Microbial flora in semen during in vitro fertilization.

Semen samples from 183 consecutive unselected men participating in an in vitro fertilization program were retrospectively studied to determine the bacterial and fungal contamination rate before and after antibiotic treatment. To ascertain the influence of semen preparation (wash and swim-up method) on the incidence of microorganisms, semen from 102 male patients was studied before and after swimup. Antimicrobial treatment by prescription of antibiotics decreased the incidence of pathogens by 16.3% (P less than 0.0001). Semen processing was more effective by ridding 57.4% of semen samples of microbial contaminants (P less than 0.0001). When infection of culture media was observed during routine microscopy, all infected oocytes were degenerated, without evidence of fertilization or pronuclei.