Open AccessRelationship between the Tsh Autotransporter and Pathogenicity of Avian Escherichia coli and Localization and Analysis of the tsh Genetic Region
Author(s) -
Charles M. Dozois,
Maryvonne Dho-Moulin,
Annie Brée,
John M. Fairbrother,
Clarisse Désautels,
Roy Curtiss
Publication year - 2000
Publication title -
infection and immunity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.508
H-Index - 220
eISSN - 1070-6313
pISSN - 0019-9567
DOI - 10.1128/iai.68.7.4145-4154.2000
Subject(s) - virulence , biology , pathogenic escherichia coli , plasmid , microbiology and biotechnology , escherichia coli , pathogenicity island , enterobacteriaceae , hemagglutinin (influenza) , gene , colicin , mutant , virology , genetics
The temperature-sensitive hemagglutinin Tsh is a member of the autotransporter group of proteins and was first identified in avian-pathogenicEscherichia coli (APEC) strain χ7122. The prevalence oftsh was investigated in 300E. coli isolates of avian origin and characterized for virulence in a 1-day-old chick lethality test. Results indicate that among thetsh -positive APEC isolates, 90.6% belonged to the highest virulence class. Experimental inoculation of chickens with χ7122 and an isogenictsh mutant demonstrated that Tsh may contribute to the development of lesions within the air sacs of birds but is not required for subsequent generalized infection manifesting as perihepatitis, pericarditis, and septicemia. Conjugation and hybridization experiments revealed that thetsh gene is located on a ColV-type plasmid in many of the APEC strains studied, including strain χ7122, near the colicin V genes in most of these strains. DNA sequences flanking thetsh gene of strain χ7122 include complete and partial insertion sequences and phage-related DNA sequences, some of which were also found on virulence plasmids and pathogenicity islands present in variousE. coli pathotypes and other pathogenic members of theEnterobacteriaceae . These results demonstrate that thetsh gene is frequently located on the ColV virulence plasmid in APEC and suggest a possible role of Tsh in the pathogenicity ofE. coli for chickens in the early stages of infection.