Drug-resistant bacteria increasingly causing infections in healthy people


An emerging form of so-called "flesh-eating bacteria" is caused by a strain that is resistant to standard first-line antibiotics. The same type of bacteria, methicillin-resistant Staphylococcus aureus (MRSA) is causing record numbers of less-serious skin infections in children and also is emerging as a cause of pneumonia, which can be deadly.

Numerous studies on the rise in infections caused by MRSA among healthy people outside of the hospital nearly unheard of a few years ago are being presented at the 42nd Annual Meeting of the Infectious Diseases Society of America (IDSA).

MRSA is a concern because antibiotics prescribed by physicians only a few years ago typically no longer work. Over time, bacteria can mutate and become resistant to specific antibiotics. Effective antibiotics are available to treat MRSA, but physicians are concerned that the bacteria will eventually become resistant to those as well. Drug-resistant infections have long been a problem in hospitals and among the elderly and chronically ill, but in recent years physicians are seeing these infections more and more in healthy people.

One study being presented at the meeting documents 14 cases of necrotizing fasciitis (known colloquially as the "flesh-eating bacteria") in Los Angeles caused by MRSA, an uncommon cause of the illness. None of the patients died, but all had surgery to remove infected flesh, three needed reconstructive surgery (such as skin grafting) and 10 spent time in the intensive care unit, one for a month. Half originally were thought to have less-serious skin abscesses. Four patients initially were given antibiotics to which the bacteria were resistant, but all 14 patients were eventually successfully treated with the antibiotics vancomycin and/or clindamycin.

Necrotizing fasciitis infections can start in a small cut or trauma and spread throughout the body within hours or days if not treated with surgery and antibiotics. Most cases of necrotizing fasciitis are caused by a different type of bacteria called Group A streptococcus (the same type of bug that causes strep throat) and about a third are fatal.

"This is about as serious an infectious disease emergency as you can get," said Loren G. Miller, MD, MPH, principal investigator at the Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center (LA BioMed), assistant professor of the David Geffen School of Medicine at UCLA, and staff physician at Harbor-UCLA Medical Center, Torrance, Calif. "Thankfully no one died, but physicians need to be aware that if they see cases of necrotizing fasciitis, they should treat for this resistant bug (MRSA) in addition to the other known causes until they know the causative bacterial. This is a major shift in treatment approach.

"We don't know how these people got the infection there doesn't seem to be a common thread," said Dr. Miller. "Four of the people had absolutely no other medical conditions or risk factors."

Copies of 2004 IDSA news releases are available online at www.pcipr.com. For IDSA's report on antibiotic resistance and the drug-development pipeline, visit www.idsociety.org/badbugsnodrugs. A symposium at the meeting will explore the pipeline issues in greater detail from 2 to 4 p.m. Friday, Oct. 1 in Room 302 of the Hynes Convention Center.

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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