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Infect Immun. 2014 Nov;82(11):4631-42. doi: 10.1128/IAI.01701-14. Epub 2014 Aug 25.

Characterization of urinary tract infection-associated Shiga toxin-producing Escherichia coli.

Author information

1
Institute of Hygiene, University of Münster, Münster, Germany.
2
Institute of Hygiene, University of Münster, Münster, Germany Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany.
3
Institute of Hygiene, University of Münster, Münster, Germany Interdisciplinary Center for Clinical Research (IZKF), University of Münster, Münster, Germany.
4
Institute of Hygiene, University of Münster, Münster, Germany Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany dobrindt@uni-muenster.de.

Abstract

Enterohemorrhagic Escherichia coli (EHEC), a subgroup of Shiga toxin (Stx)-producing E. coli (STEC), is a leading cause of diarrhea and hemolytic-uremic syndrome (HUS) in humans. However, urinary tract infections (UTIs) caused by this microorganism but not associated with diarrhea have occasionally been reported. We geno- and phenotypically characterized three EHEC isolates obtained from the urine of hospitalized patients suffering from UTIs. These isolates carried typical EHEC virulence markers and belonged to HUS-associated E. coli (HUSEC) clones, but they lacked virulence markers typical of uropathogenic E. coli. One isolate exhibited a localized adherence (LA)-like pattern on T24 urinary bladder epithelial cells. Since the glycosphingolipids (GSLs) globotriaosylceramide (Gb3Cer) and globotetraosylceramide (Gb4Cer) are well-known receptors for Stx but also for P fimbriae, a major virulence factor of extraintestinal pathogenic E. coli (ExPEC), the expression of Gb3Cer and Gb4Cer by T24 cells and in murine urinary bladder tissue was examined by thin-layer chromatography and mass spectrometry. We provide data indicating that Stxs released by the EHEC isolates bind to Gb3Cer and Gb4Cer isolated from T24 cells, which were susceptible to Stx. All three EHEC isolates expressed stx genes upon growth in urine. Two strains were able to cause UTI in a murine infection model and could not be outcompeted in urine in vitro by typical uropathogenic E. coli isolates. Our results indicate that despite the lack of ExPEC virulence markers, EHEC variants may exhibit in certain suitable hosts, e.g., in hospital patients, a uropathogenic potential. The contribution of EHEC virulence factors to uropathogenesis remains to be further investigated.

PMID:
25156739
PMCID:
PMC4249321
DOI:
10.1128/IAI.01701-14
[Indexed for MEDLINE]
Free PMC Article

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