Biological characteristics and pathogenicity of avian Escherichia coli strains.
Fifty avian (chicken) pathogenic Escherichia coli strains (APEC) isolated from individuals suffering from omphalitis, septicaemia and swollen head syndrome, and 30 strains isolated from healthy chickens were studied regarding their biological characteristics such as serogroups, haemolysin, colicin, cytotoxin, toxin and siderophore production, adhesion capacity to in vitro cultivated cells, and absorption of Congo red dye. Serotyping demonstrated that most of the omphalitis and normal strains were untypable, whereas most of the septicaemic strains were either untypable or rough. There was no prevalent serogroup among the pathogenic strains studied. The capacity for adhesion and invasion of in vitro cultured cells (HeLa, HEp-2, KPCC), as well as the agglutination of different types of red blood cells and the LD50 of each strain were also evaluated. No correlation was observed between the biological characteristics and pathogenicity, except that colicin was characteristically produced by swollen head syndrome E. coli strains. No correlation was found between adhesion or haemagglutination patterns and pathogenicity. Only six of the 50 strains revealed invasive capacity and the strain that best invaded the cell lines was the one with the lowest LD50.
Dias da Silveira
Wanderley
W
Department of Microbiology and Immunology IB, Biology Institute, State University of Campinas, CP 6109, CEP 13081-970 Campinas, SP Brazil. wds@obelix.unicamp.br
Ferreira
Alessandra
A
Brocchi
Marcelo
M
Maria de Hollanda
Luciana
L
Pestana de Castro
Antonio Fernando
AF
Tatsumi Yamada
Aureo
A
Lancellotti
Marcelo
M
D000372:Agglutination Tests / Q000662:veterinary; D000818:Animals; D001422:Bacterial Adhesion / Q000502:physiology; D001427:Bacterial Toxins / Q000378:metabolism; D002478:Cells, Cultured; D002645:Chickens; D004926:Escherichia coli / Q000145:classification* / Q000472:pathogenicity / Q000502:physiology; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D006367:HeLa Cells; D006801:Humans; D007928:Lethal Dose 50; D011201:Poultry Diseases / Q000382:microbiology*; D012703:Serotyping; D014774:Virulence
D001427:Bacterial Toxins