections. Community acquired pneumonia is one of the most important indications for antibiotic prescriptions in hospitals. But a lack of evidence to support short course therapy means it has become accepted practice to continue treatment for days after symptoms have improved. Researchers in the Netherlands compared the effectiveness of discontinuing treatment with amoxicillin after three days or eight days in adults admitted to hospital with mild to moderate-severe community acquired pneumonia. 119 patients who substantially improved after the conventional three days' treatment with intravenous amoxicillin were randomly assigned to oral amoxicillin (63 patients) or placebo (56 patients) three times daily for five days. Patients were assessed at days 7, 10 (two days after treatment ended), 14, and 28. In the three day and eight day treatment groups, the clinical success rate at day 10 was 93% for both, and at day 28 was 90% compared with 88%. Both groups had similar resolution of symptoms, x-ray results, and length of hospital stay. These findings show that discontinuing amoxicillin treatment after three days is not inferior to discontinuing it after eight days in adults with mild to moderate-severe community acquired pneumonia who have substantially improved after an initial three days' treatment, say the authors. A shorter duration of treatment can also help to reduce overall antibiotic consumption and resistance rates for respiratory infections, they conclude. This study suggests that current guidelines recommending 7-10 days should be revised, says Dr John Paul from the Royal Sussex County Hospital, in an accompanying commentary. Not only does the study yield strong evidence in favour of short course therapy for a subset of patients with community acquired pneumonia, but also shows how centres can cooperate to tackle longstanding areas of uncertainty in clinical microbiology and infectious diseases, he writes. Many other common clinical situations would repay the efforts of comparable approaches.
воскресенье, 9 декабря 2007 г.
Targeted Antibiotics Lead To Prolonged Improvement In IBS Symptoms
Researchers at Cedars-Sinai Medical Center have found that a nonabsorbable antibiotic - one that stays in the gut - can be an effective long-term treatment for irritable bowel syndrome (IBS), a disease affecting more than 20 percent of Americans.The study, which appears in the October 17 issue of the Annals of Internal Medicine, is the first to demonstrate benefits from antibiotic use even after the course of treatment has ended, supporting previously published research that identified small intestine bacterial overgrowth as a cause of the disease.The randomized, double-blind, placebo-controlled study involved 87 participants, all of whom met specific multinational guidelines for diagnosis of IBS. They received 400 mg of the antibiotic rifaximin three times a day for 10 days or a placebo. Participants completed an extensive symptom questionnaire at the start of the study and then weekly for 10 weeks following treatment. The questionnaire measured the severity of nine symptoms (abdominal pain, diarrhea, constipation, bloating, urgency, incomplete evacuation, mucus, sense of incomplete evacuation, and gas). Patients were also asked to provide a percent global improvement from 0 to 100 percent in their overall IBS symptoms.Researchers found that the rifaximin not only led to significant improvement in global IBS symptoms during the 10 days it was administered, but also that the benefit continued for the 10 weeks of follow up when no antibiotic was given, showing sustained benefit."The fact that the benefit of the targeted antibiotic continued even after it was stopped provides evidence that the antibiotic was acting on a source of the problem: excess bacteria in the gut," said Mark Pimentel, M.D., director of the GI Motility Program at Cedars-Sinai and the study's principal investigator. "This finding offers a new treatment approach - and a new hope - for people with IBS."Irritable Bowel Syndrome is one of the top 10 most frequently diagnosed conditions by U.S. physicians. It is an intestinal disorder that causes abdominal pain, cramping, bloating and diarrhea and/or constipation and is a long-term condition that usually begins in early adult life. Episodes may be mild or severe and may be exacerbated by stress. IBS is more common in women than in men."While this study being released today demonstrates that the non-absorbed antibiotic rifaximin has great promise in the clinical improvement of IBS, more research is needed," said Pimentel. "Next steps include multi-center studies to further assess short- and long-term benefits of this drug. Tests comparing rifaximin to other types of antibiotics that have been used to treat the disease should also be conducted."Because the cause of IBS has been elusive, treatments for the disease have historically focused on reducing its symptoms - diarrhea and constipation - by giving medications that either slow or speed up the digestive process. In The American Journal of Gastroenterology (Dec. 2000), Pimentel linked bloating, the most common symptom of IBS, to bacterial fermentation by giving lactulose breath tests to participants. The test, which monitors the level of hydrogen and methane (the gases emitted by fermented bacteria) on the breath, showed evidence that small intestine bacteria overgrowth may be a causative factor in IBS.Participants in the current Annals study also took the breath tests, which showed similarly increased levels of hydrogen and methane.Rifaximin, an antibiotic that is FDA-approved for travelers' diarrhea in this country, is made by Salix Pharmaceuticals, Inc. Funding for the study was also provided by Salix. The discovery related to the use of rifaximin for IBS was made at Cedars-Sinai by Pimentel. Cedars-Sinai holds patent rights to this discovery and has licensed rights to the invention to Salix.Other authors from Cedars-Sinai include Sandy Park, James Mirocha, and Yuthana Kong. Sunanda V. Kane from the University of Chicago also participated in the study.
суббота, 8 декабря 2007 г.
Antibiotic Resistant Bacteria In Poultry Could Threaten Human Health
A surprising finding by a team of University of Georgia scientists suggests that curbing the use of antibiotics on poultry farms will do little - if anything - to reduce rates of antibiotic resistant bacteria that have the potential to threaten human health. Dr. Margie Lee, professor in the UGA College of Veterinary Medicine, and her colleagues have found that chickens raised on antibiotic-free farms and even those raised under pristine laboratory conditions have high levels of bacteria that are resistant to common antibiotics. Her findings, published in the March issue of the journal Applied and Environmental Microbiology, suggest that poultry come to the farm harboring resistant bacteria, possibly acquired as they were developing in their eggs. "The resistances don't necessarily come from antibiotic use in the birds that we eat," Lee said, "so banning antibiotic use on the farm isn't going to help. You have to put in some work before that." Lee and her team sampled droppings from more than 140,000 birds under four different conditions: 1.) commercial flocks that had been given antibiotics; 2.) commercial flocks that had not been given antibiotics; 3.) flocks raised in a lab that had been given antibiotics; and 4.) flocks raised in a lab that had not been given antibiotics. The researchers examined levels of antibiotic resistance in normal intestinal bacteria that do not cause human illness and - in a companion study published in May in the same journal - also examined levels of drug resistant campylobacter bacteria, a common foodborne cause of diarrhea, cramping and abdominal pain. They found that even birds raised in the pristine laboratory conditions had levels of antibiotic resistance levels comparable to what was seen on farms that used antibiotics. Even when the levels were lower, Lee adds, they were still well above the reasonable comfort zone for antibiotic resistance - roughly five to 10 percent. Seventy-three percent of the bacteria from one flock in the antibiotic-free commercial group were resistant to the drug oxytetracycline, for example, while 90 percent were resistant to the drug in a commercial flock that used antibiotics. Ninety-seven percent were resistant in the experimental flock that was given antibiotics, while forty-seven percent were resistant in the experimental group that was not given antibiotics. Strikingly, they even found bacteria resistant to streptomycin, a common human antibiotic that is rarely used in poultry and was not used on the farms the researchers studied. Bacteria swap genes relatively easily, and Lee explained that the concern is that drug resistance genes from bacteria that infect poultry could be passed on to bacteria that cause human illness. With these resistance genes, human bacterial illness could become harder to treat. These concerns led the European Union to ban the use of antibiotics for growth promotion in chickens in 2006. In 2005, the U.S. Food and Drug Administration banned the use of the drug Baytril - the brand name for enrofloxacin, a fluoroquinolone antibiotic - in poultry, citing concerns that it could lead to resistance in human antibiotics such as Cipro, also a fluoroquinolone. Several advocacy groups are pushing for a more comprehensive animal antibiotic ban in the United States, but Lee said her research plus the evidence from the Baytril ban suggests that approach won't help. "They banned Baytril in 2005, and if you look at Baytril resistance in campylobacter now it's essentially unchanged," Lee said. In previous studies, Lee has tried to recreate experimentally conditions that should lead to the swapping of resistance genes among bacteria. Lee said these events - known as the horizontal transfer of genes - do occur, but they may not be as common as initially thought. What may be driving the antibiotic resistance that Lee has observed in her studies is what's known as vertical transfer - from parent to child - of bacteria carrying resistance genes. In short, the birds may come to the farm harboring antibiotic resistant bacteria. "This issue of antibiotic resistance is more complicated than once thought," Lee said. "These findings suggest that banning antibiotics at the farm level may not be as effective as assumed. We need further studies to identify which management practice would be effective" Lee stresses that for consumers, the advice on poultry is the same that it's always been. Cook meat thoroughly and use proper food handling and preparation techniques - washing your hands regularly and keeping other foods away from raw chicken, for example - to minimize the risk of illness. "All foods have the potential to contain pathogens - all of them," Lee said. "There's no substitute for good food handling and preparation."
пятница, 7 декабря 2007 г.
Antibiotics Over-Prescribed By GPs
GPs are unnecessarily giving patients antibiotics for respiratory tract (RT) infections which would clear up on their own. Doctors tend to over-emphasise symptoms such as white spots in the throat, rather than looking at factors such as old age and co-morbidity, which would affect a patient's recovery, according to an article published in the online open access journal, BMC Family Practice.Huug J. van Duijn and his team at the Julius Center for Health Sciences and Primary Care from the University Medical Center Utrecht, The Netherlands, looked at the practice records of 163 GPs from 85 Dutch practices over a 12 month period, and carried out a survey of the doctors' attitudes to prescribing antibiotics for RT infections. Diagnostic labelling (the tendency to encode RT episodes as infections rather than as symptoms) seemed to be an arbitrary process, often used to justify antibiotic prescribing. GPs may give out antibiotics unnecessarily to defend themselves against unforeseen complications, even if these are unlikely to materialize.Although Dutch GPs prescribe relatively small antibiotic volumes and international colleagues often envy the quality assurance system in Dutch primary care with guidelines and peer review groups, Van Duijn suggests that the results of his study should be used to update quality assurance programs and postgraduate courses, to emphasise the use of evidence-based prognostic criteria (e.g. chronic respiratory co-morbidity and old age) as an indication to prescribe antibiotics instead of single signs of inflammation or diagnostic labels. "Even in the Netherlands there is an over-prescribing of antibiotics; about 50% of the antibiotic prescriptions for acute RT episodes are not in accordance with Dutch national guidelines," says van Duijn. "Considering costs, side-effects and the growing resistance to pathogens, it is important to rationalise antibiotic prescribing as much as possible."
четверг, 6 декабря 2007 г.
Alternative To Antibiotics May Be More Effective And Less Harmful
Photodynamic therapy (PDT) may be an effective way to treat the bacteria associated with periodontal diseases, and could provide a better option than antibiotics or other mechanical methods for treating periodontal diseases, according to a new study published in the March issue of theJournal of Periodontology. Researchers at São Paulo State University found that using PDT was an effective method to minimize destruction of periodontal tissue which can accompany treatment for periodontal diseases. In a rat population, PDT did minimal damage to periodontal tissues, in comparison to other techniques including scaling and root planing and antibiotic therapy. "We found that PDT is significantly less invasive than other treatments for periodontal diseases," said study author Dr. Valdir Gouveia Garcia, from the Department of Periodontology at São Paulo State University. "It can provide improved dentin hypersensitivity, reduced inflammation of the tissues surrounding the teeth, and allows tissues to repair faster." PDT may be an alternative to antibiotic treatment, which is becoming increasingly important as antibiotic resistance increases. PDT involves two stages; first, a light-sensitive drug is applied to the area. Second, a light or laser is shone on that area. When the light is combined with the drug, phototoxic reactions induce the destruction of bacterial cells. PDT was first approved by the Food and Drug Administration in 1999 to treat pre-cancerous skin lesions of the face or scalp. "This is an exciting finding," said Preston D. Miller, Jr., DDS and President of the American Academy of Periodontology. "PDT may be an effective therapy for the treatment of periodontal diseases. While patients have many options for treating their periodontal diseases, PDT could prove to be a preferable alternative to antibiotic therapy. Unfortunately, long term antibiotic therapy not only decreases the drug's effectiveness, but also may lead to the development of drug resistant organisms. Our Academy supports future research to further define the application of PDT as a means to treat periodontal disease."
среда, 5 декабря 2007 г.
Research May Lead To New Classes Of Antibiotics
Scientists have what could be some very bad news for disease-causing bacteria. All three major classes of antibiotics that kill infectious bacteria do so in part by ramping up the production of harmful free radicals, researchers report in Cell a publication of Cell Press. Because those different types of antibiotics each initially hit different targets, it had been believed they worked by independent means. The findings could point the way to new classes of antibiotics and to a common method by which existing antibiotics could be made to stamp out bacteria even better, according to the Boston University researchers. Such advances are particularly critical at a time when, according to the Centers for Disease Control and Prevention, nearly all significant bacterial infections in the world are becoming resistant to the most commonly prescribed antibiotic treatments. "Hydroxyl radicals damage DNA, which turns on the S.O.S. repair response," said James Collins. "Therefore, our findings suggest that if you could shut off the bacteria's repair response, you might make all bactericidal antibiotics more effective and effective at lower doses. You could in essence create a super-Cipro, super-mycins, and so on." Current antimicrobial therapies fall into two general categories: (1) bactericidal drugs, which kill bacteria with almost complete efficiency, and (2) bacteriostatic drugs, which inhibit their growth, allowing the immune system to clear the infection, Collins's group explained. The targets of bactericidal antibiotics are well studied and predominantly fall into three classes: (1) those that hit DNA, (2) those that hit proteins, and (3) those that hit the bacterial cell wall. In contrast, most bacteriostatic drugs work by blocking the function of ribosomes, which are the sites of protein synthesis. While antibiotics' ability to kill bacteria had been attributed solely to those class-specific drug-target interactions, "our understanding of many of the bacterial responses that occur as a consequence of the primary drug-target interaction remains incomplete," the researchers said. Collins and his colleagues recently uncovered some evidence that at least some antibiotics might have some other deadly tricks. They showed that one type of antibiotics, including quinolones, which block DNA's replication and transcription into messenger RNA, also causes a breakdown that leads to the production of free radicals. Moreover, they found that those highly reactive chemicals help finish the bacteria off. In the new study, the researchers wanted to know whether other antibiotics also drive the toxic brew. Indeed, they show, drugs that kill bacteria all do cause a rise in free radicals, and all in the same manner. This is not so for drugs that only stunt bacteria's growth, they report. "The ever-increasing prevalence of antibiotic-resistant strains has made it critical that we develop novel, more effective means of killing bacteria," the researchers concluded. "Our results indicate that targeting bacterial systems that remediate hydroxyl radical damage, including proteins involved in triggering the DNA damage response… is a viable means of potentiating all three major classes of bactericidal drugs. Moreover, pathway analyses and systems biology approaches may uncover druggable targets for stimulating hydroxyl radical formation, which could result in new classes of bactericidal antibiotics."
вторник, 4 декабря 2007 г.
APhA Calls For Appropriate Use Of Antibiotics - Pharmacists And Other Healthcare Professionals Can Educate The Public
The American Pharmacists Association (APhA), the national professional society of pharmacists, encourages patients to talk to their pharmacist and healthcare professional about proper antibiotic use, prevention of antibiotic resistance, and appropriate infection control. Tens of thousands of deaths and an estimated 1 million hospital infections are blamed on antibiotic resistant bacteria each year. According to an article in the October 17, 2007 issue of the Journal of the American Medical Association (JAMA), inappropriate and overuse of antibiotics is a major contributing factor to the development of antibiotic resistant bacteria. "Pharmacists, as the medication use specialists, have the knowledge and skills to assist with the selection and appropriate use of antibiotics," according to John Gans, APhA Executive Vice President. "The battle against drug-resistant infections requires a commitment by healthcare providers and patients to protect the public's health." Drug-resistant bacteria include methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci, and resistant strains of Streptococcus pneumonia. Infections caused by MRSA appear to be more prevalent than previously believed and are being found more often outside of health care settings, according to the JAMA study. MRSA has become the most frequent cause of skin and soft tissue infections among patients presenting to emergency departments in the United States, and can also cause severe, sometimes fatal invasive disease. APhA, in accordance with the Centers for Disease Control and Prevention, recommends the following antibiotic use and infection prevention tips: Appropriate Antibiotic Use- Know how to take your medication. Complete prescribed courses of treatment (don't skip doses) even if you are feeling better. - Do not demand antibiotics when a health care provider has determined they are not needed. - Do not take antibiotics prescribed for someone else. The antibiotic may not be appropriate for your illness. Taking the wrong medicine may delay correct treatment and allow bacteria to multiply. - Do not save any antibiotics for the next time you get sick. Appropriately discard any leftover medication once you have completed your prescribed course of treatment. - Do not take an antibiotic for a viral infection like a cold, a cough or the flu. - Ask your pharmacist if you have questions about your medication therapy. Prevention of Infection- Be up-to-date on your immunizations. - Watch for signs of infection (unexpected pain, chills, or fever or drainage or increased inflammation from wounds), especially if recently discharged from hospitals. - See a physician promptly if you have a suspicious skin sore or boil. - Wash hands thoroughly and often with soap and water. - Ask health care workers to wash their hands before examinations. - Keep cuts and abrasions clean and covered with a bandage until healed. - Avoid contact with other people's wounds or material contaminated by wounds. - Do not share items such as razors, soap, ointments and balms, towels or wash cloths, clothing or uniforms. - If participating in contact sports, cover cuts, scrapes and other wounds with a bandage. - Shower with soap immediately after each practice or game. Wipe down all nonwashable equipment (mats, head protectors, gymnastics equipment, etc.) with alcohol or antibiotic solution after each person uses it. - If caring for someone with an infection at home, wash hands with soap after each physical contact and before going outside. Only use towels for drying hands once. Change and launder linens frequently, right away if they are soiled.
понедельник, 3 декабря 2007 г.
Too Many Antibiotics Prescribed For Sinus Infections
US scientists researching treatments for sinus infections suggest that antibiotics are overprescribed to treat the condition. And they are concerned this could be increasing the drug resistance and virulence of infectious bacteria.The study is published in the March issue of Archives of Otolaryngology-Head & Neck Surgery.According to the study, by Hadley J. Sharp and colleagues at the University of Nebraska Medical Center, Omaha, US, antibiotics were prescribed for 82 per cent of acute sinus infections and nearly 70 per cent of chronic sinus infections.This is surprising because most sinus infections are caused by viruses, and antibiotics only kill bacteria. The scientists used national data from 1999 and 2002 to find out which drugs were being prescribed for sinus infections by general practitioners, outpatient and emergency departments. The data was representative of the US population and came from two national surveys collected by the National Center for Health Statistics.Rhinosinusitis, commonly known as sinus infection or sinusitis, is an inflammation of the sinus cavities that connect with the nasal passage. According to the study, it is a common and expensive medical condition in the US.Acute sinusitis occurs for up to 4 weeks and is thought to be caused mostly by infectious agents. Chronic sinusitis is thought to be affected mostly by allergies, hormone changes and facial anatomy and symptoms persist for 12 or more weeks.In 2002, of all the antibiotic prescriptions that year in the US, 21 per cent were for adults with sinus infections and 9 per cent was for children.According to the survey data, over 14 million visits are paid to health care facilities in the US every year are for chronic sinusitis, while over 3 million are for acute sinusitis. As a proportion of all ambulatory care in the US per year, chronic sinusitis represents 1.39 per cent of visits and acute sinusitis 0.30 per cent.In 69.95 percent of visits for chronic sinusitis at least one antibiotic was prescribed. For acute sinusitis this figure was 82.74 per cent.Sharp and colleagues assessed that "The most frequently recommended medications for treatment of both acute and chronic rhinosinusitis are antibiotic agents, followed by antihistamines; nasal decongestants; corticosteroids; and antitussive, expectorant and mucolytic agents, respectively".The most commonly used antibiotics for both chronic and acute bacterial infections were penicillins (mainly amoxicillin and amoxicillin-clavulanate potassium, brand name Augmentin). These were prescribed appropriately, they said, with 30.35 per cent of chronic and 27.18 per cent of acute infection visits mentioning penicillin prescriptions.However, the researchers questioned the use of the stronger antibiotics such as erythromycins, lincosamides, and macrolides, amongst others. These were mentioned in 24.32 per cent of acute sinusitis visits, which, in order, makes them more frequently prescribed than cephalosporins, sulfonamides and trimethprim, and tetracyclines.The authors assessed the relative proportions of the causes of sinusitis from other studies. Comparing these proportions with the relative proportions of what is actually being prescribed to treat sinusitis they found major discrepancies.They concluded that "Prescription antibiotic drugs are being used far more than bacterial causes studies would indicate." Sharp and colleagues also assessed that "Nasal and inhaled corticosteroids are prescribed more frequently to treat acute rhinosinusitis than published studies imply is necessary". However, they estimated that where antihistamines were prescribed, this was roughly in proportion with estimated prevalence of allergic sinusitis.In trying to fathom why the use of antibiotics is so high, the authors suggest that some doctors could be trying to treat secondary infections. On the other hand, it could be because doctors think antibiotics are working because patients get better while taking them, whereas they could be getting better anyway.They express concern about the problems that overuse of antibiotics bring, including drug resistance and increased virulence of bacteria.They conclude, "When two-thirds of patients with sinus symptoms expect or receive an antibiotic and as many as one-fifth of antibiotic prescriptions for adults are written for a drug to treat rhinosinusitis, these disorders hold special pertinence on the topic."
воскресенье, 2 декабря 2007 г.
Hearing Loss Due To Antibiotics May Be Prevented By Genetically Screening Patients Beforehand
Some patients have a genetic mutation which means they are more at risk of hearing loss after taking antibiotics called aminoglycosides. Experts, writing in the British Medical Journal (BMJ) believe that screening patients for this genetic mutation may prevent this. The writers, Maria Bitner-Glindzicz and Shamima Rahman, the Institute of Child health, London, England, explain that aminoglycosides are valuable antibiotics for such serious infections as complicated urinary tract infections, tuberculosis and septicemia. They are known to potentially cause damage to the ear (otoxicity). However, what isn't well known is that there are people who have an inherited predisposition that makes them extremely sensitive to the effects - they can end up with severe and permanent hearing loss. Approximately 5% of deafness in children in the UK is caused by this mutation, known as m.1555A-G. About 1 in 40,000 people in the UK have this mutation. Studies in other countries have indicated much higher incidences, in New Zealand it is thought to occur in 1 in 206 cases of newborns, and 1 in 1,161 in the USA (also newborns). Families carrying this mutation, even if they never take aminoglycosides, may develop some degree of deafness later in life. A study carried out in Spain found that 27% of families which included two deaf people were positive for this mutation. It was also found that everybody who had this mutation in Spain and took aminoglycosides suffered from hearing loss. A person who had taken aminoglycosides had a 96.5% of becoming deaf by the age of 30 if he/she had been exposed to aminoglycosides, while 38.9% of those who had never taken it became deaf. The authors write that aminoglycosides are a major environmental modifier of the m.1555A-G mutation. The writers ask whether it is cost effective to screen for this mutation before deciding whether to prescribe aminoglycosides. A test in the UK costs approximated £35 ($70). This cost would probably go down considerably if they were carried out in much larger numbers. It costs the NHS £61,000 ($122,000) for every child who becomes deaf (over his/her lifetime), plus about £18,000 ($36,000) in educational costs. US estimates have placed the lifetime cost to society for a child who loses his/her hearing before acquiring language at one million dollars. It is possible to prevent deafness brought on by aminoglycosides in individuals who have this genetic mutation, explain the authors. Doctors who have patients who are deaf are well aware of this mutation. Many doctors, however, do not know about this susceptibility, and many others do not know that mutation testing is available. The authors propose that the true prevalence of this mutation be ascertained for the UK, so that the cost-effectiveness of screening everyone who is prescribed aminoglycosides can be determined. Until this is done, people who are likely to be receiving multiple courses of aminoglycosides should be screened, such as leukemia patients and infants admitted to special care baby units. They conclude that test results should be produced rapidly, and until they appear the patient should be given some other type of antibiotic.
суббота, 1 декабря 2007 г.
Antibiotic Resistance In Humans Researched Using Pig Model
Pigs could be the key to understanding how antibiotic resistant bacteria persist in Intensive Care Units in hospitals. NSW Department of Primary Industries (NSW DPI) Immunology & Molecular Diagnostic Research Unit Team Leader, Dr James Chin, says it is commonly believed that each time an antibiotic is used only pathogens or disease-causing bacteria will be killed. "Antibiotic use in hospitals is often perceived to be solely directed against only bad bacteria. "In reality, antibiotics also act against entire microbial communities, including the good bacteria which can protect patients from pathogenic bacteria. "Antibiotics do not just eliminate bad bacteria", Dr Chin said. "They also maintain a pool of antibiotic resistance genes within the microbial community of patients treated with antibiotics." Using pigs as a model, Dr Chin and Dr Toni Chapman at NSW DPI's Elizabeth Macarthur Agricultural Institute have examined how E.coli bacteria -- a common cause of diarrhoea in pigs and humans -- respond to treatment by antibiotics. Dr Chin told the 2007 Australian Society for Microbiology's annual conference in Adelaide in July that: "The current theory of antibiotic resistance is that the 'fittest' bacteria, that is, those carrying genes for resistance, are the most likely to survive. "Because antibiotic treatment will never kill all bacteria, bad or good, there will always be a pool of antibiotic resistance bacteria that can potentially transfer resistance to incoming pathogens. "It is important to identify the antimicrobial resistant gene pool in entire microbial communities before antibiotic treatment. Dr Chin said this has been tested with E. coli in pigs. "Our research shows clearly that use of one antibiotic to treat E. coli not only increases resistance against that antibiotic but also increases the carriage of resistance genes against other classes of antibiotics. "This creates a real problem because subsequent therapy with a second antibiotic may be ineffective because resistance against the second antibiotic had already been increased by the first antibiotic." In the United States an estimated 10 percent of patients get sick because of infections acquired whilst being treated in hospital. More careful use of antibiotics is regarded as vital. Dr Chin said the use of antibiotics for disease prevention is critical in patients admitted to intensive care. However there is currently a major bottleneck when it comes to deciding which antibiotics to use. "Current protocols require pathogens to be cultured, leading to delays of some days before the bacteria to be targeted can be accurately identified. Dr Chin said for this reason it is important to develop a molecular detection method that can identify antibiotic resistance signatures of entire microbial communities. "Our hope is that this kind of information will equip clinicians to better manage prescribing of antibiotics." This latest research is being planned in collaboration with clinical microbiologists and intensive care specialists at Westmead Hospital.
пятница, 30 ноября 2007 г.
Intensive care patients, given a cocktail of antibiotics, have better survival rates
Giving a cocktail of antibiotics to intensive care patients may cut the number who die, say researchers. Dutch researchers writing the Lancet journal suggest that wiping out gut microbes could prevent life-threatening infections from taking hold. Their study found that hospital deaths were cut by a quarter after antibiotic treatments were given. However, there are fears that the technique could foster new strains of dangerous 'superbugs'. The practice of 'selective decontamination' - as the drug treatment is called - has been around for decades, and still practiced in many hospitals around the world. However, there is still fierce debate over the benefits of giving the cocktail of drugs to intensive care patients. Weakened People in these units are unusually vulnerable to infection - not only are they physically weakened by their illness or injury, but they often have 'wounds' - including intravenous lines for the delivery of fluids or drugs. The human gut contains a wide variety of bacteria which could, in theory, cause serious infection if they got into these wounds. The researchers, from the universities of Amsterdam and Utrecht wanted to test the theory that killing the majority of potentially harmful bacteria as soon as the patient arrived in the intensive care unit could reduce the risk of them dying in hospital, or at least reduce the amount of time spent there. On a random basis, they gave 934 patients either normal treatment or a cocktail of three antibiotics and one anti-fungal drug over a period of four days. In the 'decontamination' group, 69 patients died, compared with 107 in the normally-treated group - 15% as opposed to 23%. Hospital stays were shorter for the 'decontamination' group, as were costs associated with drug treatment - perhaps reflecting that these patients did not need to be treated for so many infections. Antibiotic resistance However, there are fears that widespread use of antibiotics might be counterproductive - increasing the risk of drug-resistant strains emerging and causing even greater problems for individual patients, and entire intensive care units. Dr Jonathan Cooke, a member of a Department of Health advisory committee on anti-microbial resistance, said he would be unsure about the merits of the practice becoming widespread in the UK. In recent years, there has been a drive to cut the amount of antibiotics used in hospitals to restrict the emergence of resistant bacteria. 'This is something that has gone in and out of vogue over the years - and I am not sure about it. 'It might yield a benefit to start with - but ultimately make things worse.' Surprisingly, however, patients in the treated group were less likely to become 'colonised' with resistant strains of bacteria such as enterococci and Pseudonomas aeruginosa than those given normal treatment. The authors of the report say that unless the hospital has particular problems with 'superbugs', then the approach could cut death rates in intensive care units.
четверг, 29 ноября 2007 г.
Antibiotics not necessary for children with simple skin abscess
DALLAS (USA) - Physicians may not need to prescribe antibiotics when treating a common skin infection in children, according to researchers at UT Southwestern Medical Center at Dallas. The findings, which appear in the February issue of The Pediatric Infectious Disease Journal, show draining a skin or soft-tissue abscess - a pus-filled boil - and packing the wound with gauze is adequate therapy for simple skin abscesses. Patients still need to seek medical attention for these boils even though they may not need antibiotics. This traditional treatment is even effective when the antibiotic-resistant, methicillin-resistant Staphylococcus aureus (MRSA) causes the abscess. Children can get these boils from a scratch or prick, even when there are no known signs of a preceding trauma.Antibiotic-resistant bacteria are often thought to be more virulent than their ancestors, said Dr. R. Doug Hardy, assistant professor of internal medicine and pediatrics and the study's senior author. Many physicians now have questions regarding how aggressively to treat these antibiotic-resistant bacteria. 'We were surprised. What we found is that if a physician adequately drains the abscess, it will most likely get better with or without effective antibiotics,' Dr. Hardy said. At the beginning of the study, researchers were simply looking for alternative drugs and treatments for the methicillin-resistant Staphylococcus aureus. Abscesses caused by these bacteria have become extremely common in children.'I think it's good news for physicians. It addresses the dilemma of how to treat these kids,' said Dr. Michael C. Lee, assistant professor of pediatrics and co-lead author of the study. 'We needed a plan, and we needed to know how to deal with it better on a day-to-day basis.'The study is among the first to look at managing an infection caused by antibiotic-resistant bacteria, researchers said. Previous research has focused mainly on identifying antibiotic-resistant bacteria and determining frequency and risk of infections.The prospective study, one of the largest to date on this subject, included 69 children. Patients' average age was 5? years. All children had their abscesses drained through incision, manually or spontaneously. Nearly all were initially treated with ineffective antibiotics before physicians knew whether patients were infected with the resistant bacteria. In 21 children, the prescribed antibiotics were changed on their first follow-up visit to drugs that could kill the resistant bacteria, while in 37 children antibiotics were not adjusted. On further follow-up, researchers found no statistically significant differences with regard to fever or wound tenderness, discharge or size in patients whose antibiotic therapy was changed compared to those whose therapy was not changed to an effective antibiotic. Four patients were hospitalized on the initial follow-up visit because the abscess had either increased or had not improved as physicians expected. One third of the patients with an abscess and cellulitis more than 5 centimeters in diameter were hospitalized. Ineffective antibiotic use from the initial visit did not predict whether a child would need to be hospitalized, according to the study. It is not known if these findings apply to infants.
среда, 28 ноября 2007 г.
Antibiotics may not be enough to stop recurrent gastric lymphoma caused by Helicobacter pylori
Research led by Dr. Anne Mueller at Stanford University School of Medicine demonstrates that successful eradication of Helicobacter may not prevent future aggressive gastric lymphoma since resting B cells are left behind. The paper by Mueller et al., "The role of antigenic drive and tumor-infiltrating accessory cells in the pathogenesis of Helicobacter-induced MALT lymphoma," appears in the September issue of The American Journal of Pathology. Helicobacter pylori, a spiral bacterium of the stomach, infects more than half of the world's population. It is now widely accepted that, aside from gastritis and ulcers, H. pylori is also a causative agent of gastric lymphoma, specifically gastric B cell lymphoma of mucosa-associated lymphoid tissue (MALT). While antibiotic treatment eradicates the bacteria and promotes tumor regression, the effects of re-infection on disease are more severe. To address the effects of re-infection and the role of immune cells in disease progression, Dr. Mueller's group used a mouse model of Helicobacter-induced MALT lymphoma that employs H. felis to mimic human disease in the mouse. Mice were infected with H. felis and maintained for 18 months before being assigned to one of three treatment groups: 1) no treatment (primarily infected), 2) antibiotic therapy to eradicate bacteria, or 3) antibiotic therapy followed by re-infection. As expected, low-grade MALT lymphoma occurred in 35% of all infected animals. However, frank MALT lymphoma was more prevalent in re-infected animals (44%) than in primarily infected animals (25%). Transcription profiling identified B cell markers in mice that had been infected at any point in time, even after successful antibiotic treatment, suggesting that resting B cells remain in the gastric mucosa. Lymphoid aggregates of re-infected animals also contained more proliferating cells than those of primarily infected or antibiotic-treated animals (46% vs. 23.2% or 4.8%, respectively). Closer inspection of the lymphoid aggregates revealed that the tumors were indeed derived from B cells and the main antigen-presenting cells were follicular dendritic cells. Finally, follicular dendritic cell numbers were highest in the tumors of re-infected animals followed by primarily infected and then antibiotic-treated animals, thus correlating with severity of gastric lymphoma. Because it is the follicular dendritic cells that present antigen to T cells that in turn activate B cell proliferation, follicular dendritic cells appear to be better indicators of tumor behavior than B cells. Thus, follicular dendritic cells represent an untapped target in the fight against recurrent gastric lymphoma. The significance of the described work is that gastric lymphoma progresses more rapidly upon secondary infection. Because resting B cells are left behind following antibiotic treatment, re-infection by H. pylori promotes the existing B cells to progress quickly into tumors. Therefore, it is important that treated patients be carefully monitored for H. pylori re-infection. Mueller A, O'Rourke J, Chu P, Chu A, Dixon MF, Bouley DM, Lee A, Falkow S: The role of antigenic drive and tumor-infiltrating accessory cells in the pathogenesis of Helicobacter-induced MALT lymphoma. Am J Pathol 2005, 167:797-812Research was supported by the National Institutes of Health (US), the Emmy-Noether-Program of the Deutsche Forschungsgemeinschaft (Germany), and J National Health and Medical Research Council (Australia). The American Journal of Pathology, the official journal of the American Society for Investigative Pathology (ASIP), seeks to publish high-quality original papers on the cellular and molecular mechanisms of disease. The editors accept manuscripts which report important findings on disease pathogenesis or basic biological mechanisms that relate to disease, without preference for a specific method of analysis. High priority is given to studies on human disease and relevant experimental models using cellular, molecular, biological, animal, chemical and immunological approaches in conjunction with morphology.
вторник, 27 ноября 2007 г.
Antibiotics and baby asthma
Babies given antibiotics are more likely to develop asthma and other allergies, research suggests. Scientist at Henry Ford Hospital in Detroit say doctors should be more cautious about prescribing the drugs to babies under six months. They believe the drugs may interfere with the development of the gut and therefore the immune system. It is known that antibiotics can kill off beneficial bacteria which live in the gut. More than a million UK children have been diagnosed with asthma, and allergy rates in general are rising. Researcher Christine Cole Johnson said: 'I'm not suggesting that children shouldn't receive antibiotics, but I believe we need to be more prudent in prescribing them for children at such an early age.' Dr Johnson's team studied 448 children, whose development was tracked for the first seven years of their life. By the age of seven, children given at least one antibiotic during their first six months were 2.5 times more likely to have developed asthma than those who were not given the drugs at such a young age. Overall, they were 1.5 times more likely to have developed some form of allergy. Children whose mothers had a history of allergies were particularly at risk. Early use of antibiotics in this group doubled their risk of developing an allergy. Breastfeeding Babies who were breastfed for more than four months, and who received antibiotics in their first six months were three times more likely to develop allergies - although they were no more likely to develop asthma. Exposure to pets, however, seemed to have a protective effect. Those given antibiotics who lived in a family with fewer than two pets had 1.7 times the risk of allergies and three times the risk of asthma. However, when a family had two or more pets, the risk was normal. The biggest risk of all - an 11-fold increase - was found among children who were prescribed a broad-spectrum antibiotic, such as penicillin, were breastfed for four months, and did not have any family pets. The researchers also found evidence that the more courses of antibiotics a child received during their first six months, the higher was their risk of developing an allergy. A spokesman for the National Asthma Campaign said research into the area had proved inconclusive. 'Whilst this is an interesting study, further research is needed to understand the complexities of the relationship between these factors.' Details of the research were presented at the European Respiratory Society's annual conference in Vienna.
понедельник, 26 ноября 2007 г.
Natural Antibiotics Yield Secrets To Atom-Level Imaging Technique
Frog skin and human lungs hold secrets to developing new antibiotics, and a technique called solid-state NMR spectroscopy is a key to unlocking those secrets. That's the view of University of Michigan researcher Ayyalusamy Ramamoorthy, who will discussed his group's progress toward that goal at the annual meeting of the Biophysical Society in Baltimore, Md. Ramamoorthy's research group is using solid-state NMR to explore the germ-killing properties of natural antibiotics called antimicrobial peptides (AMPs), which are produced by virtually all animals, from insects to frogs to humans. AMPs are the immune system's early line of defense, battling microbes at the first places they try to penetrate: skin, mucous membranes and other surfaces. They're copiously produced in injured or infected frog skin, for instance, and the linings of the human respiratory and gastrointestinal tracts also crank out the short proteins in response to invading pathogens. In addition to fighting bacteria, AMPs attack viruses, fungi and even cancer cells, so drugs designed to mimic them could have widespread medical applications, said Ramamoorthy, who is an associate professor of chemistry and an associate research scientist in the Biophysics Research Division. While researchers have identified hundreds of AMPs in recent years, they're still puzzling over exactly how the peptides wipe out bacteria and other microbes. Unlike conventional antibiotics, which typically inhibit specific bacterial proteins, AMPs get downright physical with invaders, punching holes into their membranes. But they're selectively pugnacious, targeting microbes but leaving healthy host cells alone. "They're like smart bombs," Ramamoorthy said. "We'd like to exploit their properties to design super-smart bombs, but before we can do that, we need to understand how these AMP smart bombs interact with membranes to destroy bacteria. We need to know how they're shaped before, during and after the process of attaching to bacteria and how they attach." Solid-state NMR spectroscopy is an ideal tool for answering such questions because it provides atom-level details of the molecule's structure in the complex and challenging cell membrane environment, Ramamoorthy said. "Just as an MRI produces a detailed image of our internal organs, solid-state NMR spectroscopy is used to construct a detailed image of a peptide or protein and to reveal how it sits in the cell membrane," providing clues for modifications that might make synthetic AMPs even more effective in overcoming ever-increasing bacterial resistance. For instance, rearranging parts of the molecule might make it fit into the membrane better, resulting in greater effectiveness with smaller amounts of AMP. "Our overall mission is to use the kind of basic physical data we obtain from solid-state NMR spectroscopy to help interpret biological functions," Ramamoorthy said. The work is highly interdisciplinary, involving not only Ramamoorthy's lab and several other groups in the Chemistry Department, but also researchers from the College of Engineering, the School of Dentistry, the Medical School and the Biophysics Research Division, as well as collaborators in Canada, Japan, India and the U.S. pharmaceutical companies Genaera Corporation and Eli Lilly and Company. Ramamoorthy was awarded support from the National Institutes of Health and the National Science Foundation, through an NSF Faculty Early Career Development Award. A leader in this area of research, he has organized two major international symposia on the field at the University of Michigan, edited a special issue in the journal BBA-Biomembranes, published a number of papers in leading journals, and brought out a book on NMR Spectroscopy of Biological Solids. Ramamoorthy says that this area of research will grow considerably at U-M from implementing plans to set up a high magnetic field solid-state NMR spectrometer facility and an NIH-funded program.
воскресенье, 25 ноября 2007 г.
Prescriptions for antibiotics to prevent anthrax uncommon after the 2001 anthrax attacks
Prescriptions for antibiotics that could be taken in advance to prevent against anthrax were uncommon among concerned patients after September 11, 2001 and the 2001 U.S. anthrax attacks, according to an article in the October 11 issue of The Archives of Internal Medicine, one of the JAMA/Archives journals.According to the article, nationwide, more than 10,000 affected workers and others were given 3.75 million prophylactic antibiotic pills through official dispensing campaigns between October 2001 and January 2002. However, media reports suggest that even more prescriptions were given out by individual physicians. Nathaniel Hupert, M.D., M.P.H., of the Weill Medical College of Cornell University, New York, N.Y., and colleagues reviewed the electronic medical records of outpatient telephone contacts and clinic visits at a large, primary care practice in New York City from September 11 to December 31, 2001 to identify factors associated with prescribing antibiotics to prevent anthrax. There were 30,456 total patient visits (via phone or in person) between September 11 and December 21, 2001. Of these visits, 244 involved patient-initiated discussion about bioterrorism: 92 (0.6 percent) of 14,917 telephone contacts and 152 (1.0 percent) of 15,539 office visits. Average patient volume was higher from October to December in 2001 (221.2 patients per day) compared with the same time period in 2000 (199.1 patients per day). Fifty patients (21 percent of the 244 who discussed bioterrorism with their physician) requested antibiotics or vaccines, and 52 patients (22 percent) received antibiotics: 39 received ciprofloxacin; 12 doxycycline; and 1 received both drugs. "Despite widespread popular concern about bioterrorism and speculation about increased patient requests and physician prescribing of antibiotics for anthrax prophylaxis, only one in five patients who initiated discussion about anthrax or smallpox with physicians at this internal medicine practice in the wake of the 2001 terrorist attacks either requested antibiotics or received them," write the researchers. "While we cannot comment on the New York City population as a whole, our results do not suggest widespread antibiotic abuse in the aftermath of the 2001 terrorist attacks, as measured by patient requests and physician prescribing in this academic outpatient practice," the authors state. "Prescription of antibiotics appropriate for anthrax prophylaxis (i.e., ciprofloxacin, doxycycline, or amoxicillin) was most highly associated with patient requests, followed by report of potential exposure and abnormal findings on physical examination."
суббота, 24 ноября 2007 г.
Hearing Loss Due To Antibiotics May Be Prevented By Genetically Screening Patients Beforehand
Some patients have a genetic mutation which means they are more at risk of hearing loss after taking antibiotics called aminoglycosides. Experts, writing in the British Medical Journal (BMJ) believe that screening patients for this genetic mutation may prevent this. The writers, Maria Bitner-Glindzicz and Shamima Rahman, the Institute of Child health, London, England, explain that aminoglycosides are valuable antibiotics for such serious infections as complicated urinary tract infections, tuberculosis and septicemia. They are known to potentially cause damage to the ear (otoxicity). However, what isn't well known is that there are people who have an inherited predisposition that makes them extremely sensitive to the effects - they can end up with severe and permanent hearing loss. Approximately 5% of deafness in children in the UK is caused by this mutation, known as m.1555A-G. About 1 in 40,000 people in the UK have this mutation. Studies in other countries have indicated much higher incidences, in New Zealand it is thought to occur in 1 in 206 cases of newborns, and 1 in 1,161 in the USA (also newborns). Families carrying this mutation, even if they never take aminoglycosides, may develop some degree of deafness later in life. A study carried out in Spain found that 27% of families which included two deaf people were positive for this mutation. It was also found that everybody who had this mutation in Spain and took aminoglycosides suffered from hearing loss. A person who had taken aminoglycosides had a 96.5% of becoming deaf by the age of 30 if he/she had been exposed to aminoglycosides, while 38.9% of those who had never taken it became deaf. The authors write that aminoglycosides are a major environmental modifier of the m.1555A-G mutation. The writers ask whether it is cost effective to screen for this mutation before deciding whether to prescribe aminoglycosides. A test in the UK costs approximated £35 ($70). This cost would probably go down considerably if they were carried out in much larger numbers. It costs the NHS £61,000 ($122,000) for every child who becomes deaf (over his/her lifetime), plus about £18,000 ($36,000) in educational costs. US estimates have placed the lifetime cost to society for a child who loses his/her hearing before acquiring language at one million dollars. It is possible to prevent deafness brought on by aminoglycosides in individuals who have this genetic mutation, explain the authors. Doctors who have patients who are deaf are well aware of this mutation. Many doctors, however, do not know about this susceptibility, and many others do not know that mutation testing is available. The authors propose that the true prevalence of this mutation be ascertained for the UK, so that the cost-effectiveness of screening everyone who is prescribed aminoglycosides can be determined. Until this is done, people who are likely to be receiving multiple courses of aminoglycosides should be screened, such as leukemia patients and infants admitted to special care baby units. They conclude that test results should be produced rapidly, and until they appear the patient should be given some other type of antibiotic.
пятница, 23 ноября 2007 г.
Oral Antibiotics Effective To Treat Severe Urinary Tract Infections
Although doctors routinely use IV antibiotics to cure patients with severe urinary tract infections (UTI), a new review from suggests that oral antibiotics work just as well from treating acute symptoms to preventing long-term complications of UTI.In light of this evidence, more doctors might consider using oral antibiotics to treat patients with severe UTI, according to German reviewer Dr. Annette Pohl at University Clinic Freiburg.This could potentially lead to far fewer hospitalizations, which, besides avoiding disruption for patients and families, could also considerably reduce hospital and related medical costs."UTIs cause a significant amount of financial burden on the medical system and families," said Hiep Nguyen, M.D., director of robotic surgery and research at the Urological Research Center, Children's Hospital Boston. "It costs us a couple of billion dollars a year to treat children with UTIs and that doesn't account for the money parents lose being out of work when their child is hospitalized."Pohl cautions that treatment with oral antibiotics requires careful supervision to guarantee compliance and to make sure patients are tolerating oral drugs.The review appears in the latest issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.The researchers pooled data from 15 studies of 1,743 patients with severe, symptomatic UTI who received either oral or IV antibiotic treatment. Nine studies involved children, with six studies focusing on children less than one year old. Of the remaining six studies, two comprised women only, including one study of pregnant women.While UTIs are common infections, affecting an estimated 150 million children and adults worldwide every year, they can spread to the kidneys, causing potentially life-threatening complications. A severe upper UTI, known as pyelonephritis, can trigger high blood pressure and cause kidney scarring, which can lead to kidney failure.Current standards for treatment differ depending on the severity of the infection. The treatment for uncomplicated lower UTI, affecting primarily the bladder, is generally oral antibiotics, while the standard treatment for more severe upper UTI usually consists of intravenously administered antibiotics and requires a hospital stay.Yet another approach, known as switch therapy, consists of giving the patient a shot of antibiotics in a doctor's office and then switching to oral antibiotics.After a year's follow-up, 90 scans showed that 29 percent of the patients had kidney scarring, but the damage occurred equally among patients who had either switch or oral therapy. There was no significant difference in cure, re-infection or relapse rates; in the number of patients with fever after 48 hours; or in the number of patients with adverse effects.Available oral antibiotics appear potent enough to treat patients with pyelonephritis efficiently, with no difference in long-term outcomes such as kidney scarring, the review concluded.Nguyen said it might be hard to convince some doctors to prescribe oral therapy for a severe UTI, especially doctors who treat children, since the rate at which children can develop life-threatening complications is often faster than for adults."Children get sicker quicker and if bacteria reach the blood they can easily get sepsis," Nguyen said. "Children are more susceptible to kidney damage and have less resistance to infection. They can worsen in hours. Giving antibiotics intravenously is a practice heavily ingrained in most pediatricians and most physicians will continue to do what they have been taught to do."He added, "Modern-day oral antibiotics are just as effective and quickly absorbed, but some people may not believe they can get into the blood fast enough. More studies may need to be done."
среда, 21 ноября 2007 г.
Most Patients Don't Need Antibiotics Before Dental Procedures
Taking a precautionary antibiotic before a trip to the dentist isn't necessary for most people, and in fact, might create more harm than good, according to updated recommendations from the American Heart Association. The guidelines, published in Circulation: Journal of the American Heart Association, are based on a growing body of scientific evidence weighing the effectiveness of antibiotics against possible risks. The updated recommendations say that only people who are at the greatest risk of bad outcomes from infective endocarditis (IE) -- an infection of the heart's inner lining or the heart valves -- should receive short-term preventive antibiotics before common, routine dental procedures. This includes people with artificial heart valves, a history of previous endocarditis, certain serious congenital heart conditions, and heart transplants patients who develop a problem with a heart valve. For decades, doctors have given short-term antibiotics prior to a dental procedure to many patients with the belief the drugs would prevent IE. As a result, patients with any kind of heart abnormality from mild, symptomless forms of mitral valve prolapse (MVP) to serious congenital birth defects have been instructed to take an antibiotic prior to dental work, even teeth cleaning. However, the drugs carry risks, including fatal allergic reactions and possibly making the bacteria that cause IE to become resistant to antibiotics. Although allergic reactions are minimal, new evidence shows the risks outweigh the benefits for most patients receiving these antibiotics. "We've concluded that if giving prophylactic antibiotics prior to a dental procedure works at all -- and there's no evidence that it does work -- we should reserve that preventive treatment only for those people who would have the worst outcomes if they get IE. That's a profound change from previous recommendations," said Walter R. Wilson, M.D., a professor of medicine at the Mayo Clinic in Rochester, Minn., and chair of the writing group. The new recommendations apply to such common dental procedures as teeth cleaning and extractions. They are based on a comprehensive review of published studies that suggests IE is more likely to occur from bacteria that enter the bloodstream as a result of everyday activities than from a dental procedure. The statement cites a 1999 study estimating that tooth brushing twice a day for a year carried a 154,000 times greater risk of exposure to blood-borne bacteria than a single tooth extraction, the dental procedure reported to be the most likely to cause a bacterial infection. The writing group found no compelling evidence that antibiotic prophylaxis prior to a dental procedure prevents IE in individuals who are at risk of developing this infection. "In fact, maintaining good oral health and hygiene appears to be more protective than prophylactic antibiotics," Wilson said. "This changes the whole philosophy of how we have constructed these recommendations for the last 50 years. Rather than based on the risk of getting IE, they're based on the risk of which patients would have the worst outcome from the infection." Wilson said it's difficult to estimate the number of people affected by the new guidelines. Measurements of the prevalence of mitral valve prolapse range from less than 2 percent to almost 20 percent of the population. According to American College of Cardiology/American Heart Association guidelines for the management of patients with valvular heart disease, when using current echocardiographic criteria for diagnosing MVP, the prevalence is 1 percent to 2.5 percent of the population. Even this estimate means millions of people have been taking antibiotics prior to dental procedures. Patients at the greatest danger of bad outcomes from IE and for whom preventive antibiotics prior to a dental procedure are worth the risks include those with: * artificial heart valves * a history of having had IE * certain specific, serious congenital (present from birth) heart conditions, including * unrepaired or incompletely repaired cyanotic congenital heart disease, including those with palliative shunts and conduits * a completely repaired congenital heart defect with prosthetic material or device, whether placed by surgery or by catheter intervention, during the first six months after the procedure * any repaired congenital heart defect with residual defect at the site or adjacent to the site of a prosthetic patch or a prosthetic device * a cardiac transplant which develops a problem in a heart valve. "Except for the conditions listed above, antibiotic prophylaxis is no longer recommended for any other form of congenital heart disease," the statement said. "These new recommendations are a major change that has evolved over nearly 50 years," said Michael Gewitz, M.D., chair of the AHA Rheumatic Fever, Endocarditis and Kawasaki Disease Committee, a co-author of the guidelines and professor of pediatrics at New York Medical College and Physician-in-Chief for Maria Fareri Children's Hospital at Westchester Medical Center in Valhalla, N.Y. "Over this time, patients with common heart conditions were told they needed to take antibiotics prior to a dental procedure. Now, they'll be told they no longer need them. This will likely cause anxiety and concern in patients and health care providers." Gewitz says this is especially true for the millions of people, young and old, affected with congenital heart diseases. "There is likely to be some confusion until dentists and primary care doctors, and even specialists, all hear about these changes and get used to them," he said. "Since patients with congenital heart disease can have complicated circumstances, even after surgical or other treatment, families and primary care doctors should check with their cardiologist if there is any question at all as to which category best fits the individual patient." He added that patients and their families should ask careful questions of their providers anytime antibiotics are suggested before a medical or dental procedure. They should also be aware that overuse of antibiotics many times can lead to a worse outcome than if they were not used at all. Wilson acknowledged that patients and health care professionals may take awhile to get used to the new guidelines. Many dentists and physicians are used to prescribing the drugs to any patient with any possibility of a heart abnormality, no matter how slight. Likewise, many patients are used to taking the antibiotics, which provide a sense of security, he said. The guidelines say patients who have taken prophylactic antibiotics routinely in the past but no longer need them include people with: * mitral valve prolapse * rheumatic heart disease * bicuspid valve disease * calcified aortic stenosis * congenital heart conditions such as ventricular septal defect, atrial septal defect and hypertrophic cardiomyopathy. "These patients still have a lifelong risk of IE," Wilson said. "We're just saying that the risk is much greater from a random blood-borne bacterial infection resulting from everyday activities than from a dental or medical procedure." The guidelines also do not recommend any prophylactic antibiotics to prevent IE for common gastrointestinal procedures or procedures on the urinary tract. This holds true even for patients with the highest risk of bad outcomes from IE, Wilson said the revised guidelines were prompted in part by the growing body of scientific research that raised questions about the usefulness of widespread prophylactic antibiotic use. The new recommendations are also more in line with international practice. "Over the years, a number of publications have called into question the rationale and efficacy of prophylaxis," he said. "We did a very thorough search of the literature and assembled the world's experts on endocarditis and we based our conclusions on evidence-based medicine."
вторник, 28 августа 2007 г.
Scientists Studying Bacteria And Antibiotics At The Atomic Level See Potential To Create Antibiotics Less Vulnerable To Resistance
A new understanding of an enzyme important for the transfer of genetic information in bacteria may help scientists improve current antibiotics and also create antibiotics that are less vulnerable to resistance. Researchers used extremely powerful imaging techniques to see, for the first time, exactly what happens between bacteria and antibiotics at the atomic level. They report their findings in two studies in the journal Nature. The work provides the most detailed view yet of an enzyme structure that is key to turning on the genes that make bacteria work, said Irina Artsimovitch, a co-author on both studies and an associate professor of microbiology at Ohio State University. Artsimovitch worked with Dmitry Vassylyev, the lead author of both studies and a professor of biochemistry and molecular biology at the University of Alabama at Birmingham. The two conducted the study with researchers from the University of Alabama at Birmingham , the University of Wisconsin-Madison and the University of Nebraska Medical Center. In the first study, the team found that they could create a detailed image of the elongation complex, a structure formed by RNA polymerase. RNA polymerase is the enzyme responsible for setting gene expression in motion, a process called transcription. Without a properly functioning RNA polymerase, a cell will die. "RNA polymerase spends most of its working hours as the elongation complex," Artsimovitch said. "The complex makes RNA's messages one step at a time, many thousands of times, until its completion. "This structure is important from a physiological point of view, not only for antibiotic design, but also because faults in the complex have been implicated in many diseases such as hereditary cancers." Artsimovitch and her colleagues used the bacterium Thermus thermophilus to run their experiments. While T. thermophilus won't make a human sick, the bacterium is widely used to gather structural information at the molecular level. The researchers first isolated the RNA polymerase from T. thermophilus. They then created an active elongation complex by mixing the enzyme with small molecules of DNA and RNA. This solution hardened into a crystal, which the researchers could then examine using an imaging technique called X-ray crystallography. X-ray crystallography let them create a computerized image showing the minute details of the elongation complex. In the second study, the team learned how the antibiotic streptolydigin blocks transcription. Streptolydigin has been around for several decades and the researchers already knew that this antibiotic stops RNA polymerase activity inside a cell. But they didn't know what controlled this mechanism. "We have to know what we're looking at -- and working with -- before it's possible to make a useful antibiotic," Artsimovitch said. "Now we can. Now we can see where the enzyme and antibiotic make contact at the atomic level." Upon examining the X-ray images, the researchers found that the antibiotic prevented the normal operation of the elongation complex by freezing it in the inactive state. They saw a loop-shaped element that must close every time the elongation complex adds a nucleotide (a building block of DNA or RNA) to the growing RNA chain. This loop must open again to allow the next cycle to happen. If something such as an antibiotic keeps the loop from closing, RNA polymerase can't properly function and stalls. "This loop is a target for antibiotics, including streptolydigin," Artsimovitch said. "If we can design new drugs that will prevent its movements, then we will immediately stop the action of RNA polymerase, and bacteria will die soon thereafter." The team's findings may be applicable to realms outside microbiology and drug discovery. Such a clear picture of the RNA polymerase elongation complex may be useful to a number of research areas, including manipulating the complex to increase the efficiency of bacteria that can harvest biofuels, Artsimovitch said. "We think that this mobile loop is a hot spot for regulating transcription in all living organisms, not only by using antibiotics but also by manipulating cellular factors," she said.
понедельник, 27 августа 2007 г.
Foreclosure’s building problem
She wasn't an investor. She didn't have a subprime mortgage. But when Jordan Fogal's house became uninhabitable, the 62-year-old grandmother says foreclosure became her best alternative.
Fogal's troubles began when she and her 72-year-old husband, Bob, moved to a new housing development near Houston in 2002. That first night in the new house, the dining room ceiling collapsed. Bob had pulled the plug in the Jacuzzi tub upstairs, and 100 gallons of water came crashing through the ceiling downstairs because the plumbing drains were not connected.
"That was a preview of coming attractions," Fogal says. Later, the roof and windows leaked, the yard flooded, the shower walls started bowing out, the floor in the kitchen started sinking, and mold began to grow all over the house. The smell was terrible, she recalls, and eventually Fogal's doctor ordered her to leave the house because of the dangerous mold levels. A construction company hired by the Fogals estimated that it would take $150,000 to repair everything. "I could afford my mortgage payment, but I couldn't afford $150,000 in repairs," says Fogal, who had a 30-year fixed-rate mortgage at the time. The home — appraised at $408,000 the day the couple bought it — ended up selling for $234,000 at a foreclosure auction.
"All of this time, I was begging the builder to fix these problems," Fogal recalls. But, she says, they only showed up to about 25% of the appointments she made. "That's absolute nonsense," says Tom Thibodeau, president of Tremont Homes and then-president of the Fogal home's builder, Tremont Custom Construction. "We tried everything we could to fix this house, and she refused it. She only wanted us to buy the house back."
The only original problem with the Fogals' house, Thibodeau says, was a roof leak that was neglected and led to a myriad of other problems. "She would like everyone to believe the house was foreclosed on because of the defect," he says. "But by neglect, she let the leak go and other problems manifested from the leak."
More than a subprime problem?Fogal's case is not an isolated incident. Greg Cole, a homeowner in Georgia who runs a gripe site at georgiamoldhome.com, says he is on the brink of foreclosure after dealing with structural problems and leaks that have led to elevated mold levels. He, his wife, and his two children now take antibiotics every day, he says, because of the high level of mycotoxins — a toxin produced by fungi — in their blood. Elizabeth Dziedzic, a Realtor in Orange Park, Fla., says the deficiencies in her home make it impossible to sell for the amount it would take to pay off her mortgage balance. "There are only few events that are as devastating to a family as the loss of the family home to foreclosure," she says. "I guess this would be a price my family will pay for trying to achieve the American dream."
Foreclosures are up 93% from last year, according to Irvine, Calif.-based Web site RealtyTrac. At the same time, questions are arising as to whether construction quality suffered as homebuilders worked at lightning-fast speed to keep up with demand during the housing boom. It has become increasingly common for homeowners across the U.S. to share personal stories about defective construction through Web sites and blogs.
Everything you read says that the rise in foreclosure has to due with subprime lending," says Nancy Seats, president of Homeowners Against Deficient Dwellings, a nonprofit consumer protection group for homeowners dealing with defective construction. "But [defective construction] absolutely has something to due with the rise in foreclosures. There were absolutely investors that pushed up the price of housing, but there is no question that there are home buyers that were taken in and scammed big-time."
Why not just sue your builder when an irreparable problem arises? Homeowners usually don't have the right to. Most new-home sales contracts state that the customer must go through arbitration before they can even think about bringing their complaint to court.
Fogal's troubles began when she and her 72-year-old husband, Bob, moved to a new housing development near Houston in 2002. That first night in the new house, the dining room ceiling collapsed. Bob had pulled the plug in the Jacuzzi tub upstairs, and 100 gallons of water came crashing through the ceiling downstairs because the plumbing drains were not connected.
"That was a preview of coming attractions," Fogal says. Later, the roof and windows leaked, the yard flooded, the shower walls started bowing out, the floor in the kitchen started sinking, and mold began to grow all over the house. The smell was terrible, she recalls, and eventually Fogal's doctor ordered her to leave the house because of the dangerous mold levels. A construction company hired by the Fogals estimated that it would take $150,000 to repair everything. "I could afford my mortgage payment, but I couldn't afford $150,000 in repairs," says Fogal, who had a 30-year fixed-rate mortgage at the time. The home — appraised at $408,000 the day the couple bought it — ended up selling for $234,000 at a foreclosure auction.
"All of this time, I was begging the builder to fix these problems," Fogal recalls. But, she says, they only showed up to about 25% of the appointments she made. "That's absolute nonsense," says Tom Thibodeau, president of Tremont Homes and then-president of the Fogal home's builder, Tremont Custom Construction. "We tried everything we could to fix this house, and she refused it. She only wanted us to buy the house back."
The only original problem with the Fogals' house, Thibodeau says, was a roof leak that was neglected and led to a myriad of other problems. "She would like everyone to believe the house was foreclosed on because of the defect," he says. "But by neglect, she let the leak go and other problems manifested from the leak."
More than a subprime problem?Fogal's case is not an isolated incident. Greg Cole, a homeowner in Georgia who runs a gripe site at georgiamoldhome.com, says he is on the brink of foreclosure after dealing with structural problems and leaks that have led to elevated mold levels. He, his wife, and his two children now take antibiotics every day, he says, because of the high level of mycotoxins — a toxin produced by fungi — in their blood. Elizabeth Dziedzic, a Realtor in Orange Park, Fla., says the deficiencies in her home make it impossible to sell for the amount it would take to pay off her mortgage balance. "There are only few events that are as devastating to a family as the loss of the family home to foreclosure," she says. "I guess this would be a price my family will pay for trying to achieve the American dream."
Foreclosures are up 93% from last year, according to Irvine, Calif.-based Web site RealtyTrac. At the same time, questions are arising as to whether construction quality suffered as homebuilders worked at lightning-fast speed to keep up with demand during the housing boom. It has become increasingly common for homeowners across the U.S. to share personal stories about defective construction through Web sites and blogs.
Everything you read says that the rise in foreclosure has to due with subprime lending," says Nancy Seats, president of Homeowners Against Deficient Dwellings, a nonprofit consumer protection group for homeowners dealing with defective construction. "But [defective construction] absolutely has something to due with the rise in foreclosures. There were absolutely investors that pushed up the price of housing, but there is no question that there are home buyers that were taken in and scammed big-time."
Why not just sue your builder when an irreparable problem arises? Homeowners usually don't have the right to. Most new-home sales contracts state that the customer must go through arbitration before they can even think about bringing their complaint to court.
суббота, 25 августа 2007 г.
"Wait-And-See" Approach For Treating Ear Infections Substantially Reduces Use Of Antibiotics
For children with acute ear infections seen in an emergency department, giving parents the option of delaying use of antibiotics resulted in significantly lower use of antibiotics compared to parents who received a standard prescription, with little difference in the outcomes for the children, according to a study in the September 13 issue of JAMA. Acute otitis media (AOM; ear infection) is the most common reason for which an antibiotic is prescribed to children. Treatment of AOM accounts for an estimated 15 million antibiotic prescriptions written per year in the United States, according to background information in the article. Untreated AOM has a high rate of natural resolution, with similar rates of complications whether antibiotics are prescribed or withheld. Resistance to antibiotics is a major public health concern worldwide and is associated with the widespread use of antibiotics. David M. Spiro, M.D., M.P.H., formerly of the Yale University School of Medicine, New Haven, Conn., and colleagues conducted a study to determine whether treatment of AOM using a "wait-and-see prescription" (WASP) significantly reduced use of antibiotics compared with a "standard prescription" (SP), and evaluated the effects of this intervention on clinical symptoms and adverse outcomes. Overall, 283 children with AOM aged 6 months to 12 years seen in an emergency department were randomly assigned to receive either a WASP (n = 138) or a SP (n = 145). All patients received ibuprofen and ear analgesic drops for use at home. Phone interviews were conducted after enrollment to determine outcomes. The trial was conducted between July 2004 and July 2005. The researchers found that the WASP significantly reduced the use of antibiotics. Substantially more parents in the WASP group did not fill the antibiotic prescription, compared to the SP group (62 percent vs. 13 percent). There was no statistically significant difference between the groups in the frequency of subsequent fever, otalgia (ear ache), or unscheduled visits for medical care. The patients in the WASP group whose parents filled the prescription reported they did so because of fever (60 percent), otalgia (34 percent), or fussy behavior (6 percent). No serious adverse events were reported for patients in the study. "This randomized controlled trial has provided evidence that the WASP strategy significantly reduces the use of antibiotics in an urban population presenting to an emergency department and may be an alternative to routine treatment of AOM with antibiotics. Wait-and-see prescriptions remain controversial as most pediatricians in the United States have been trained to routinely prescribe antibiotics for AOM and believe that many parents expect a prescription; a small minority of practitioners who care for children routinely use watchful waiting. "The WASP approach may interrupt the cycle of antibiotic prescription, the expectation of parents to immediately treat AOM with an antibiotic, and subsequent medical visits for this illness. The risks of antibiotics, including gastrointestinal symptoms, allergic reactions, and accelerated resistance to bacterial pathogens must be weighed against their benefits for an illness that, for the most part, is self limited. The routine use of WASP for AOM will reduce both the costs and adverse effects associated with antibiotic treatment and should reduce selective pressure for organisms resistant to commonly used antimicrobials," the authors conclude.
пятница, 24 августа 2007 г.
Research May Lead To New Classes Of Antibiotics
Scientists have what could be some very bad news for disease-causing bacteria. All three major classes of antibiotics that kill infectious bacteria do so in part by ramping up the production of harmful free radicals, researchers report in Cell a publication of Cell Press. Because those different types of antibiotics each initially hit different targets, it had been believed they worked by independent means. The findings could point the way to new classes of antibiotics and to a common method by which existing antibiotics could be made to stamp out bacteria even better, according to the Boston University researchers. Such advances are particularly critical at a time when, according to the Centers for Disease Control and Prevention, nearly all significant bacterial infections in the world are becoming resistant to the most commonly prescribed antibiotic treatments. "Hydroxyl radicals damage DNA, which turns on the S.O.S. repair response," said James Collins. "Therefore, our findings suggest that if you could shut off the bacteria's repair response, you might make all bactericidal antibiotics more effective and effective at lower doses. You could in essence create a super-Cipro, super-mycins, and so on." Current antimicrobial therapies fall into two general categories: (1) bactericidal drugs, which kill bacteria with almost complete efficiency, and (2) bacteriostatic drugs, which inhibit their growth, allowing the immune system to clear the infection, Collins's group explained. The targets of bactericidal antibiotics are well studied and predominantly fall into three classes: (1) those that hit DNA, (2) those that hit proteins, and (3) those that hit the bacterial cell wall. In contrast, most bacteriostatic drugs work by blocking the function of ribosomes, which are the sites of protein synthesis. While antibiotics' ability to kill bacteria had been attributed solely to those class-specific drug-target interactions, "our understanding of many of the bacterial responses that occur as a consequence of the primary drug-target interaction remains incomplete," the researchers said. Collins and his colleagues recently uncovered some evidence that at least some antibiotics might have some other deadly tricks. They showed that one type of antibiotics, including quinolones, which block DNA's replication and transcription into messenger RNA, also causes a breakdown that leads to the production of free radicals. Moreover, they found that those highly reactive chemicals help finish the bacteria off. In the new study, the researchers wanted to know whether other antibiotics also drive the toxic brew. Indeed, they show, drugs that kill bacteria all do cause a rise in free radicals, and all in the same manner. This is not so for drugs that only stunt bacteria's growth, they report. "The ever-increasing prevalence of antibiotic-resistant strains has made it critical that we develop novel, more effective means of killing bacteria," the researchers concluded. "Our results indicate that targeting bacterial systems that remediate hydroxyl radical damage, including proteins involved in triggering the DNA damage response… is a viable means of potentiating all three major classes of bactericidal drugs. Moreover, pathway analyses and systems biology approaches may uncover druggable targets for stimulating hydroxyl radical formation, which could result in new classes of bactericidal antibiotics."
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