The effect of presence of facultative bacteria species on semen and sperm quality of men seeking fertility care

IntroductionInfections of male urogenital tracts may contribute to male infertility. However, the effects of bacterial presence on sperm quality and fertility are controversial.ObjectivesWe investigated the occurrence of non-specific bacteria and quality/quantity of semen of infertile and fertile control groups in Nigeria.Subjects and methodsWe investigated 162 infertile and 54 fertile men. Spermiogram, culture, bacterial isolation and characterization were conducted.ResultsWe report 114/162(70.4%) occurrence of bacteria species, 49.4% of such were Gram positive and 21% Gram negative: Staphylococcus aureus (29.6%) and Escherichia coli (10.5%) had the highest occurrence for each group respectively. On semen quality/quantity, we report 14.2% azoospermia, 52.5% oligozoospermia and 33.3% of normozoospermia. The mean sperm concentrations were 10 × 7/ml and 41 × 10 6/ml for oligo and normozoospermia respectively. Majority (52%) of azoospermic group had no bacterial growth. S. aureus was the most implicated among the bacterial positive group. Within the ologozoospermic category, 28% had no bacterial growth, 28% had S. aureus and 11.8% E. coli. The normozoospermic patients had 18.5% no bacteria contamination, 33.3% had S. aureus, 13% had E. coli. From the analysis, the normozoospermic group with bacterial contamination had lower sperm concentrations compared with those without contamination. It was apparent that factors other than bacterial contamination may contribute more to oligozoospermia (compare: “no bacteria” group mean sperm concentration 8.97 × 106/ml, Gram positive bacteria contaminated group 17.74 × 106/ml and Gram negative bacteria contaminated group 13.66 × 106/ml). The mean progressive motility ratios were lower (15.6 [a]% + 18.3 [b]%) = 33.9%) against WHO standard (a + b = >50%) and control RPM (a) = 55.3%. Generally, the semen quality (vol., rapid progressive motility, sperm concentration and immotility) were significantly lower than the fertile group, P = 0.0005, <0.0001, <0001 and 0.0335, respectively.ConclusionsAlthough bacterial presence in semen reduced mean sperm concentration and viability, thereby contributed to oligozoospermia and by extension the chances of siring a child, however, factors other than bacterial presence may contribute more. Improved interpretative approaches of semen analyses are highlighted.