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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

The Type VI Secretion System Plays a Role in Type 1 Fimbria Expression and Pathogenesis of an Avian Pathogenic Escherichia coli Strain

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Author(s):
de Pace, Fernanda ; Nakazato, Gerson ; Pacheco, Alline [1, 2] ; de Paiva, Jacqueline Boldrin ; Sperandio, Vanessa [1, 2] ; da Silveira, Wanderley Dias [3]
Total Authors: 6
Affiliation:
[1] Univ Texas SW Med Ctr Dallas, Dept Microbiol, Dallas, TX 75390 - USA
[2] Univ Texas SW Med Ctr Dallas, Dept Biochem, Dallas, TX 75390 - USA
[3] Campinas State Univ UNICAMP, Inst Biol, Dept Genet Evolut & Bioagents, Sao Paulo - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Infection and Immunity; v. 78, n. 12, p. 4990-4998, DEC 2010.
Web of Science Citations: 55
Abstract

Avian pathogenic Escherichia coli (APEC) strains frequently cause extraintestinal infections and are responsible for significant economic losses in the poultry industry worldwide. APEC isolates are closely related to human extraintestinal pathogenic E. coli (ExPEC) strains and may also act as pathogens for humans. Known APEC virulence factors include adhesins such as type 1 fimbriae and curli, iron acquisition systems, and cytotoxins. Here we show that APEC strain SEPT362, isolated from a septicemic hen, expresses a type VI secretion system (T6SS); causes cytoskeleton rearrangements; and invades epithelial cells, replicates within macrophages, and causes lethal disease in chicks. To assess the contribution of the T6SS to SEPT362 pathogenesis, we generated two mutants, hcp (which encodes a protein suggested to be both secreted and a structural component of the T6SS) and clpV (encoding the T6SS ATPase). Both mutants showed decreased adherence and actin rearrangement on epithelial cells. However, only the hcp mutant presented a mild decrease in its ability to invade epithelial cells, and none of these mutants were defective for intramacrophage replication. Transcriptome studies showed that the level of expression of type 1 fimbriae was decreased in these mutants, which may account for the diminished adhesion and invasion of epithelial cells. The T6SS seems to be important for the disease process, given that both mutants were attenuated for infection in chicks. These results suggest that the T6SS influences the expression of type 1 fimbriae and contributes to APEC pathogenesis. (AU)