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ANNUAL CONFERENCE :: Abstract Library
Abstract Library
2003 Conference Abstract
| Type of Submission |
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Submission Type: |
Poster Presentation |
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Subject Category: |
Veterinary Microbiology |
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| Session Information |
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Presentation Date: |
May 26, 2003 |
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Abstract ID: |
G6 |
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Session: |
Poster 1 |
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Time: |
14:00 |
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| Presenting Author |
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| Other Authors |
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CM DOZOIS,
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| Title |
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Characterization of a Novel Fimbrial Operon from Avian Pathogenic Escherichia coli and Phylogenetic Distribution among E. coli Reference Strains. |
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| Abstract Text |
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Avian Pathogenic Escherichia coli (APEC) are an important cause of extra-intestinal diseases such as colisepticemia, cellulitis, and airsacculitis, and therefore prove to be a major problem to the poultry industry. The virulence factors used by these pathogens to cause disease are not yet fully understood. An important virulence mechanism is adherence and colonisation of the host tissues. We identified a sequence encoding a putative adhesin expressed in tissues of poultry infected with APEC strain chi7122 (O78: K80: H9) that is absent from E. coli K-12. The putative fimbrial operon was localized within a region flanked by genes corresponding to glmS and pstS of E. coli K-12. The region containing the in vivo transcribed fimbrial operon was cloned from a PCR fragment and sequenced. The deduced amino-acid sequence of the operon exhibits identity to putative fimbriae of E. coli O157:H7 and Salmonella typhi. A high-copy vector containing the novel fimbrial operon conferred an aggregative phenotype to an E. coli K-12 strain, indicating that this novel fimbria may contribute to cell-cell interactions. The role of these fimbriae in colonisation and cell interactions is currently being investigated. The prevalence of the operon among isolates was determined by PCR amplification of a segment of the gene encoding the usher. The presence of this novel fimbrial operon is associated with certain serogroups of E. coli that cause avian disease, particularly O7, O8, O9, and O78, and is rarely present in other serogroups associated with APEC such as O1, O2, and O18. Within the E. coli reference (ECOR) collection, it is associated with phylogenetic groups B1 and D. These results suggest that this operon may also serve as a differential diagnostic marker for APEC and other E. coli isolates. |
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