BETHESDA, MD. — Community-associated methicillin-resistant Staphylococcus aureus infections in gay men might be associated with drug use and low levels of hygiene, especially after having sex.
Based on reports from a commercial laboratory that handles about half of the cases sent to the bureau of communicable diseases at the New York City Department of Health and Mental Hygiene, Melissa A. Marx, Ph.D., and her colleagues identified 188 men who have sex with men (MSM) with CA-MRSA infections out of 2,813 patients from New York who had S. aureus skin infections during April 2005 to September 2007.
In the first year of the study, Dr. Marx and her colleagues conducted telephone interviews with the 188 men using a structured questionnaire. After the first year, the researchers interviewed 195 MSM patients to serve as controls. They had been diagnosed with amebiasis or giardiasis during July 2006 to October 2007. These gastrointestinal infections are found commonly in MSM because of sexual transmission, said Dr. Marx, director of the department's antibiotic resistance unit.
Patients in the control group were more likely to be non-Hispanic white, but the overall profile of both groups was a “white, educated [resident of] Manhattan, [an] affluent community in New York City,” Dr. Marx said at an annual conference on antimicrobial resistance sponsored by the National Foundation for Infectious Diseases.
Because the results of laboratory testing for CA-MRSA had not yet been completed, the researchers defined “community-associated” by the patients' lack of exposure during the past 3 months to hospital stays, residence in a long-term care facilities, invasive outpatient procedures, or hemodialysis.
Factors that were significant, independent predictors of CA-MRSA infection included having sex at a private party in the year before infection, routinely waiting more than 30 minutes to wash after sex, physical contact with someone with a skin infection within the past 3 months, having HIV/ AIDS, and crystal methamphetamine use.
Dr. Marx cautioned that the patients in the study were from private physician offices and therefore do not represent patients without insurance who seek care at emergency departments or public clinics.
The goal of the Department of Health and Mental Hygiene's research on risk factors for MRSA in groups at high risk for the condition is to develop “prevention advice and interventions for populations at high risk,” Dr. Marx said. But, “it's been hard to get a hold of what the risk groups are for community-associated MRSA because we've seen outbreaks in communities as diverse as sports participants, inmates, military recruits, men who have sex with men.”
Previous studies of groups at high risk for CA-MRSA showed skin-to-skin infection transmission is affected by crowding, compromised skin, and lack of cleanliness.