NEW YORK, Dec 31 (Reuters Health) -- The presence of lactobacilli bacteria
in the vagina may reduce the risk of infection with sexually transmitted
diseases such as HIV and gonorrhea, researchers report.
Lab tests show that lactobacilli produce substances capable of fighting
infection. Strains of lactobacilli appear to "play a pivotal role in controlling
the microenvironment of the vagina," explain American and Kenyan researchers led
by Dr. Joan Kreiss of the University of Washington in Seattle. They report their
findings in the December issue of The Journal of Infectious Diseases.
In their study, Kreiss and colleagues evaluated the relationship between
lactobacilli colonization and infection with HIV and other sexually transmitted
diseases in over 650 HIV-negative sex workers in Mombasa, Kenya. All the women
were studied over a period of about 6 months. The team also assessed the women
for bacterial vaginosis, a disorder where there is a decrease in lactobacilli in
the vagina, but an increase in other bacteria. This disorder had been linked to
pelvic inflammatory disease and increased risk of preterm delivery.
At the beginning of the study, 26% of women tested positive for vaginal
lactobacilli.
Kreiss' team found that women without vaginal lactobacilli were at
"increased risk of acquiring HIV-1 infection and gonorrhea," compared with women
who carried the organism. HIV infection risks seemed particularly low among
women carrying a particular strain of hydrogen peroxide-producing Lactobacillus,
the authors add.
On the other hand, bacterial vaginosis appears to increase susceptibility
to HIV infection, the team report.
Overall, they say, this group of African prostitutes had "extremely low"
levels of lactobacilli compared with women in the general population, but
"extraordinarily high" levels of more harmful organisms, including infection
with bacterial vaginosis.
Based on these findings, Kreiss and colleagues conclude that "the absence
of vaginal lactobacilli may increase the efficiency of male-to-female HIV-1
infection."
Topical drugs containing active lactobacilli are currently under
development. Public health programs providing women at high risk for AIDS access
to these drugs could represent "exciting opportunities for new methods of HIV-1
control," the authors conclude.
