Avian Extraintestinal Escherichia coli Exhibits Enterotoxigenic-Like Activity in the In Vivo Rabbit Ligated Ileal Loop Assay

Author(s)

Maluta, Renato Pariz ^[1] ; Viccari Gatti, Maria Silvia ^[1] ; Joazeiro, Paulo Pinto ^[2] ; de Paiva, Jacqueline Boldrin ^[1] ; Galvao Rojas, Thais Cabrera ^[1] ; Silveira, Flavio ^[1] ; Houle, Sebastien ^[3] ; Takayama Kobayashi, Renata Katsuko ^[4] ; Dozois, Charles M. ^[4] ; da Silveira, Wanderley Dias ^[1]

Affiliation

^[1] State Univ Campinas UNICAMP, Inst Biol, Dept Genet Evolut & Bioagents, Bacterial Mol Biol Lab, Sao Paulo - Brazil

^[2] State Univ Campinas UNICAMP, Inst Biol, Dept Histol, Sao Paulo - Brazil

^[3] Univ Quebec, Inst Armand Frappier, INRS, Laval, PQ - Canada

^[4] State Univ Londrina UEL, Ctr Biol Sci, Dept Microbiol, Londrina, Parana - Brazil

• Document type: Journal article
• Source: FOODBORNE PATHOGENS AND DISEASE; v. 11, n. 6, p. 484-489, JUN 2014.
• Web of Science Citations: 2

Abstract

Avian pathogenic Escherichia coli (APEC) strains harbor a number of virulence genes and cause extra-intestinal diseases, such as septicemia, swollen-head syndrome, salpingitis, and omphalitis in poultry. APEC strains are not known to cause intestinal diseases. Herein, for the first time, it is reported that APEC strains were able to induce an enterotoxigenic-like effect in rabbit ligated ileal loops. Strain SEPT362 caused cell detachment of the intestinal villi, which also showed a flattened and wilted appearance, but the integrity of the tight junctions was maintained. Additionally, this strain did not adhere to enterocytes in vivo, although adhesin encoding genes (fimH, csgA, lpfA2-3, and ECP) were present while other lpfA types, sfa, afa, papC, and ral genes were not. This enterotoxigenic-like activity was conserved after thermal treatment of the supernatant at 65 degrees C but not at 100 degrees C. Moreover, experiments based on filtering with different molecular weight cut-off (MWCO) pore sizes demonstrated that the component associated with the observed biological effect has a molecular weight > 100 kDa. Blast search and polymerase chain reaction assays for known E. coli virulence factors showed that strain SEPT362 harbors the gene encoding for the toxin EAST-1 and the serine protease autotransporter (SPATE) Tsh, but is negative for genes encoding for the toxins LT-I, STh, STp, Stx1, Stx2, CNF-1, CNF-2, CDT and the SPATEs Sat, Pic, Vat, SigA, SepA, EatA, EspP, or EspC. A cloned copy of the tsh gene in E. coli K-12 was also tested and was shown to have an enterotoxic effect. These results suggest that APEC might induce fluid accumulation in the rabbit gut. The Tsh autotransporter seems to be one of the factors associated with this phenotype. (AU)

• FAPESP's process: 12/04931-6 - Molecular characterization of avian pathogenic (APEC) and human uropathogenic (UPEC) Escherichia coli strains
• Grantee: Wanderley Dias da Silveira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/05073-3 - MOLECULAR CHARACTERIZATION OF AVIAN PATHOGENIC (APEC) AND HUMAN UROPATHOGENIC (UPEC) ESCHERICHIA COLI LINEAGES
• Grantee: Renato Pariz Maluta
• Support Opportunities: Scholarships in Brazil - Post-Doctoral