title: Microbiota of the seminal fluid from healthy and infertile men.
abstract: OBJECTIVE
  To explore potential causes of male infertility by determining the composition and structure of commensal bacterial communities in seminal fluids.
  
  
  METHODS
  Microscopy of Gram-stained semen samples and classification of 16S rRNA gene sequences to determine the species composition of semen bacterial communities.
  
  
  METHODS
  Clinical andrology laboratory and academic research laboratories.
  
  
  METHODS
  Nineteen sperm donors and 58 infertility patients.
  
  
  METHODS
  None.
  
  
  METHODS
  Classification of 16S rRNA gene sequences, clustering of seminal microbial communities, and multiple statistical tests.
  
  
  RESULTS
  High numbers of diverse kinds of bacteria were present in most samples of both sperm donors and infertility patients. The bacterial communities varied widely among subjects, but they could be clustered into six groups based on similarities in composition and the rank abundances of taxa. Overall, there were no significant differences between sperm donors and infertility patients. However, multiple statistical tests showed a significant negative association between sperm quality and the presence of Anaerococcus. The results also indicated that many of the bacterial taxa identified in semen also occur in the vaginal communities of some women, especially those with bacterial vaginosis, which suggests that heterosexual sex partners may share bacteria.
  
  
  CONCLUSIONS
  Diverse kinds of bacteria were present in the human semen, but there were no significant differences between sperm donors and infertility patients. The presence of Anaerococcus might be a biomarker for low sperm quality.
authors.affiliation: Department of Histology and Embryology, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China; Shanghai Key Laboratory of Reproductive Medicine, Shanghai, People's Republic of China.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Hou
authors.forename: Xia
authors.initials: X
authors.lastname: Zhou
authors.forename: Xue
authors.initials: X
authors.lastname: Zhong
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Settles
authors.forename: Jessica
authors.initials: J
authors.lastname: Herring
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Zaid
authors.initials: Z
authors.lastname: Abdo
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Forney
authors.forename: Chen
authors.initials: C
authors.lastname: Xu
mesh_terms: D000328:Adult; D001419:Bacteria / Q000145:classification / Q000235:genetics*; D016022:Case-Control Studies; D016000:Cluster Analysis; D003430:Cross-Sectional Studies; D004269:DNA, Bacterial / Q000302:isolation & purification; D005819:Genetic Markers; D006801:Humans; D007248:Infertility, Male / Q000382:microbiology*; D008297:Male; D016017:Odds Ratio; D016016:Proportional Hazards Models; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D021521:Ribotyping; D012307:Risk Factors; D012661:Semen / Q000382:microbiology*; D055101:Semen Analysis / Q000379:methods; D013076:Sperm Count; D013081:Sperm Motility; D013194:Staining and Labeling; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial; D005819:Genetic Markers; D012336:RNA, Ribosomal, 16S
keywords: Semen; bacterial communities; fertility; microbiome; reproduction