Genotypes and virulence characteristics of Shiga toxin-producing Escherichia coli 0104 strains from different origins and sources

Sixty-two Escherichia colt strains carrying the wzx(O104)-gene from different sources, origins and time periods were analyzed for their serotypes, virulence genes and compared for genomic similarity by pulsed-field gel-electrophoresis (PFGE). The 0104 antigen was present in 55 strains and the structurally and genetically related capsular antigen K9 in five strains. The presence of 49 genes associated with enteropathogenic E. coli (EPEC), enteroaggregative E. colt (EAEC) and enterohemorrhagic E. colt (EHEC) was investigated. Fifty-four strains of serotypes 0104:H2 (n = 1), 0104:H4 (n =37), 0104:H7 (n =5) and 0104:H21 (n = 11) produced Shiga-toxins (Stx). Among STEC 0104, a close association between serotype, virulence gene profile and genomic similarity was found. EAEC virulence genes were only present in STEC 0104:H4 strains. EHEC-0157 plasmid-encoded genes were only found in STEC 0104:H2, 0104:H7 and 0104:H21 strains. None of the 62 0104 or 1(9 strains carried an eae-gene involved in the attaching and effacing phenotype. The 38 0104:H4 strains formed a single PFGE-cluster (>83.7% similarity). Thirty-one of these strains were from the European 0104:H4 outbreak in 2011. The outbreak strains and older 0104:H4 strains from Germany (2001), Georgia and France (2009) clustered together at >86.2% similarity. 0104:H4 strains isolated between 2001 and 2009 differed for some plasmid-encoded virulence genes compared to the outbreak strains from 2011. STEC 0104:H21 and STEC 0104:H7 strains isolated in the U.S. and in Europe showed characteristic differences in their Stx-types, virulence gene and PFGE profiles indicating that these have evolved separately. E. colt 1(9 strains were not associated with virulence and were-heterogeneous for their serotypes and PFGE profiles. (C) 2013 Elsevier GmbH. All rights reserved.