A 'superbug' which can cause life-threatening and disfiguring infections is being discovered in the gay communities of San Francisco, Boston, New York and Los Angeles, and researchers are worried its spread may soon be out of control.
Methicillin-resistant Staphylococcus aureus, or MRSA, is being transmitted among gay men during sex, and sexually active gay men in San Francisco are 13 times more likely to be infected than their heterosexual neighbours, the researchers reported this week in the Annals of Internal Medicine.
"Once this reaches the general population, it will be truly unstoppable," said Binh Diep, a researcher at the University of California, San Francisco who led the study. "That's why we're trying to spread the message of prevention."
The superbug can cause life-threatening and disfiguring infections and can often only be treated with expensive, intravenous antibiotics.
It killed about 19,000 Americans in 2005, most of them in hospitals, according to a report published in October in the Journal of the American Medical Association. At least two cases have so far been diagnosed in the UK, according to Channel 4 News.
Staph infections often look like raised red dots on the skin. Left untreated, the areas can swell and fill with pus.
About 30% of all people carry ordinary staph chronically. It can be passed by touching other people or by depositing the bacteria on surfaces or objects.
The bacteria can cause deep-tissue infections if they enter the body through a wound in the skin.
Of those people who carry staph, most carry it in their noses but community-based MRSA also can live in and around the anus and is passed between sexual partners.
Incidence of MRSA is rising along with the resurgence of syphilis, rectal gonorrhea, and new HIV infections partly because of changes in beliefs about the severity of HIV and an increase in risky behaviors, such as illicit drug use and having sex that abrades the skin, Diep's team wrote.
"Your likelihood of contracting each of these diseases increases with the number of sexual partners that you have," Diep explained. "The same can probably be said for MRSA."
The best way to avoid infection is by washing hands or genitals with soap and water, Diep said.