Diverse Genetic Markers Concordantly Identify Bovine Origin Escherichia coli O157 Genotypes Underrepresented in Human Disease

Genetic markers previously reported to occur at significantly different frequencies in isolates of Escherichia coli O157:H7 obtained from cattle and from clinically affected humans concordantly delineate at least five genetic groups. Isolates in three of these groups consistently carry one or more markers rarely found among clinical isolates.