Virulence factors of avian pathogenic Escherichia coli isolated from broilers from the south of Brazil.
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.
da Rocha
Ana Cristina Gonçalves Pinto
AC
Universidade Federal do Rio Grande do Sul, Centro de Diagnóstico e Pesquisa em Patologia Aviária, Porto Alegre, Brazil.
da Silva
Ari Bernardes
AB
de Brito
A Benito Guimarães
AB
Moraes
Hamilton Luiz de Souza
HL
Pontes
Alexandre Pontes
AP
Cé
Milene Cristine
MC
do Nascimento
Vladimir Pinheiro
VP
Salle
Carlos Tadeu Pippi
CT
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
D003087:Colicins; D006460:Hemolysin Proteins