Sorbitol-negative phenotype among enterohemorrhagic Escherichia coli strains of different serotypes and from different sources.

Enterohemorrhagic Escherichia coli (EHEC) strains detected with DNA probes (for virulence plasmid and Shiga-like toxins) from subjects with hemolytic-uremic syndrome (n = 19) or diarrhea (n = 41) or asymptomatic carriers (n = 29) were examined for sorbitol fermentability, as were enterotoxigenic (n = 40), enteropathogenic (n = 40), and enteroinvasive (n = 40) E. coli and urinary tract infection (n = 40) strains and normal flora E. coli strains (n = 40). Sorbitol negativity was common only in EHEC, particularly among strains from severe clinical infections. All 19 EHEC strains from patients with hemolytic-uremic syndrome, irrespective of O:H serotype or Shiga-like toxin genotype, were sorbitol negative.