Study published in PLoS ONE, 5(1): e8422. doi:10.1371/journal.pone.0008422. The authors determined that there is a difference in the microbiota between circumcised and intact men.  Circumcision was associated with a significant change in the overall microbiota  and with a significant decrease in putative anaerobic bacterial families.

The introduction includes a good discussion on the effect of Langerhans cells in HIV transmission. The authors describe experiments that support the link between genital microbial communities and HIV susceptibility and the importance of genital mucosal inflammation in HIV sexual transmission.