Identification and distribution of the enterohemorrhagic Escherichia coli factor for adherence (efa1) gene in sorbitol-fermenting Escherichia coli O157: H-.

Abstract

Sorbitol-fermenting (SF) Shiga toxin (Stx)-producing Escherichia coli (STEC) O157:H- strains are emerging as causes of hemorrhagic colitis and the hemolytic-uremic syndrome in Europe. Using subtractive hybridization between SF STEC O157:H- strain 493/89 and STEC O157:H7 strain EDL933, three different fragments, of approximately 700 bp in length, were identified. Each demonstrated > 99% homology to genes encoding the enterohemorrhagic E. coli factor for adherence (efa1) and lymphostatin (lifA). Therefore, a cosmid library was constructed from SF STEC O157:H- strain 493/89, and one clone containing these fragments was sequenced. This sequencing demonstrated a 9669-bp open reading frame (ORF) that had 99.9% sequence homology to efa1 of STEC O111:H- strain E45035 and to lifA of an enteropathogenic E. coli O127:H6 strain E2348/69. In STEC O157:H7 strain EDL933, only small (ca. 3 kb) initial and terminal fragments of this ORF are present. PCR analysis with primers complementary to the efa1/lifA sequence of strain 493/89 indicated that the complete sequence is present in each of 10 SF STEC O157:H- isolates but in none of 10 STEC O157:H7 strains investigated. The presence of the complete efa1/lifA also in both tested E. coli O55:H7 strains supports the hypothesis that SF STEC O157:H- are phylogenetically closer to the proposed E. coli O55:H7 ancestor than STEC O157:H7. Our data demonstrate the presence of a potential virulence gene in SF STEC O157:H- that is only rudimentarily present in STEC O157:H7.

• Authors: Andreas Janka, Martina Bielaszewska, Ulrich Dobrindt, Helge Karch
• Journal: International journal of medical microbiology : IJMM (Int J Med Microbiol) Vol. 292 Issue 3-4 Pg. 207-14 (Sep 2002) ISSN: 1438-4221 [Print] Germany
• PMID: 12398211 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Bacterial Proteins
• Bacterial Toxins
• DNA, Bacterial
• Efa1 protein, E coli
• Escherichia coli Proteins
• Shiga Toxins
• lymphostatin protein, E coli
• Sorbitol

Topics

• Bacterial Proteins (genetics, isolation & purification, metabolism)
• Bacterial Toxins (genetics, isolation & purification, metabolism)
• Base Sequence
• DNA, Bacterial (chemistry, genetics)
• Escherichia coli O157 (genetics, metabolism)
• Escherichia coli Proteins
• Fermentation
• Gene Library
• Humans
• Nucleic Acid Hybridization
• Open Reading Frames (genetics)
• Polymerase Chain Reaction
• Sequence Analysis, DNA
• Sequence Homology, Nucleic Acid
• Shiga Toxins (biosynthesis, metabolism)
• Sorbitol (metabolism)