Characterisation of atypical enteropathogenic <it>E. coli </it>strains of clinical origin
<p>Abstract</p> <p>Background</p> <p>Enteropathogenic <it>E. coli </it>(EPEC) is a prominent cause of diarrhoea, and is characterised in part by its carriage of a pathogenicity island: the locus for enterocyte effacement (LEE). EPEC is divided into two subty...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
BMC
2009-06-01
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| Series: | BMC Microbiology |
| Online Access: | http://www.biomedcentral.com/1471-2180/9/117 |
| _version_ | 1819122477497843712 |
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| author | Tennant Sharon M Tauschek Marija Azzopardi Kristy Bigham Andrea Bennett-Wood Vicki Hartland Elizabeth L Qi Weihong Whittam Thomas S Robins-Browne Roy M |
| author_facet | Tennant Sharon M Tauschek Marija Azzopardi Kristy Bigham Andrea Bennett-Wood Vicki Hartland Elizabeth L Qi Weihong Whittam Thomas S Robins-Browne Roy M |
| author_sort | Tennant Sharon M |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Enteropathogenic <it>E. coli </it>(EPEC) is a prominent cause of diarrhoea, and is characterised in part by its carriage of a pathogenicity island: the locus for enterocyte effacement (LEE). EPEC is divided into two subtypes according to the presence of bundle-forming pili (BFP), a fimbrial adhesin that is a virulence determinant of typical EPEC (tEPEC), but is absent from atypical EPEC (aEPEC). Because aEPEC lack BFP, their virulence has been questioned, as they may represent LEE-positive Shiga toxin-producing <it>E. coli </it>(STEC) that have lost the toxin-encoding prophage, or tEPEC that have lost the genes for BFP. To determine if aEPEC isolated from humans in Australia or New Zealand fall into either of these categories, we undertook phylogenetic analysis of 75 aEPEC strains, and compared them with reference strains of EPEC and STEC. We also used PCR and DNA hybridisation to determine if aEPEC carry virulence determinants that could compensate for their lack of BFP.</p> <p>Results</p> <p>The results showed that aEPEC are highly heterogeneous. Multilocus sequence typing revealed that 61 of 75 aEPEC strains did not belong to known tEPEC or STEC clades, and of those that did, none expressed an O:H serotype that is frequent in tEPEC or STEC strains associated with disease. PCR for each of 18 known virulence-associated determinants of <it>E. coli </it>was positive in less than 15% of strains, apart from NleB which was detected in 30%. Type I fimbriae were expressed by all aEPEC strains, and 12 strains hybridised with DNA probes prepared from either <it>bfpA </it>or <it>bfpB </it>despite being negative in the PCR for <it>bfpA</it>.</p> <p>Conclusion</p> <p>Our findings indicate that clinical isolates of aEPEC obtained from patients in Australia or New Zealand are not derived from tEPEC or STEC, and suggest that functional equivalents of BFP and possibly type I fimbriae may contribute to the virulence of some aEPEC strains.</p> |
| first_indexed | 2024-12-22T06:53:05Z |
| format | Article |
| id | doaj.art-98a4548954ff4ce5a629dc26924c7a06 |
| institution | Directory Open Access Journal |
| issn | 1471-2180 |
| language | English |
| last_indexed | 2024-12-22T06:53:05Z |
| publishDate | 2009-06-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Microbiology |
| spelling | doaj.art-98a4548954ff4ce5a629dc26924c7a062022-12-21T18:35:04ZengBMCBMC Microbiology1471-21802009-06-019111710.1186/1471-2180-9-117Characterisation of atypical enteropathogenic <it>E. coli </it>strains of clinical originTennant Sharon MTauschek MarijaAzzopardi KristyBigham AndreaBennett-Wood VickiHartland Elizabeth LQi WeihongWhittam Thomas SRobins-Browne Roy M<p>Abstract</p> <p>Background</p> <p>Enteropathogenic <it>E. coli </it>(EPEC) is a prominent cause of diarrhoea, and is characterised in part by its carriage of a pathogenicity island: the locus for enterocyte effacement (LEE). EPEC is divided into two subtypes according to the presence of bundle-forming pili (BFP), a fimbrial adhesin that is a virulence determinant of typical EPEC (tEPEC), but is absent from atypical EPEC (aEPEC). Because aEPEC lack BFP, their virulence has been questioned, as they may represent LEE-positive Shiga toxin-producing <it>E. coli </it>(STEC) that have lost the toxin-encoding prophage, or tEPEC that have lost the genes for BFP. To determine if aEPEC isolated from humans in Australia or New Zealand fall into either of these categories, we undertook phylogenetic analysis of 75 aEPEC strains, and compared them with reference strains of EPEC and STEC. We also used PCR and DNA hybridisation to determine if aEPEC carry virulence determinants that could compensate for their lack of BFP.</p> <p>Results</p> <p>The results showed that aEPEC are highly heterogeneous. Multilocus sequence typing revealed that 61 of 75 aEPEC strains did not belong to known tEPEC or STEC clades, and of those that did, none expressed an O:H serotype that is frequent in tEPEC or STEC strains associated with disease. PCR for each of 18 known virulence-associated determinants of <it>E. coli </it>was positive in less than 15% of strains, apart from NleB which was detected in 30%. Type I fimbriae were expressed by all aEPEC strains, and 12 strains hybridised with DNA probes prepared from either <it>bfpA </it>or <it>bfpB </it>despite being negative in the PCR for <it>bfpA</it>.</p> <p>Conclusion</p> <p>Our findings indicate that clinical isolates of aEPEC obtained from patients in Australia or New Zealand are not derived from tEPEC or STEC, and suggest that functional equivalents of BFP and possibly type I fimbriae may contribute to the virulence of some aEPEC strains.</p>http://www.biomedcentral.com/1471-2180/9/117 |
| spellingShingle | Tennant Sharon M Tauschek Marija Azzopardi Kristy Bigham Andrea Bennett-Wood Vicki Hartland Elizabeth L Qi Weihong Whittam Thomas S Robins-Browne Roy M Characterisation of atypical enteropathogenic <it>E. coli </it>strains of clinical origin BMC Microbiology |
| title | Characterisation of atypical enteropathogenic <it>E. coli </it>strains of clinical origin |
| title_full | Characterisation of atypical enteropathogenic <it>E. coli </it>strains of clinical origin |
| title_fullStr | Characterisation of atypical enteropathogenic <it>E. coli </it>strains of clinical origin |
| title_full_unstemmed | Characterisation of atypical enteropathogenic <it>E. coli </it>strains of clinical origin |
| title_short | Characterisation of atypical enteropathogenic <it>E. coli </it>strains of clinical origin |
| title_sort | characterisation of atypical enteropathogenic it e coli it strains of clinical origin |
| url | http://www.biomedcentral.com/1471-2180/9/117 |
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