Enterohemorrhagic Escherichia coli as Causes of Hemolytic Uremic Syndrome in the Czech Republic

Background: Enterohemorrhagic Escherichia coli (EHEC) cause diarrhea-associated hemolytic uremic syndrome (D+ HUS) worldwide, but no systematic study of EHEC as the causative agents of HUS was performed in the Czech Republic. We analyzed stools of all patients with D+ HUS in the Czech Republic between 1998 and 2012 for evidence of EHEC infection. We determined virulence profiles, phenotypes, antimicrobial susceptibilities and phylogeny of the EHEC isolates. Methodology/Principal Findings: Virulence loci were identified using PCR, phenotypes and antimicrobial susceptibilities were determined using standard procedures, and phylogeny was assessed using multilocus sequence typing. During the 15-year period, EHEC were isolated from stools of 39 (69.4%) of 56 patients. The strains belonged to serotypes [fliC types] O157:H7/NM[fliC(H7)] (50% of which were sorbitol-fermenting; SF), O26: H11/NM[fliC(H11)], O55:NM[fliC(H7)], O111:NM[fliC(H8)], O145:H28[fliC(H28)], O172: NM[fliC(H25)], and Orough: NM[fliC(H25)]. O26: H11/NM[fliC(H11)] was the most common serotype associated with HUS (41% isolates). Five stx genotypes were identified, the most frequent being stx(2a) (71.1% isolates). Most strains contained EHEC-hlyA encoding EHEC hemolysin, and a subset (all SF O157: NM and one O157: H7) harbored cdtV encoding cytolethal distending toxin. espP alpha encoding serine protease EspP alpha was found in EHEC O157: H7, O26: H11/NM, and O145: H28, whereas O172: NM and Orough: NM strains contained espP gamma. All isolates contained eae encoding adhesin intimin, which belonged to subtypes beta (O26), gamma (O55, O145, O157), gamma 2/0 (O111), and epsilon (O172, Orough). Loci encoding other adhesins (efa1, lpfA(O26), lpfA(O157OI-141), lpfA(O157OI-154), iha) were usually associated with particular serotypes. Phylogenetic analysis demonstrated nine sequence types (STs) which correlated with serotypes. Of these, two STs (ST660 and ST1595) were not found in HUS-associated EHEC before. Conclusions/Significance: EHEC strains, including O157: H7 and non-O157: H7, are frequent causes of D+ HUS in the Czech Republic. Identification of unusual EHEC serotypes/STs causing HUS calls for establishment of an European collection of HUS-associated EHEC, enabling to study properties and evolution of these important pathogens.