A large outbreak of hemolytic uremic syndrome caused by an unusual sorbitol-fermenting strain of Escherichia coli O157 : H-

Escherichia coil O157:H7 does not ferment sorbitol, a factor used to differ entiate it from other E. coli. From December 1995 to March 1996, 28 childre n with hemolytic uremic syndrome in Bavaria, Germany, were identified; many had a sorbitol-fermenting (sf) E. coli O157:H- cultured. A case-control st udy showed a dose-response relationship between sausage consumption and ill ness. A second case-control study showed a relationship between mortadella and teewurst consumption and illness, particularly during December (mortade lla odds ratio [OR], 10.5, P = .004; teewurst OR, 6.2, P = .02), Twelve sf O157:H- were characterized to determine clonality and virulence traits. The strains possessed the Stx(2), eae, and EHEC-hlyA genes but were nonhemolyt ic on blood agar plates. The O157:H- isolates belonged to phage type 88 and had identical pulsed-field gel electrophoresis patterns. This outbreak was caused by sf E. coli O157:H-, which is not detectable by culture on sorbit ol MacConkey's agar. Consumption of two sausages, including a raw beef-cont aining sausage, was statistically related to illness.