A new study from the Annals of Internal Medicine is showing that a highly drug-resistant strain of multidrug-resistant, community-associated, methicillin-resistant Staphylococcus aureus (MRSA) is being spread among gay men in San Francisco and Boston.

Local health officials say they have not seen evidence of the multi-drug resistant MRSA in the Nashville area, but cautioned those who travel frequently.

“MRSA skin infections have become very common all across the US, but this is the first report that gay men might be at higher risk – at least in San Francisco,” said William Schaffner, M.D., professor and chair of the department of Preventive Medicine at Vanderbilt University Medical Center and a leading expert on infectious diseases.

Schaffner said that while the study used “admittedly imprecise” calculations showing gay men in San Francisco have a higher rate of MRSA skin infections than the general population, it was concerning that multi-drug resistant MRSA strains were being seen in San Francisco.

“We’ve, fortunately, not seen this here (yet),” he said. “The study seems to indicate that this is distinctive among gay men. That it has been seen both in San Francisco and Boston is disquieting – clearly the bug could spread elsewhere because people travel frequently. This would be a very bad thing, indeed.”

The researchers also seemed to be concerned about rapid spread, writing in the study that it "has the potential for rapid, nationwide dissemination" among gay men.

The population-based survey and cross-sectional study was done using chart review on patients in nine hospitals in San Francisco (population-based survey) and two outpatient clinics in San Francisco and Boston. It showed that the MRSA bacteria seemed to be spread most easily through anal intercourse but also through casual skin-to-skin contact and touching contaminated surfaces.

“In San Francisco, multidrug-resistant USA300 manifested most often as infection of the buttocks, genitals, or perineum,” wrote researchers in the study. “In Boston, multidrug-resistant USA300 was recovered exclusively from men who have sex with men.”

“I've not heard anything about an increase in MRSA in gay men in particular, let alone the apparent resistance to the three drugs discussed in the study,” said Brad Beasley, Metro Health Department's director of STD/HIV Prevention and Control. “The resistance is scarier than the population trend, at least for the moment.”

Beasley said scrubbing with soap and water might be the most effective way to stop skin-to-skin transmission, particularly after sexual activities.

“Many folks harbor the bacteria naturally, usually in the nostril, but it is also found on the skin,” he said. “Consistent, good hygiene will help reduce the chances of developing a sore. So when that hot, sweaty session is over, everyone should head to the showers.”

And, he said, “change the sheets, too.”

The study said that the MRSA that infected the gay men was spread by skin contact, causing abscesses and infection in the buttocks and genital area. The new strain is known as MRSA USA300. The strain is much more difficult to treat because it is resistant not just to methicillin, but also many more of the antibiotics used to treat the earlier strains.