title: Phylogenetic and molecular analysis of food-borne shiga toxin-producing Escherichia coli.
abstract: Seventy-five food-associated Shiga toxin-producing Escherichia coli (STEC) strains were analyzed by molecular and phylogenetic methods to describe their pathogenic potential. The presence of the locus of proteolysis activity (LPA), the chromosomal pathogenicity island (PAI) PAI ICL3, and the autotransporter-encoding gene sabA was examined by PCR. Furthermore, the occupation of the chromosomal integration sites of the locus of enterocyte effacement (LEE), selC, pheU, and pheV, as well as the Stx phage integration sites yehV, yecE, wrbA, z2577, and ssrA, was analyzed. Moreover, the antibiotic resistance phenotypes of all STEC strains were determined. Multilocus sequence typing (MLST) was performed, and sequence types (STs) and sequence type complexes (STCs) were compared with those of 42 hemolytic-uremic syndrome (HUS)-associated enterohemorrhagic E. coli (HUSEC) strains. Besides 59 STs and 4 STCs, three larger clusters were defined in this strain collection. Clusters A and C consist mostly of highly pathogenic eae-positive HUSEC strains and some related food-borne STEC strains. A member of a new O26 HUS-associated clone and the 2011 outbreak strain E. coli O104:H4 were found in cluster A. Cluster B comprises only eae-negative food-borne STEC strains as well as mainly eae-negative HUSEC strains. Although food-borne strains of cluster B were not clearly associated with disease, serotypes of important pathogens, such as O91:H21 and O113:H21, were in this cluster and closely related to the food-borne strains. Clonal analysis demonstrated eight closely related genetic groups of food-borne STEC and HUSEC strains that shared the same ST and were similar in their virulence gene composition. These groups should be considered with respect to their potential for human infection.
authors: Department of Food Microbiology, Institute of Food Science and Biotechnology, University of Hohenheim, Stuttgart, Germany.
authors: Elisabeth
authors: E
authors: Hauser
authors: Alexander
authors: A
authors: Mellmann
authors: Torsten
authors: T
authors: Semmler
authors: Helen
authors: H
authors: Stoeber
authors: Lothar H
authors: LH
authors: Wieler
authors: Helge
authors: H
authors: Karch
authors: Nikole
authors: N
authors: Kuebler
authors: Angelika
authors: A
authors: Fruth
authors: Dag
authors: D
authors: Harmsen
authors: Thomas
authors: T
authors: Weniger
authors: Erhard
authors: E
authors: Tietze
authors: Herbert
authors: H
authors: Schmidt
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001435:Bacteriophages / Q000235:genetics; D001483:Base Sequence; D004269:DNA, Bacterial; D024881:Drug Resistance, Bacterial / Q000235:genetics; D004927:Escherichia coli Infections; D029968:Escherichia coli Proteins / Q000235:genetics; D005516:Food Microbiology; D044404:Genomic Islands; D006463:Hemolytic-Uremic Syndrome / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D021141:Nucleic Acid Amplification Techniques; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D022621:Shiga Toxin / Q000096:biosynthesis / Q000235:genetics*; D054323:Shiga-Toxigenic Escherichia coli / Q000145:classification / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D022621:Shiga Toxin