ABSTRACT
Escherichia coli may cause diseases in humans and animals, such as urinary infections, septicemia, meningitis and gastroenteritis. Asymptomatic dogs can participate in the epidemiologic chain as a reservoir of human pathogenic E. coli. The objective of the present study was to evaluate the occurrence of pathogenic E. coli in humans, on faeces of stray dogs without colibacillosis symptoms, and thus verify the participation of dogs as a source of human colibacillosis infection. Two hundred and twenty samples of faeces from animals captured by different Zoonotic Control Centers in São Paulo state, Brazil, were collected. These faeces, when submitted to microbiological exams, resulted in the isolation of 196 (80.09%) strains of E. coli, whose virulence genes were detected by PCR. At least one of the virulence factors studied was present in 123 (62.75%) strains. Sixteen (8.16%) were afa positive, 54 (27.55%) were positive to sta, 38 (19.38%) to pap, 66 (33.67%) to aer, 31 (15.81%) to cnf, 13 (6.63%) to hly, 1 (0.51%) to VT2, and none of the strains were positive for LT, STa or STb. Stray dogs which were apparently healthy could be participating in the epidemiologic chain as an E. coli reservoir uropathogenic to man, as the genes found in a higher frequency are present in extraintestinal infections, or more specifically, urinary infections.
KEY WORDS
Escherichia coli
; faeces; dogs; virulence factors; PCR