Processing of semen in an antibiotic-rich culture medium to minimize microbial presence during in vitro fertilization.

Objective: To identify and determine the prevalence of microorganisms in preprocessed and postprocessed semen in an IVF-ET program.

Design: Prospective study.

Setting: University Teaching Hospital.

Patient(s): Seventy-four men undergoing preprogram evaluation, each producing two semen samples.

Intervention(s): Semen processing with a wash and swim-up technique in a penicillin- and streptomycin-rich medium.

Main Outcome Measure(s): The identity and prevalence of seminal microorganisms before and after processing.

Result(s): Sixty-three percent of individual unprocessed semen samples grew microorganisms, the majority of which were nonpathogenic. Thirty-three men (44.6%) had microbes identified in repeat samples, four had identical organisms each time. Twenty (27%) had positive cultures in one sample, negative in the other. Twenty-one (28.4%) had consistently sterile semen. After seminal processing, the recovery rate for microbes was 5%. Microbial presence after processing did not correlate with either the sperm swim-up concentration or the initial microbial concentration.

Conclusion(s): Bacteriospermia is common. The microorganisms found rarely are replicated and most likely represent contamination. Wash and swim-up semen preparation in an antibiotic rich culture medium effectively eliminates 95% of organisms.