ABSTRACT
Male circumcision reduces
female-to-male HIV transmission. Hypothesized mechanisms for this
protective effect include decreased
HIV target cell recruitment and activation due
to changes in the penis microbiome. We compared the coronal sulcus
microbiota
of men from a group of uncircumcised controls (n = 77) and from a circumcised intervention group (n
= 79) at enrollment and year 1 follow-up in a randomized circumcision
trial in Rakai, Uganda. We characterized microbiota
using16S rRNA gene-based quantitative PCR (qPCR)
and pyrosequencing, log response ratio (LRR), Bayesian classification,
nonmetric
multidimensional scaling (nMDS), and
permutational multivariate analysis of variance (PerMANOVA). At
baseline, men in both
study arms had comparable coronal sulcus
microbiota; however, by year 1, circumcision decreased the total
bacterial load and
reduced microbiota biodiversity. Specifically,
the prevalence and absolute abundance of 12 anaerobic bacterial taxa
decreased
significantly in the circumcised men. While
aerobic bacterial taxa also increased postcircumcision, these gains were
minor.
The reduction in anaerobes may partly account
for the effects of circumcision on reduced HIV acquisition.
IMPORTANCE The
bacterial changes identified in this study may play an important role in
the HIV risk reduction conferred by male circumcision.
Decreasing the load of specific anaerobes could
reduce HIV target cell recruitment to the foreskin. Understanding the
mechanisms
that underlie the benefits of male circumcision
could help to identify new intervention strategies for decreasing HIV
transmission,
applicable to populations with high HIV
prevalence where male circumcision is culturally less acceptable.
0 Comments:
Post a Comment