A COMPARISON OF HUMAN AND BOVINE ESCHERICHIA-COLI O157-H7 ISOLATES BYTOXIN GENOTYPE, PLASMID PROFILE, AND BACTERIOPHAGE LAMBDA-RESTRICTIONFRAGMENT LENGTH POLYMORPHISM PROFILE

Foods of bovine origin have been linked to human disease outbreaks cau sed by Escherichia coli O157:H7 and may be linked to the more common s poradic cases as well. In this study, E. coli O157:H7 from the bovine reservoir (22 isolates: 12 from dairy and 10 from beef breed cows) and from human patients (50 isolates from sporadic human infections) were compared using Shiga-like toxin genotypes, plasmid profiles, and DNA restriction fragment length polymorphisms identified with a bacterioph age lambda probe (lambda-RFLP). Twenty-three lambda-RFLP profiles, 4 S higa-like toxin genotypes, and 8 plasmid profiles were identified amon g the isolates tested. Together the typing methods distinguished 43 st rains, of which 3 were isolated from both humans (5 isolates) and catt le (6 isolates; 5 from dairy herds). These data demonstrate the value of lambda-RFLP as a means of strain identification for E. coli O157:H7 .