Effect of Washing, Antibiotics and Trypsin Treatment of Bovine Embryos on the Removal of Adhering K99⁺ Escherichia coli

Abstract

Bovine embryos with the intact zona pellucida were exposed in vitro to K99⁺ Escherichia coli (K99 E. coli). The recommended procedures for washing and treating embryos were then evaluated for their effectiveness in removing or killing the adherent bacteria. After 10-step washing, bacteria were recovered not only from the embryos exposed to E. coli suspensions but also from those treated with trypsin during washing. On the other hand, no bacteria were recovered from any embryos treated with antibiotics (gentamicin; 50μg/ml) in culture medium before washing, indicating that the recommended washing procedures with appropriate antibiotics assure that zona pellucida-intact bovine embryos are free from E. coli.