Prevalence, Virulence Profiles, and Clinical Significance of Shiga Toxin-Negative Variants of Enterohemorrhagic Escherichia coli O157 Infection in Humans

Abstract

Strains of stx-negative E. coli O157 isolated from stool samples of patients are either inherently stx-negative strains that cause mostly uncomplicated diarrhea, or strains that descended from enterohemorrhagic E. coli O157 by the loss of the stx gene during infection; the latter strains may still cause severe disease.