Once confined to hospitals, drug-resistant and potentially deadly staph infections are rising among general population, study finds.
By Charles Piller
Times Staff Writer
April 7, 2005
Drug-resistant staph infections, once largely confined to hospitals, are far more common in the general population than previously thought, according to a study published today in the New England Journal of Medicine.
The study examined more than 1,600 cases of the infection caused by a strain of Staphylococcus aureus in Baltimore, Atlanta and Minnesota. Nearly one-fourth of those patients required hospitalization.
In recent years, the potentially deadly infection has been detected in jail inmates, sexually active gay men and professional athletes.
The latest study, conducted by researchers from the Centers for Disease Control and Prevention and several other institutions, confirmed that the organism was now circulating widely in the general population.
The CDC research found that children younger than 2 were at higher risk, which could be because children get more cuts and scrapes. Blacks in Atlanta were found to be at higher risk than whites, the researchers found.
"There was a remarkable association of a large number of cases, all caused by this drug-resistant strain," said Dr. Henry F. Chambers, a staph expert at San Francisco General Hospital who wrote an editorial accompanying the study.
Common staph is present on the skin or in the nostrils of about one in three people, typically without causing illness.
In previous research, the drug-resistant strain was found to cause painful skin lesions that resembled infected spider bites, a deadly lung disease known as necrotizing pneumonia, and toxic-shock syndrome — a type of blood poisoning that can be fatal.
But doctors outside of hospitals typically don't look for drug-resistant staph, and therefore don't order lab tests to verify the strain. Instead, they routinely prescribe ineffective antibiotics, sometimes leading to more severe illnesses and even deaths.
In a separate article in the journal, researchers reported that they have linked drug- resistant staph infections to a rare, often-deadly disease known as necrotizing fasciitis, or more commonly, "flesh eating" syndrome.
"Necrotizing fasciitis is a terrible disease, but before now, Staph aureus was never the cause," said Dr. Robert Daum, a pediatrics professor at the University of Chicago and one of the first physicians to notice wider circulation of drug-resistant staph.
"Antibiotic resistance and virulence are converging," he said. "It's really disturbing."
Researchers reported 14 Los Angeles cases of necrotizing fasciitis — a fast-spreading infection that kills skin, connective tissue and muscle.
The 14 patients were treated at Harbor-UCLA Medical Center in 2003 and 2004, but had contracted the disease before being admitted to the hospital. All survived, though several required reconstructive surgery. The disease typically kills one-third of its victims.
Most of the patients had risk factors for necrotizing fasciitis, including a history of injected drug use or hepatitis C.
But in an unsettling finding, four victims had no apparent vulnerability.
The few antibiotics that kill the resistant staph strain are costly, and likely to wane in potency over time, said Dr. Loren G. Miller, a researcher at the Los Angeles Biomedical Research Institute, and lead author of the study.
"The problem is we are not developing new antibiotics as fast as we used to because there are very few monetary incentives for pharmaceutical companies to do that," Miller said. "The bugs are about two steps ahead of us."