title: Male circumcision significantly reduces prevalence and load of genital anaerobic bacteria.
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.
  
  
  OBJECTIVE
  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.
authors.affiliation: Division of Pathogen Genomics, Translational Genomics Research Institute, Flagstaff, Arizona, USA.
authors.forename: Cindy M
authors.initials: CM
authors.lastname: Liu
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Hungate
authors.forename: Aaron A R
authors.initials: AA
authors.lastname: Tobian
authors.forename: David
authors.initials: D
authors.lastname: Serwadda
authors.forename: Jacques
authors.initials: J
authors.lastname: Ravel
authors.forename: Richard
authors.initials: R
authors.lastname: Lester
authors.forename: Godfrey
authors.initials: G
authors.lastname: Kigozi
authors.forename: Maliha
authors.initials: M
authors.lastname: Aziz
authors.forename: Ronald M
authors.initials: RM
authors.lastname: Galiwango
authors.forename: Fred
authors.initials: F
authors.lastname: Nalugoda
authors.forename: Tania L
authors.initials: TL
authors.lastname: Contente-Cuomo
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Wawer
authors.forename: Paul
authors.initials: P
authors.lastname: Keim
authors.forename: Ronald H
authors.initials: RH
authors.lastname: Gray
authors.forename: Lance B
authors.initials: LB
authors.lastname: Price
mesh_terms: D000293:Adolescent; D000328:Adult; D001421:Bacteria, Anaerobic / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D058491:Bacterial Load; D044822:Biodiversity; D002944:Circumcision, Male; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010413:Penis / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D014454:Uganda; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S