Concern Mounts as Bacteria Resistant to Antibiotics Disperse Widely

A particularly persistent and sometimes deadly bacterial infection known as methicillin-resistant staphylococcus aureus, often abbreviated as M.R.S.A. have health care providers concerned about an increasing number of such cases for years. But they are now reporting infections in unexpected locales and among a bewilderingly diverse population.

M.R.S.A. is also demonstrating an alarming virulence and protean nature, making it more difficult to contain and treat. Doctors say that because it is not clear who is vulnerable — even people who are in good health and practice good hygiene have been infected — everyone should take steps to reduce his or her risk.

Although the bacterium has lurked in hospitals for decades, outbreaks elsewhere were virtually unheard of until the 1990’s. Even then, the incidence was small, and the infection was confined mostly to people with weak immune systems: young children, the elderly and people with H.I.V. It occurred mostly in large metropolitan areas.

But in the last five years, the number of cases has drastically increased. “It’s infecting normal, healthy people everywhere,” said Loren G. Miller, a principal investigator at the Los Angeles Biomedical Research Institute at Harbor-U.C.L.A. Medical Center.

Officials at the CDC have reported that infection rates have doubled since 2002 in cities like Atlanta and Baltimore, where the agency finances disease surveillance.

Staphylococcus aureus can be found almost everywhere: on countertops, in towels and sheets, and on skin. It is harmless until it enters a break in the skin, where it can feed on tissue and multiply. White blood cells often destroy the bacteria. But sometimes, an antibiotic is needed as reinforcement to prevent the microbes from invading the bloodstream and attacking the vital organs.

Methicillin-resistant staphylococcus aureus, the experts say, is undeterred by most frontline antibiotics, and it is rapidly developing resistance to others. The overuse of antibiotics has not helped. That problem, combined with the widespread prophylactic use of antibiotics in livestock, has given staph, not to mention other bacteria, ample opportunity to evolve into superresistant and superpersistent bugs.

“It’s part natural evolution, but we’re speeding it up by our behaviors,” said Nicole Coffin, a spokeswoman for the C.D.C. Unlike the resistant staph seen in hospitals, many of the strains being reported elsewhere can release a toxin, Panton-Valentine leukocidin, or P.V.L., that kills white blood cells.

Also disturbing, doctors say, are infections of resistant staph that mutate into life-threatening necrotizing fasciitis, the so-called flesh-eating bacteria. Such infections had been associated primarily with streptococcal bacteria, which cause strep throat.

M.R.S.A. has also been implicated in fatal cases of meningitis, or swelling of the membranes that cover the brain and spinal cord, and pyomyocitis, which results in abscesses deep in muscle tissue and is more commonly found on tropical islands.

The big questions are why some of those people develop infections and others do not, and why some who are infected become ill or even die while others rapidly recover.

“The short answer is we don’t know,” said Dr. Franklin Lowy, a professor of pathology at the College of Physicians and Surgeons of Columbia University and the lead researcher in a study on the spread of resistant staph financed by the National Institutes of Health.

Failing to wash thoroughly, and sharing razors, towels or sports equipment increases the odds of exposure and infection, experts say. Tattooing and body waxing also make an infection more likely, because needle punctures or vacant hair follicles give the bacteria more portals of entry.

But the bacteria can also creep into a person’s system through an invisible abrasion from shaving or even a mosquito bite. Being infected can be a matter of “plain old bad luck.”

Though cleanliness is a good preventive, washing too frequently can also make someone more susceptible. Bathe obsessively, and “you clear a path for more aggressive bacteria like M.R.S.A. to take hold,” said Dr. Stephen K. Tyring, a professor of dermatology at the University of Texas Health Science Center at Houston.

Research also suggests that antibacterial soap is no more effective than regular soap in killing the bacteria, though alcohol-based sanitizing gels kill more bacteria on the hands than soap.

After an infection has begun, antibiotics like clindamycin, minocycline and vancomycin are effective, but they tend to work slowly and can have side effects like rashes, teeth discoloration and severe diarrhea.

When caught early enough, infectious disease experts said, a staph infection can also be treated by a minor surgical incision to drain the lesions, without resorting to oral or intravenous antibiotics.

It is important to see a doctor when a cut, scrape or bump becomes red, large, painful or purulent. Red lines tracking away from the abscess, as well as a fever, indicate that the infection is severe and needs immediate attention.

Courtesy of NY Times

Bonnie - scary stuff; there is no succinct answer to counteract this; although, keeping your immune system as strong as possible by avoiding high added sugar intake and balanced eating will help.