ISOLATION AND CHARACTERIZATION OF A BETA-D-GLUCURONIDASE-PRODUCING STRAIN OF ESCHERICHIA-COLI SEROTYPE O157-H7 IN THE UNITED-STATES

A phenotypic variant of Escherichia coli serotype 0157:H7 (G5101) was isolated from a patient with bloody diarrhea. Strain G5101 does not fe rment sorbitol but is beta-D-glucuronidase and urease positive. Seroty ping and colony hybridization using a serotype-specific DNA probe conf irmed that the isolate was 0157:H7. G5101 produces Shiga-like toxins I and II and contains an eae gene that is highly conserved in the 0157: H7 serotype. This strain would have been missed by laboratories that s creen for the sorbitol-negative, beta-D-glucuronidase-negative phenoty pe in isolating E. coli 0157:H7 from clinical and food specimens.