Ureaplasma urealyticum in male infertility in Jilin Province, North-east China, and its relationship with sperm morphology.

This study investigated the effects of Ureaplasma urealyticum infection and raised seminal leucocyte levels on sperm morphology in 967 infertile males and 201 fertile healthy volunteers. U. urealyticum infection led to a significant decrease in the percentage of morphologically normal sperm in infertile males. There was a clear correlation between U. urealyticum infection, raised seminal leucocytes and abnormal sperm morphology. The percentage of morphologically normal sperm was significantly lower in U. urealyticum-positive than U. urealyticum-negative infertile males or fertile controls. The percentage of morphologically normal sperm was lowest in U. urealyticum-positive males with raised seminal leucocytes. Previous studies have found raised seminal leucocyte levels to be associated with reactive oxygen species. The authors suggest that oxidative stress contributes to the effects of U. urealyticum on sperm morphology. In conclusion, U. urealyticum infection can negatively affect sperm morphology and this study provided two possible mechanistic explanations.