Lactobacillus Viruses May Be Sexually Transmitted

Embargoed until May 31 at 10:30 a.m. C.S.T.

LACTOBACILLUS VIRUSES MAY BE SEXUALLY TRANSMITTED: UIC STUDY Vaginal condition more prevalent and serious than yeast infection

Bacterial vaginosis, a condition that can lead to serious health complications in women, may be caused by a sexually transmitted virus that infects vaginal lactobacilli, according to a University of Illinois at Chicago study.

Although it is more common and more serious than yeast infection, bacterial vaginosis receives less attention and, as a result, fewer women are aware of it.

The vagina normally contains high amounts of helpful bacteria called lactobacilli, which play an important role in maintaining vaginal health. During bacterial vaginosis (BV), an unexplainable decrease of lactobacilli occurs, exposing women to several health risks.

In the UIC study, Sylvia Pavlova, senior research specialist, and Lin Tao, associate professor of oral biology, discovered the first evidence that viruses may be implicated as a cause for bacterial vaginosis and that the agent is sexually transmitted. The results will be presented at the 99th General Meeting of the American Society for Microbiology in Chicago on Monday, May 31.

Lactobacilli, when normally present in the vagina, produce hydrogen peroxide and lactic acid, creating an acidic environment that harmful bacteria and HIV find hostile. When bacterial vaginosis occurs it can increase the pH level, making the environment more hospitable to organisms that cause sexually transmitted diseases. Women who suffer from bacterial vaginosis are also at an increased risk for pelvic inflammatory disease, pre-term delivery of low birth weight infants and contracting HIV infection through heterosexual contact.

The cause of bacterial vaginosis is unknown, but it primarily affects women who are sexually active. Bacterial vaginosis is the most prevalent cause of vaginal discharge and malodor; however, half of women who have bacterial vaginosis are asymptomatic. Although more studies need to take place to fully understand the causes of bacterial vaginosis, the infection of lactobacilli with viral pathogens and their subsequent depletion may be a significant factor.

Also participating in the study were Ali Kilic of Turkey's Karadeniz Technical University and Jill Clarridge of Baylor College of Medicine in Houston. The research was supported by grants from the National Institutes of Health, Concerned Parents for AIDS Research-AmFAR, and the UIC Center for Research on Women and Gender.

Among 67 virus-infected vaginal Lactobacillus strains isolated from 207 American and Turkish women, researchers selected five strains in two groups. The first group included two Lactobacillus strains from an American woman. The second group included three strains from three unrelated Turkish women. Electron microscopy, host range and DNA fingerprinting were used to study the viruses of these strains. The Lactobacillus host strains were assayed by protein profiles. Additionally, eight Lactobacillus strains isolated from five male urine samples were analyzed.

The results showed the two Lactobacillus strains from the American woman displayed different protein profiles but their viral DNA had an identical pattern, indicating that the same virus infected the two different bacteria. The three Lactobacillus strains from the Turkish women were found through DNA fingerprinting to have identical viruses. Two of these three strains, however, were identical, but the third one was different, suggesting that the virus could be transmitted either as a latent virus in its host bacterium or as a free virus. Among the eight male urinary Lactobacillus strains, two strains from separate samples released viruses that killed eight and 11 of 30 vaginal Lactobacillus strains respectively.

The researchers concluded that viruses could infect lactobacilli in the vagina, be transmitted sexually, and male partners could be a source of the virus that is causing the infection.
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