Identification of enterotoxigenic virulence genes in calf originated escherichia coli isolates with neonatal septicemia

One of the important bacterial agents causing neonatal calf diarrhea is Enterotoxigenic E. coli (ETEC). The most important virulence factors in the pathogenesis of ETEC infections are fimbrial adhesins and enterotoxins. This study was conducted for the isolation of E. coli from calves with neonatal septicemia, its phenotypic and genotypic characterization, the determination of antibiotic resistance patterns, the determination of common serotypes and virulence factors in isolates. For this purpose, genotypic confirmation of isolates isolated from calves with neonatal septicemia and known phenotypically to be E. coli was investigated by PCR. O101, O9, O26, O145, O111 serotype genes, F17, F5, F41, ST, LT, EAST1 virulence genes and resistance genes of 8 different antibiotics in calves with septicemia in confirmed isolates analyzed by PCR. The resistance/sensitivity status to 8 different antibiotics formed were determined using the Kirby-Bauer standard disc diffusion test. As a result of the study, 95 (47.5% ) E. coli were isolated and identified from 200 stool samples. According to the phenotypic antibiotic resistance analysis, the isolates were 94.7% streptomycin, 93.7% tetracycline, 89.5% ampicillin, 87.4% trimethoprim-sulfamethoxazole, 87.4% chloromphenicol, 74.7% enrofloxacin, 62.1% gentamicin and 24.2% was found to be resistant to cephalothin. 88.4% of the isolates were tet(B), 74.7% sul3, 67.4% sul1, 61% cmlA, 56.8% qnr(B), 54.7% tet(A), 53.7% sul2, 38.9% CITM, 36.8% aadA1, 28.4% cat1, 26.3% qnr(S), 12.6% aac[3]-IV, 5.3% tet(C) and qnr(A) genes were detected in 1.05%. No blaSHV gene could be detected in any of the isolates. According to the presence of O101, O26 and O145 serotype genes, the isolates were found to be 33.7%, 6.3% and 2.1%, respectively, as a result of serogenotyping. O111 and O9 serotypes were not detected in any of the isolates. As a result of PCR studies carried out to determine virulence genes; It was determined that 23.2% isolates had East1, 22.1% isolates F5, 20% isolates STa, 17 isolates 17.9% F41 and 3.2% isolates LT. Thus, the presence, prevalence of ETEC in calves with neonatal septicemia in the sampling region, the pathotype/virotype distribution of the isolates were determined, and the relationship between these virulence factors and the disease was determined, and the most appropriate antibiotic option that could be used in the treatment of the disease was determined. It was concluded that the data obtained within the scope of the study could contribute to domestic and national vaccine studies later on.