A Simple Screening Method for Detection of Verocytotoxin-producing Escherichia coli

Abstract

Twenty-one strains of Escherichia coli were examined for hemolysis on Beutin agar, and 11 of 12 verocytotoxin (VT)-producing E. coli showed complete hemolysis, being divided into two types; widely diffuse and narrow focal. Since polymyxin B (PBE) extracts from agar culture of hemolytic E. coli, gave VT titers almost equal to those of shaking broth culture samples, hemolysis test of PBE samples using Beutin agar would be useful for simple screening of VT-producing E. coli.