- Specific bacteria
present in the vagina may play a role in sexual transmission of HIV, finds
a study from Ragon Institute.
- A diverse group
of vaginal bacteria increases vaginal inflammation and four-fold risk of
- Altering the
vaginal microbiome could aid in lowering vaginal inflammation and risk of
is one of the most
dreaded diseases and there are ongoing research projects that are aimed at
identifying possible mechanisms involved in the spread of the disease. A new
study by a research team from Ragon Institute has identified that a specific
bacteria that are found in the vagina play a role in the sexual transmission of
The role of these bacteria in HIV transmission has, for so long,
study was conducted on South African women who were young, healthy and working.
The findings of the study showed that women with a large amount of a
particular bacterial species in their vagina had a four-fold increase in the
risk of acquiring HIV when compared with women who did not have healthy vaginal
‘Specific vaginal bacteria play a role in HIV transmission as they provide a foothold for growth.’
study that appeared in the journal Immunity
and it found no correlation between viruses present in the vaginal tract and
risk of HIV infection.
micro-organisms that are normally found in humans are found to influence human
development, nutrition, immunity and physiology. A mutualistic relationship
exists between this microbiota and their human host, where both humans and the
microbiota benefit. There are a few, however, which are opportunistic pathogens
and lead to the development of serious illnesses.
High Risk Bacteria
the population of women who were studied, it was found that
bacteria was found among certain women
- Such women with high
risk bacterial population had a large number of CD4+T cells. These T
cells were the target for HIV
- Introduction of
pro-inflammatory species of bacteria intra-vaginally increased the number of mucosal CD4+T cells in mouse
findings suggest that certain bacteria found in the vagina could increase the
risk of HIV infection by providing a foothold for the virus to hold onto. This
brings to the importance of vaginal microbiota and its far reaching effects on
health and disease.
research team are now focusing on introducing probiotic bacteria which will
limit the growth and multiplication of the bacteria that have been implicated
in the spread of HIV infection. The probiotic microorganisms can be introduced
in women from vulnerable communities as a line of defense.
Gosmann who is a postdoctoral research fellow at the Ragon Institute said that
modern molecular approaches were used to characterize microbiome of the vagina
and to identify specific bacteria and the HIV infection among women who lived
in the sub-Saharan Africa. This is the region where HIV was found to be most
profound. The author further added that the findings from the study could be
applied directly to improve HIV
study included over 900 women between the ages of 18-23 from the KwaZulu
province of Durban in South Africa. These women took part in the Females Rising
Through Education, Support and Health(FRESH) study.
region is well known for its high HIV numbers. This region was visited by
volunteers, atleast twice a week and
people were enrolled in a poverty annihilation project, that provided job
opportunities, job skills training as well as HIV prevention education
research team which included senior author Dr. Douglas Kwon who is a physician
scientist at the Ragon Institute said that they were drawn to the region as it
has a high prevalence of HIV infection. Previous studies have shown that Chlamydia
could lead to inflammation in the vagina but the scientists believed that it
could not account for all the incidences of HIV. Based on a previous study
conducted by the same research team, it was suggested that there were certain
bacterial species that aided in the attachment, growth and differentiation of
on vaginal microbiome have previously stated that they were dominant in
Lactobacillus species. However, these studies have been largely associated with
white women. This current study showed that the vaginal microbiome contained
only 10% of Lactobacillus and that the presence of certain bacteria contributed
to the growth and development of HIV infection.
study found that
- Less than 10% of
South African women in the study had the 'healthy' community of vaginal
- 70% of the study
participants had diverse bacterial communities with low amounts of
studies showed that the diverse communities of bacteria were associated with
higher level of genital inflammation along with an increased risk of HIV
Differences in Vaginal
are two reasons for the differences in vaginal microbiome
- Genetic - Some people have hereditary factors that determine
the type of bacteria that grow in the vagina.
This includes hygiene, diet, contraception methods, sexual behavior and
Altering the Vaginal
research team have been trying to identify mechanisms by which the vaginal
microbiome could be altered to lower vaginal inflammation and to reduce the
risk of HIV infection. However, the challenge of increasing Lactobacillus in
the vagina is difficult as the use of antibiotics can lower the vaginal
microbial load but the composition of bacteria cannot be changed.
studies have suggested fecal transplant but they have also shown that the
vaginal microbiome returns to baseline after a period of time. Further research
needs to be carried out in this regard.
Kwon further added that more studies were needed to understand the significance
of microbial communities in the body and to discern their importance. There is
more to research on the microbiome than just their relevance in the gut.
- The vaginal microbiome: rethinking health and
diseases - (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3780402/)