title: Virulence factors of avian pathogenic Escherichia coli isolated from broilers from the south of Brazil.
abstract: Sixty-three Escherichia coli strains isolated from broilers with respiratory problems were examined for virulence factors, hemolysin synthesis ability, motility, hemagglutination capacity, operon pap presence, colicin production, and serum resistance. The capacity to hemagglutinate guinea pig erythrocytes was found in 53 (84.1%) of the samples, but only 30 (47.6%) agglutinated chicken erythrocytes. D-mannose-sensitive hemagglutination against guinea pig erythrocytes was found in 19 (30.2%) samples and against chicken erythrocytes, in 15 (23.8%) samples, whereas the D-mannose-resistant hemagglutination with guinea pig erythrocytes was found in 34 (54%) samples, and 13 of these (20.6%) showed this characteristic against chicken erythrocytes. Operon pap, P fimbria codifier, was detected in 26 samples in a total of 34 D-mannose-resistant samples. Colicin production was observed in 55 (87.3%) of the strains, and 41.8% presented V colicin production. Of the samples analyzed, 56 (88.9%) presented serum resistance, six (9.5%) were intermediate, and only one (1.6%) was sensitive to the action of the complement. The diversity of virulence profiles detected in the samples in this study explains in part the multifactorial characteristics of avian colibacillosis.
authors.affiliation: Universidade Federal do Rio Grande do Sul, Centro de Diagnóstico e Pesquisa em Patologia Aviária, Porto Alegre, Brazil.
authors.forename: Ana Cristina Gonçalves Pinto
authors.initials: AC
authors.lastname: da Rocha
authors.forename: Ari Bernardes
authors.initials: AB
authors.lastname: da Silva
authors.forename: A Benito Guimarães
authors.initials: AB
authors.lastname: de Brito
authors.forename: Hamilton Luiz de Souza
authors.initials: HL
authors.lastname: Moraes
authors.forename: Alexandre Pontes
authors.initials: AP
authors.lastname: Pontes
authors.forename: Milene Cristine
authors.initials: MC
authors.lastname: Cé
authors.forename: Vladimir Pinheiro
authors.initials: VP
authors.lastname: do Nascimento
authors.forename: Carlos Tadeu Pippi
authors.initials: CT
authors.lastname: Salle
mesh_terms: D000818:Animals; D001938:Brazil; D002645:Chickens / Q000382:microbiology*; D003087:Colicins / Q000096:biosynthesis; D004912:Erythrocytes / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D010861:Fimbriae, Bacterial / Q000235:genetics; D006168:Guinea Pigs; D006386:Hemagglutination Tests / Q000662:veterinary; D006460:Hemolysin Proteins / Q000096:biosynthesis; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011201:Poultry Diseases / Q000382:microbiology*; D012141:Respiratory Tract Infections / Q000382:microbiology / Q000662:veterinary*; D014774:Virulence
chemical_list: D003087:Colicins; D006460:Hemolysin Proteins