title: Detection and identification of bacterial DNA in semen.
abstract: OBJECTIVE
  To detect and identify bacteria in semen by sequencing polymerase chain reaction (PCR)-amplified ribosomal RNA gene regions (rDNAs).
  
  
  METHODS
  Bacterial rDNAs were detected by PCR amplification of semen DNA. Conditions were adjusted to detect only abundant organisms, no fewer than 20,000 bacteria/mL of semen.
  
  
  METHODS
  Clinical andrology laboratory and academic research laboratories.
  
  
  METHODS
  Men undergoing fertility evaluation (n = 29) or vasectomy (n = 5).
  
  
  METHODS
  None. MAIN OUTCOME MEAURE(S): Frequency of bacterial rDNA-positive specimens, relationship of rDNAs to bacteria in GenBank, and correlation with semen cells.
  
  
  RESULTS
  Twenty-five (56%) of the specimens from 22 (65%) of the men were positive. A total of 141 bacterial rDNA sequences were compared with GenBank data for identification. The largest group matched gram-positive anaerobic cocci (Peptoniphilis, Anaerococcus, Finegoldia, Peptostreptococcus spp.) in 13 specimens, followed by Corynebacterium spp. in 10 specimens, Staphylococcus, Lactobacillus, and Streptococcus spp. in 7 specimens each, Pseudomonas spp. in 4 specimens, and Haemophilus and Acinetobacter spp. in 2 specimens each. The rDNA-positive specimens averaged 59 +/- 13 million sperm/mL, 46 +/- 5% of which were motile, not statistically different from the rDNA-negative specimens (77 +/- 16 million/mL, 47 +/- 5% motile). Normal sperm forms were lower in the rDNA-positive (10 +/- 1.1%) than in the rDNA-negative specimens (22 +/- 2%), and lymphocytes/monocytes were fivefold lower in the rDNA-positive specimens (0.4 +/- 0.2 million/mL) than in the negative specimens (1.9 +/- 0.7 million/mL).
  
  
  CONCLUSIONS
  Abundant bacteria in semen are not commensal, arise from infection in the male genitourinary tract, may influence fertility, and may reflect an inadequate cellular immune response.
authors.affiliation: Bedford Research Foundation Laboratories, Somerville, Massachusetts, USA. info@bedfordresearch.org
authors.forename: Ann A
authors.initials: AA
authors.lastname: Kiessling
authors.forename: Bryan M
authors.initials: BM
authors.lastname: Desmarais
authors.forename: Hui-Zhong
authors.initials: HZ
authors.lastname: Yin
authors.forename: Joseph
authors.initials: J
authors.lastname: Loverde
authors.forename: Robert C
authors.initials: RC
authors.lastname: Eyre
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001419:Bacteria / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D004269:DNA, Bacterial / Q000302:isolation & purification*; D030541:Databases, Genetic; D020459:Genes, rRNA; D006801:Humans; D007248:Infertility, Male / Q000188:drug therapy / Q000382:microbiology*; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D021521:Ribotyping; D012661:Semen / Q000382:microbiology*; D013076:Sperm Count; D013081:Sperm Motility
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial