Pathogenicity-associated islands in extraintestinal pathogenic Escherichia coli are fitness elements involved in intestinal colonization

Diard, Médéric and Garry, Louis and Selva, Marjorie and Mosser, Thomas and Denamur, Erick and Matic, Ivan. (2010) Pathogenicity-associated islands in extraintestinal pathogenic Escherichia coli are fitness elements involved in intestinal colonization. Journal of Bacteriology, 192 (19). pp. 4885-4893.

Full text not available from this repository.

Official URL: https://edoc.unibas.ch/64702/

Downloads: Statistics Overview


The virulence of many human pathogens does not seem to be an evolutionarily selected trait, but an accidental by-product of the selection that operates in another ecological context. We investigated the possibility that virulence of the extraintestinal pathogenic Escherichia coli (ExPEC) strains, which frequently cause disease in the host in which they asymptomatically colonize the intestine, is the consequence of commensalism. Most of the ExPEC virulence factors are clustered on genomic islands called pathogenicity-associated islands (PAIs). We constructed and characterized several mutants of the ExPEC 536 strain with either (i) deletions of each single PAI or (ii) a complete deletion of all seven PAIs. In vitro phenotypic characterization of 536 mutants showed that the seven PAIs were dispensable for growth in the absence of external stress, as well as under a range of biologically relevant stressors, i.e., serum, bile, and oxidative, nitrosative, hyperosmotic, and acidic stress. However, challenge against the wild-type (WT) strain in a murine model shows that the deletion of all seven PAIs drastically reduces the fitness of 536 during persistent intestinal colonization. This defect seems to be linked to the hypermotility observed for mutants devoid of all seven PAIs. In addition, we show that PAIs diminish fitness of their carrier during growth in urine, suggesting that urinary tract infections are unlikely to provide selective pressure for the maintenance of ExPEC PAIs. Our results are in accordance with the coincidental-evolution hypothesis postulating that extraintestinal E. coli virulence is a by-product of commensalism.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Infection Biology > Pathogen Evolution (Diard)
UniBasel Contributors:Diard, Médéric
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Society for Microbiology
Note:Publication type according to Uni Basel Research Database: Journal article
Related URLs:
Identification Number:
Last Modified:02 Dec 2020 08:42
Deposited On:02 Dec 2020 08:42

Repository Staff Only: item control page