title: Rectal microbiota among HIV-uninfected, untreated HIV, and treated HIV-infected in Nigeria.
abstract: Untreated advanced HIV infection alters the gut microbiota, but it is unclear whether antiretroviral therapy (ART) reverses these changes. We compared the composition of the rectal microbiota among three groups of men who have sex with men (MSM): HIV-uninfected, untreated HIV, and ART-treated HIV-infected.
  
  
  
  A cross-sectional study was conducted among 130 MSM (55 HIV-uninfected, 41 untreated HIV, and 34 ART-treated HIV) in Abuja, Nigeria.
  
  
  
  Bacterial 16S rRNA genes were amplified from rectal swabs, sequenced and clustered into Genera-level operational taxonomic units. Alpha diversity was quantified using the Shannon index and compared among groups using the Kruskal-Wallis test; associations with other scale variables were quantified using Spearman's rank correlation (Rs). The relative abundance of the top 15 taxa was compared according to HIV infection/treatment status using the Wilcoxon rank sum test.
  
  
  
  HIV-treated MSM had a decrease in a commensal phylum, Bacteroidetes (P < 0.01). Alpha diversity was positively correlated with viral loads (Rs = 0.32, P < 0.01). Statistically significant shifts in relative abundance of rectal microbiota for the HIV-treated group included a decrease in the most abundant bacteria, Prevotella (P = 0.02) and an increase in pathogenic bacteria, Peptoniphilus (P = 0.04), Finegoldia (P = 0.01), Anaerococcus (P = 0.03), and Campylobacter (P = 0.03) compared with the other groups.
  
  
  
  Untreated HIV infection does not significantly alter the rectal microbiota, whereas prior treatment is associated with a shift toward a more pathogenic pattern of microbiota. Treatment with an antibiotic, co-trimoxazole, in conjunction with ART may have contributed to this shift.
authors.affiliation: aInstitute of Human Virology, University of Maryland School of Medicine bUniversity of Maryland Greenebaum Comprehensive Cancer Center cDepartment of Epidemiology and Public Health dInstitute for Genome Sciences, University of Maryland School of Medicine, Baltimore eUS Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring fHenry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA gInstitute of Human Virology, Nigeria, Abuja, Nigeria hSchool of Public Health, University of Maryland, College Park iJohns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
authors.forename: Rebecca G
authors.initials: RG
authors.lastname: Nowak
authors.forename: Søren M
authors.initials: SM
authors.lastname: Bentzen
authors.forename: Jacques
authors.initials: J
authors.lastname: Ravel
authors.forename: Trevor A
authors.initials: TA
authors.lastname: Crowell
authors.forename: Wuese
authors.initials: W
authors.lastname: Dauda
authors.forename: Bing
authors.initials: B
authors.lastname: Ma
authors.forename: Hongjie
authors.initials: H
authors.lastname: Liu
authors.forename: William A
authors.initials: WA
authors.lastname: Blattner
authors.forename: Stefan D
authors.initials: SD
authors.lastname: Baral
authors.forename: Manhattan E
authors.initials: ME
authors.lastname: Charurat
mesh_terms: D044966:Anti-Retroviral Agents / Q000627:therapeutic use; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D044822:Biodiversity; D016000:Cluster Analysis; D003430:Cross-Sectional Studies; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D015658:HIV Infections / Q000188:drug therapy; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D064307:Microbiota; D009549:Nigeria; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012007:Rectum / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D000072339:Sexual and Gender Minorities
chemical_list: D044966:Anti-Retroviral Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S