Effect of Escherichia coli and its soluble factors on mitochondrial membrane potential, phosphatidylserine translocation, viability, and motility of human spermatozoa

Objective: To evaluate the effect of Escherichia coli and its soluble factors on the viability and function of human spermatozoa. Design: In this prospective study, after removal of seminal plasma, the sperm suspension was incubated in vitro with E. coli or with supernatant from E. coli culture. Setting: Andrology laboratory in a medical research institution. Patient(s): Semen was obtained from normozoospermic men. Intervention(s): Semen samples were evaluated to determine the effect of E. coli and its soluble factors on sperm viability, motility, mitochondrial membrane potential (Delta Psi m), phosphatidylserine translocation, and reactive oxygen species generation. Main Outcome Measure(s): To verify the effect of E. coli and its soluble factors on sperm function. Result(s): After incubation with E. coli, the percentage of sperm with intact Delta Psi m decreased significantly, as did sperm viability and motility. Reactive oxygen species levels and phosphatidylserine translocation did not increase significantly. After sperm incubation with E. coli supernatant, a significant reduction in Delta Psi m, viability, and motility were also observed. Conclusion(s): Escherichia coli and its soluble factors affect sperm function, suggesting that the harmful effects of bacterial infection do not require that the spermatozoon come into direct contact with bacteria. (Fertil Steril (R) 2010;94:619-23. (C) 2010 by American Society for Reproductive Medicine.)