- Beneficial bacteria found in healthy women help to reduce
the amount of vaginal HIV among HIV-infected women and might make it more
difficult for the virus to spread, boosting the possibility that "good
bacteria" might someday be tapped in the fight against HIV.
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- The findings come from physicians and scientists at the
University of Washington and the University of Rochester Medical Center,
who worked together in an effort to learn more about how HIV survives and
spreads from person to person. The study involving 57 women was done in
Seattle and Rochester through the Women's HIV Interdisciplinary Network
(WHIN), which is based at the University of Washington.
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- The team studied the vaginal environment, examining the
mix of bacteria that reside there and taking into account several other
factors. Physicians tracked the level of HIV virus in the vagina as well
as infection by common sexually transmitted diseases like trichomoniasis,
gonorrhea and chlamydia, and other more common types of vaginal infections.
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- Physicians also monitored the levels of beneficial bacteria
known as Lactobacillus in the vagina, as well as hydrogen peroxide, which
is produced by the bacteria and hinders the virus. They also measured the
level of HIV in the women's blood and the rate of progression of the disease
overall.
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- The team found that women with hydrogen-peroxide-producing
Lactobacillus in the vagina had lower levels of HIV virus in genital secretions
- what physicians call the genital viral load. Physicians know that the
lower the level of HIV in the sexual tract, the less likely that the virus
will be spread from person to person through sexual contact.
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- Scientists have previously recognized from laboratory
studies that Lactobacillusmight give women some natural protection against
HIV. The bacteria, commonly found in most women, bind to the virus and
secrete hydrogen peroxide. The bacteria are a close cousin of the Lactobacillus
bacteria found in the small intestine, a type of "good" bacteria
widely found in yogurt.
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- While previous work in the laboratory has indicated that
Lactobacillus might help prevent HIV infection in women, the current study
actually links, in women, decreased levels of the virus in the vagina with
the presence of Lactobacillus that produce hydrogen peroxide there.
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- The team also found that the amount of the virus in the
vagina varied in step with the presence of Lactobacillus: Women who did
not have the bacteria at first but who had acquired it by a subsequent
visit had their vaginal HIV levels drop, while vaginal HIV levels increased
in women in whom the good bacteria had disappeared between visits.
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- The research was presented this week at the Conference
on Retroviruses and Opportunistic Infections in Boston by Jane Hitti, M.D.,
associate professor in the Department of Obstetrics & Gynecology at
the University of Washington School of Medicine. Hitti has been working
closely withRobert Coombs, M.D., Ph.D., the principal investigator for
the WHIN study and professor of Laboratory Medicine and of Medicine at
the University of Washington. Amneris Luque, M.D., associate professor
of Medicine and medical director of the AIDS Center at Strong Memorial
Hospital, and Susan Cohn, M.D., associate professor of Medicine at the
University of Rochester School of Medicine and Dentistry, also took part
in the study.
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- "These findings underscore the importance of maintaining
a healthy, Lactobacillus-dominant vaginal flora for HIV-positive women,"
said Hitti. "I hope that we can explore Lactobacillus replacement
in the future for women who do not have this bacteria, as a strategy to
decrease the amount of HIV in the vagina."
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- "The research opens up some doors," said Luque.
"Sexual activity is the most common mode of transmission of HIV. Perhaps
we can make it less likely to spread by somehow taking advantage of good
bacteria as a natural way to stop HIV and prevent transmission. These findings
are striking, though preliminary, and should be looked at further."
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- Luque and Cohn both care for patients at Strong's AIDS
clinic, which provides ongoing care for approximately 900 patients with
HIV. The center is part of a broader AIDS treatment and research effort
at the University of Rochester Medical Center. The University is the only
institution in the nation to be part, since inception, of two major national
AIDS research efforts - the search for a vaccine, and the testing of new
treatments. More than 3,000 Rochester-area residents have taken part in
treatment and vaccine studies at the University's HIV/AIDS Clinical Trials
Unit, funded by the National Institute of Allergy and Infectious Diseases.
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- Cohn stresses the importance of HIV-positive women participating
in clinical research. "These women made a large contribution to knowledge
about HIV and reproductive health by participating in this study. Advances
in the care of HIV-positive women really depend on the dedication of study
subjects."
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- <http://www.urmc.rochester.edu/>http://www.urmc.rochester.edu/
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