Spermagglutination by bacteria: receptor-specific interactions

The influence of genital infection on infertility has yet to be elucidated. We examined receptor-ligand interactions between sperm and Escherichia coli from patients with prostatitis. Two E. coli surface adhesins (P-fimbriae, type 1 fimbriae) and their specific receptor saccharides (alpha-galp-1-4-beta-galp-O-methyl [gal-gal], mannose) were evaluated. Bacterial concentrations of 10(4) caused spermagglutination. P-fimbriae caused tail-tail spermagglutination that was inhibited by gal-gal. D-mannose concentrations are highest in the acrosomal region and type 1 fimbriae caused head-head agglutination that was inhibited by mannose. Strains with both fimbriae caused head-head and tail-tail agglutination that was inhibited by a mannose/gal-gal combination. E. coli agglutinated 40-75% of motile sperm. Seminal fluid provided 50-100% protection, with lower effectiveness against type 1 fimbriae. Understanding bacteria-spermatozoa interactions at the receptor-ligand level holds potential for treatment of infertility and development of spermagglutinating contraceptives.