title: Heterogenic virulence in a diarrheagenic Escherichia coli: evidence for an EPEC expressing heat-labile toxin of ETEC.
abstract: We have encountered an Escherichia coli strain isolated from a child with acute diarrhea. This strain harbored eae and elt genes encoding for E. coli attaching and effacing property and heat-labile enterotoxin of EPEC and ETEC, respectively. Due to the presence of these distinct virulence factors, we named this uncommon strain as EPEC/ETEC hybrid. The elt gene was identified in a conjugally transferable plasmid of the EPEC/ETEC hybrid. In addition, several virulence genes in the locus of enterocyte effacement have been identified, which confirms that the EPEC/ETEC has an EPEC genetic background. The hybrid nature of this strain was further confirmed by using tissue culture assays. In the multi locus sequence typing (MLST) analysis, the EPEC/ETEC belonged to the sequence type ST328 and was belonging to ST278 Cplx. Sequence analysis of the plasmid DNA revealed presence of six large contigs with several insertion sequences. A phage integrase gene and the prophages of gp48 and gp49 have been found in the upstream of eltAB. In the downstream of elt, an urovirulence loci adhesion encoding (pap) cluster containing papG, and papC were also identified. Similar to other reports, we have identified a heterogenic virulence in a diarrheagenic E. coli but with different combination of genes.
authors.affiliation: Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India.
authors.forename: Sanjucta
authors.initials: S
authors.lastname: Dutta
authors.affiliation: Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India.
authors.forename: Gururaja P
authors.initials: GP
authors.lastname: Pazhani
authors.affiliation: Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia.
authors.forename: James P
authors.initials: JP
authors.lastname: Nataro
authors.affiliation: Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India. Electronic address: tramu@vsnl.net.
authors.forename: Thandavarayan
authors.initials: T
authors.lastname: Ramamurthy
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics*; D001427:Bacterial Toxins / Q000235:genetics*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D003967:Diarrhea / Q000382:microbiology*; D054308:Enteropathogenic Escherichia coli / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D054307:Enterotoxigenic Escherichia coli / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D004768:Enterotoxins / Q000235:genetics*; D004927:Escherichia coli Infections / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics*; D006801:Humans; D007223:Infant; D008297:Male; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D010957:Plasmids; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D018829:Adhesins, Bacterial; D001427:Bacterial Toxins; D004269:DNA, Bacterial; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D037521:Virulence Factors; C073819:eaeA protein, E coli; C027538:heat-labile enterotoxin, E coli
keywords: Diarrhea; E. coli; EPEC; ETEC; Hybrid strain; eae; elt; pap