Virulence Factors and Phenotypical Traits of Verotoxin-Producing Escherichia coli Strains Isolated from Asymptomatic Human Carriers

Fourteen verotoxin-producing Escherichia coli strains isolated from stool samples of 14 different asymptomatic human carriers were further characterized. A variety of serotypes was found, but none of the strains belonged to serogroup O157. Only one isolate carried most of the virulence genes that are associated with increased pathogenicity.