MRSA (Mersa, Staph) Questions

MRSA has creeping resistance to key drugs

Link: HighWire Press -- Medline Abstract.

Methicillin-resistant Staphylococcus aureus (MRSA) isolates (n = 3,189) from 2,990 patients were investigated by agar screening and by the E-test(TM) macromethod for reduced susceptibility to glycopeptide. No vancomycin-resistant S. aureus or glycopeptide-intermediate S. aureus (GISA) were detected but 178 isolates were confirmed as hetero-GISA (hGISA) by vancomycin population analysis profile (PAP)-area under the curve (vPAP-AUC) ratio determination and/or teicoplanin PAP (tPAP) methods. Of 139 isolates detected using the recommended E-test(TM) macromethod cut-off values of >/=8 mg/L for both vancomycin and teicoplanin or >/=12 mg/L for teicoplanin alone, 73 were confirmed as hGISA by vPAP-AUC, 95 by tPAP and 108 by both methods.

Antibiotic Resistance: Doctors' Antibiotic Prescribing Practices Still Contributing To Problem

Link: ScienceDaily: Antibiotic Resistance: Doctors' Antibiotic Prescribing Practices Still Contributing To Problem.

General practitioners are still prescribing antibiotics for up to 80% of cases of sore throat, otitis media, upper respiratory tract infections, and sinusitis, despite the fact that official guidance warns against this practice, according to an analysis of the world's largest primary care database of consultations and prescriptions, published in a supplement to the Journal of Antimicrobial Chemotherapy. Although prescriptions of antibiotics for respiratory tract infections declined during the 1990s, GPs still continue to prescribe antibiotics for a high proportion of infections even if the causes of the symptoms are likely to be viral. And this practice is hindering efforts to prevent the spread of antibiotic resistance

Multi drug resistant MRSA noted in India

Link: HighWire Press -- Medline Abstract.

We report the prevalence of methicillin resistant Staphylococcus aureus (MRSA) infections and their antibiotic susceptibility pattern in our hospital located in eastern Uttar Pradesh. Out of total 549 strains of Staphylococcus aureus isolated from different clinical specimens 301 (54.85%) were found to be methicillin resistant. More than 80% of MRSA were found to be resistant to penicillin, cotrimoxazole, ciprofloxacin, gentamicin, erythromycin, tetracycline, 60.5% to amikacin and 47.5% to netilmicin. However, no strains were resistant to vancomycin. Many MRSA strains (32.0%) were multi-drug resistant. To reduce the prevalence of MRSA, the regular surveillance of hospital associated infection, monitoring of antibiotic sensitivity pattern and formulation of definite antibiotic policy may be helpful.

Antibiotics are over prescribed

Link: Prescribing of Antibiotics to Children Still at a Level to Cause Drug Resistance, Experts Warn.

Regular prescribing of antibiotics to children in the community is sufficient to sustain a high level of antibiotic resistance in the population, warn experts in a study published on bmj.com today. UK general practitioners are strongly encouraged to reduce antibiotic prescribing to minimize the risk of drug resistance, yet prescribing antibiotics to children remains common practice, write David Mant and colleagues at the University of Oxford. A paper published in 1999 reported that 55 percent of children aged 0-5 years in the UK (the group of patients who receive most antibiotics in the community) receive an average of 2.2 prescriptions for a �-lactam antibiotic like amoxicillin from their general practitioner each year. Although a reduction in prescribing (and the strategy of recommending a 24- to 48-hour delay before filling antibiotic prescriptions) has probably resulted in about a 40 percent decrease in consumption since then, unpublished data suggest that community antibiotic prescribing is again rising, they say. This week's BMJ also reports on a study showing that UK GPs are still prescribing antibiotics for a large proportion of patients with minor infections, despite national guidance. So they set out to assess the effect of antibiotic prescribing on antibiotic resistance in individual children in primary care.

VISA mutating and resisting daptomycin?

Link: Characterization of daptomycin nonsusceptible vancomycin-intermediate Staphylococcus aureus in a patient with endocarditis -- Julian et al., 10.1128/AAC.00559-07 -- Antimicrobial Agents and Chemotherapy.

New Way To Target And Kill Antibiotic-Resistant Bacteria Found

Link: New Way To Target And Kill Antibiotic-Resistant Bacteria Found.

Putting bacteria on birth control could stop the spread of drug-resistant microbes, and researchers at the University of North Carolina at Chapel Hill have found a way to do just that. The team discovered a key weakness in the enzyme that helps "fertile" bacteria swap genes for drug resistance. Drugs called bisphosphonates, widely prescribed for bone loss, block this enzyme and prevent bacteria from spreading antibiotic resistance genes, the research shows. Interfering with the enzyme has the added effect of annihilating antibiotic-resistant bacteria in laboratory cultures. Animal studies of the drugs are now underway. "Our discoveries may lead to the ability to selectively kill antibiotic-resistant bacteria in patients, and to halt the spread of resistance in clinical settings," said Matt Redinbo, Ph.D., senior study author and professor of chemistry, biochemistry and biophysics at UNC-Chapel Hill.

Hospitals fighting a war they cant win

Link: Hospital infection info is scarce.

Hospitals are fighting a war they can't win when they take on hospital-acquired infections, said Dr. Mark Dowell, infectious disease physician in Casper. But, he said, Wyoming health care providers must hit "the battlefield" every day to try to prevent as many infections as possible. "It’s tough," said Dowell, head of infection control at the Wyoming Medical Center. "Every time we create a new antibiotic, the bugs find a way around it. If we are not aggressive every day, the day will come when we have organisms we can’t treat."

Doctors alarmed at drug resistance patterns

Link: The Winnipeg Free Press Online Edition.

Zhanel and his colleagues are studying the genetics of superbugs and how they are able to resist up to five classes of different antibiotics -- including penicillin, streptomycin and erythromycin. He'll discuss some of his findings at a public lecture, called Superbugs: Are we Doomed?, at the University of Manitoba Tuesday night. While researchers first believed bacteria were only passing drug-resistant genes to their immediate offspring, Zhanel said new DNA studies are proving bacteria have figured out how to "one-up" both antibiotics and the body's immune system. Superbugs carry a cluster of genetic codes to resist antibiotics, and can freely make copies of these codes to share with all of the body's bacteria. Zhanel said that means a drug-resistant skin infection can quickly spread to other parts of the body, including the lungs and the blood.

Resistance patterns emerge in new study

Link: Haber Saglik

Scientists studied two antibiotics commonly used to treat lung infections, clarithromycin and azithromycin. They found that both drugs significantly increased numbers of antibiotic-resistant streptococci bacteria in 148 healthy volunteers' mouths. Advertisement Azithromycin was the quickest to provoke resistance, the researchers, including Stephanie Dancer, from the Southern General Hospital in Glasgow, reported in the Lancet medical journal. However, clarithromycin induced a powerful form of resistance. The drugs belong to a family of broad-spectrum antibiotics called macrolides which are derived from soil bacteria and are used to treat many infections. The researchers found that the effect of a single course of antibiotics on natural non-harmful mouth bacteria lasted more than 180 days. Such bugs could serve as a reservoir of resistance-conferring genes that might be passed on to potentially dangerous bacteria, they said. The team, led by Herman Goossens, from the University Hospital Antwerp in Belgium, wrote: "Macrolide use is the single most important driver of the emergence of macrolide resistance in vivo (outside the laboratory) Physicians should take into account the striking ecological side effects of antibiotics." Dr Dancer commented: "The key message is that antibiotic prescribing affects the patient, their environment, and all the people that come into contact with that patient or with their environment.

Experts: Chatter key to fight superbugs

Link: Experts: Chatter key to fight superbugs - USATODAY.com.

Do germs communicate? Many scientists think so and are betting the chatter may hold the key to developing the next generation of drugs to fight killer superbugs. The conventional wisdom has long been that the carpet-bombing approach is the best way to fight infection. But as evidence of bacterial bonding has mounted in the past decade, researchers are now focusing on antibiotics that will break down the lines of communication. In the last 20 years, the number of scientists working in this field has jumped from a few solitary researchers to thousands. In Britain, the strategy is one of the top research priorities of a newly formed center dedicated to stopping superbugs. "Bacteria are a bit like an army going into battle," said Dr. Paul Williams, professor of molecular biology at the center at Nottingham University. "Only when they've got strength in numbers do they tell their troops to start firing." The thinking is that if bacterial communication can be interrupted, the microbes might be incapacitated before doing any damage. And by not killing off the bacteria, they won't have the Darwinian opportunity to evolve into resistant strains.