Fenotipska obilježja virulencije, enteropatogeni serovarovi i tvorba verotoksina sojeva bakterije E. coli izdvojenih iz pasa na Trinidadu u kojih nije ustanovljen proljev

The study was conducted to determine the prevalence and selected characteristics of Escherichia coli in non-diarrhoeic dogs from Trinidad. Rectal swabs or faecal samples were collected. Primary isolation of E. coli was done on eosin methylene blue (EMB) agar, haemolysin and mucoid production were detected on blood agar (BA) and sorbitol fermentation was assayed on sorbitol MacConkey agar (SMAC) agar. Agglutination tests, using commercially available antisera, determined O157-positive and enteropathogenic (EPEC) strains of E. coli while the vero cell assay detected verocytotoxigenic E. coli (VTEC) strains. Overall, of a total of 1,391 dogs sampled, E. coli was isolated from 1,266 (91.0%) dogs. Differences were statistically significant amongst E. coli isolated from dog sources (P<0.05; χ2) with the highest (96.0%) and lowest (81.3%) prevalence detected in hunting dogs and pound dogs, respectively. Of the 1,900 E. coli isolates tested, 100 (5.3%), 81 (4.3%) and 133 (7.0%) were mucoid, haemolytic and non-sorbitol fermenting (NSF) respectively. The difference was statistically significant (P<0.05; χ2). For EPEC strains, of the 333 E. coli isolates tested, 189 (56.8%) belonged to ‘enteropathogenic’ serogroups. The difference in prevalence across the various dog sources was statistically significant (P<0.05; χ2). Of the 558 E. coli strains tested, 74 (13.3%) were positive for verocytotoxin production. It was concluded that asymptomatic dogs in Trinidad carry virulent strains of E. coli, posing a threat as reservoirs of infections to human handlers and their owners and therefore are of significance for public health.Istraživanje je poduzeto radi određivanja prevalencije i određenih značajki bakterije Escherichia coli u pasa bez proljeva na Trinidadu. Pretraženi su bili uzorci obrisaka rektuma i izmeta. E. coli bila je izdvojena na eozinmetilensko plavilo agaru. Tvorba hemolizina i sluzi dokazivana je na krvnomu agaru, a fermentacija sorbitola na MacConkey sorbitolskom agaru. Serološka skupina O157 i enteropatogenost dokazani su aglutinacijskim testom pomoću komercijalnih antiseruma, dok su verocitotoksigeni sojevi dokazani testom na staničnoj kulturi VERO. E. coli bila je izdvojena iz 1266 (91,0%) od pretraženih 1391 psa. Statistički značajne razlike ustanovljene su u izdvajanju E. coli (P<0,05; χ2) s najvećom prevalencijom (96,0%) u lovačkih pasa i najmanjom (81,3%) u tornjaka. Od analiziranih 1900 izolata E. coli, 100 (5,3%) je imalo sluzave kolonije, 81 (4,3%) je bio hemolitičan, a 133 (7,0%) izolata nisu fermentirala sorbitol. Razlika je bila statistički značajna (P<0,05; χ2). Od 333 pretražena izolata, 189 (56,8%) ih je pripadalo enteropatogenim (EPEC) serološkim skupinama. Razlika je bila statistički značajna s obzirom na različito podrijetlo pretraženih pasa (P