POLYMERASE CHAIN REACTION-BASED DETECTION OF BACTERIA IN SEMEN

Objective: To determine if the presently used bacterial detection tech niques provide accurate and complete profiles of microorganisms found in human semen. Design: Routine bacterial cultures and molecular biolo gy techniques using polymerase chain reaction (PCR), with a universal eubacterial primer, cloning, then sequence analysis were used to detec t bacteria (culturable or nonculturable) in the semen. Setting: Univer sity and hospital-based research laboratory. Patients: Thirty infertil e men and nine semen donors, all with no symptoms of a urinary tract i nfection, donated semen for the study. Interventions: None. Main Outco me Measures: Detection of bacteria using routine cultures and molecula r biology techniques. Results: Using PCR, we found >10(4) bacteria/mL in the semen of 66% of the infertile asymptomatic men and 66% of the s emen donors. This contrasts with our routine culture results which det ected ''significant'' bacteriospermia in only 27% of the infertile men and in none of the preselected semen donors. From four of these semen specimens, DNA sequence analysis identified an average of nine differ ent bacterial species per specimen, with close to 90% of the species b eing anaerobes. Conclusions: These data indicate that the present micr obiologic detection methods underestimate the incidence of significant bacteriospermia, particularly anaerobic bacteria. The molecular biolo gic methods should help researchers confirm or refute the role of infe ction in male infertility.