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Keywords:

  • enterococci;
  • sperm;
  • sperm membrane;
  • hypoosmotic swelling test;
  • ultrastructure

Abstract

Aim: To study the influence of enterococci on human sperm membrane in vitro. Methods: Ejaculated human sperm were artificially infected with β-hemolytic or non-β-hemolytic enterococci at the bacteria: sperm ratio of 50:1 at 37°C. Sperm membrane integrity was examined after incubation for 1, 3 and 5 h by hypoosmotic swelling (HOS) test and electron microscopy. Results: Sperm infected with β-hemolytic enterococci had lower HOS scores compared with non-β-hemolytic strains or uninfected control (P < 0.01). The HOS test scores of sperm infected with β-hemolytic enterococci increased in the presence of phosphatidylcholine, an inhibitor of hemolysin. Non-β-hemolytic strains showed no significant difference in swelling rate, compared with the control group (P > 0.05). It was shown by electron microscopy that β-hemolytic enterococci caused significant rupture of human sperm membrane. Conclusion: β-hemolytic enterococci caused human sperm membrane injury, and might be mediated by the hemolysin of enterococci.

Edited by Prof. Hector Chemes