Effects of Escherichia coli and Staphylococcus aureus Inoculation on Human Sperm Parameters

Introduction: Infertility is one of the global health problems. The bacterial infection of semen and genital tract is one of the causes of the decline in male fertility. Defects in spermatogenesis and sperm function may be due to cellular reactions against microbial agents, as well as the direct effect of bacteria on germ cells. The recognition of the interaction between bacteria and reproductive system plays an important role in treating infertile men. The aim of this study was to examine the in vitro direct effect of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) on the motility, morphology, and viability of human spermatozoa, and compare the effect of these bacteria on the quality of sperm. Materials and Methods: The study was carried out on swim-up-separated spermatozoa from 33 men referred to the Nikan Infertility Treatment Center in Tehran, Iran, in 2018. After the removal of seminal plasma, the sperm suspension of each sample was divided into three parts. The first and second parts (i.e., experimental groups) were coincubated with E. coliand S. aureus, respectively, for 90 min at 37°C, and the third part (i.e., control group) was incubated at the same condition but without bacteria. Sperm parameters were assessed after the incubation. Statistical analysis was done to find the significant differences between the experimental groups and control group. Results: The results showed that E. coliand S. aureus infection caused a significant decline in the morphology, motility, and viability of two experimental groups in comparison to that reported for the control group (P<0.05). Conclusion: The results of this study revealed that the contact of bacteria with ejaculated spermatozoa can decrease sperm motility, morphology, and viability, with potential consequences for male fertility.