Study Finds Bacterial STD Linked to Increased Risk of HIV

SAN FRANCISCO — A common sexually transmitted bacterial infection more than doubles the risk of HIV infection in African women, according to a study by researchers at RTI International.

The study, published in the March 13 issue of AIDS, found that women with the "emerging" sexually transmitted disease Mycoplasma genitalium are more likely to acquire HIV infection.

"Further research will be required to confirm a causal relationship and to identify risk factors for M. genitalium infection in African populations," said Sue Napierala Mavedzenge, Ph.D., a research investigator with the Women's Global Health Imperative at RTI International and the study's lead author. "If findings from this research are confirmed, M. genitalium screening and treatment among women at high risk for HIV-1 infection may be warranted as part of an HIV-1 prevention strategy."

First discovered in 1980, M. genitalium is a bacterial STD that causes inflammatory conditions of the genitals and reproductive tract (urethritis, cervicitis and pelvic inflammatory disease). The infection, which may be present for years without causing any symptoms, can be eliminated with appropriate antibiotics.

This study used data from a larger study of HIV acquisition among young women in Zimbabwe and Uganda to assess the effects of M. genitalium on HIV risk. In the study, 190 women who became infected with HIV during follow-up were matched to women of similar age and risk who did not acquire HIV. Both groups were tested for the presence of M. genitalium, which was evaluated as a risk factor for HIV infection.

In initial samples, when all women were HIV free, infection with M. genitalium was present in about 15 percent of women who later developed HIV versus 6.5 percent in women who remained HIV free. Mycoplasma genitalium was more frequent than other bacterial STDs, including gonorrhea and chlamydia.

The researchers found that after adjustment for other factors, women who initially had M. genitalium were more than twice as likely to become infected with HIV. Certain other STDs were also risk factors for HIV.

The researchers estimated that about 9 percent of all HIV infections occurring in the study were attributable to M. genitalium. However, other factors were more strongly associated with HIV risk, especially the presence of herpes simplex virus 2 (the virus that causes genital herpes) and having a partner with HIV risk factors.