Microbiological investigations on cryopreserved human semen

Area of Science:

• Microbiology
• Reproductive Biology
• Cryobiology

Background:

• Human semen can harbor microbial contaminants.
• Understanding the impact of cryopreservation on semen microbiota is crucial for assisted reproductive technologies.

Purpose of the Study:

• To investigate primary and secondary mycological and bacteriological contamination in human ejaculates.
• To assess the effect of cryopreservation and antibiotics on microbial contamination in semen.

Main Methods:

• Analysis of 565 human ejaculates for primary contamination.
• Investigation of secondary contamination in 55 ejaculates post-cryopreservation.
• Bacteriological examination of 25 ejaculates before and after cryopreservation, with and without antibiotics.
• Inoculation of semen with specific yeasts, Escherichia coli, and Staphylococcus aureus.

Main Results:

• Primary mycological contamination detected in 9.8% of samples (1.9% Candida albicans).
• Cryopreservation reduced fungal concentration by over 90%.
• Bacterial contamination was low; non-pathogenic bacteria were largely unaffected by cryopreservation and antibiotics.
• Antibiotics in cryoprotective media did not prevent contamination or affect inoculated test bacteria.

Conclusions:

• Cryopreservation is effective in reducing fungal load in human semen.
• Current cryopreservation methods show limited efficacy against bacterial contamination, including non-pathogenic species.
• Further research is needed to develop effective strategies for eliminating bacterial contamination during semen cryopreservation.