Are seminal fluid microorganisms of significance or merely contaminants?

OBJECTIVE

To determine the contribution of urethral and skin flora to seminal fluid cultures and the relation between bacteriospermia and seminal leukocytes.

DESIGN

Prospective study.

SETTING

IVF-ET unit at a university teaching hospital.

PATIENT(S): Sixty men starting an IVF-ET program.

INTERVENTION(S): Culture of sequential first-catch urine, midstream urine, and semen samples with evaluation of seminal leukocytes.

MAIN OUTCOME MEASURE(S): A comparison of microbes from first-catch urine, midstream urine, and semen samples and the correlations of seminal microbes, elevated leukocyte concentrations, and pregnancy.

RESULT(S): Microorganisms were detected in 37% of first-catch urine samples, 27% of midstream urine samples, and 51% of semen samples. Most microorganisms were gram-positive microbes and were common to both urine and semen samples. Mean and median leukocyte concentrations were 0.98 x 10(6)/mL and 0.10 x 10(6)/mL, respectively. There was no correlation between seminal microbes and raised leukocytes or between leukocytospermia and/or bacteriospermia and pregnancy.

CONCLUSION(S): Microorganisms are commonly found in insignificant quantities in the semen of asymptomatic men. The frequent isolation of gram-positive microbes common to both urine and semen and the absence of a correlation with raised leukocyte concentrations suggest that bacteriospermia most commonly represents contamination.