Investigation of virulence factors, phylogenetic grouping, multiple-locus variable number tandem repeat analysis, and antimicrobial susceptibility of E. coli isolated from aborted bovine fetal tissue

Escherichia coli is an important microorganism for cattle breeding. The aim of this study was to investigate the presence of phylogenetic groups, virulence factors, genotyping with multi-locus variable tandem repeat analysis (MLVA), and susceptibility to commonly used antimicrobial agents in E. coli strains isolated from aborted bovine fetal samples. In this study, phylogrouping and various virulence genes were analyzed by PCR in E. coli strains isolated from 637 bovine fetal tissue samples. Consequently, E. coli was isolated and identified in 24 samples in culture. Of the 24 isolates identified as positive, 12.5% were defined as group A, 83.3% as B1, and 4.2% as group B2. Of the E. coli isolates, virulence factor fimH was identified in eight (33.3%), traT in 15 (62.5%), ompT in five (20.8%), CNF1 in one (4.16%), and CNF2 in six (25%). Seven genotypic groups were determined as a result of the analysis with the MLVA 10 method. According to the antimicrobial susceptibility test results, high resistance was determined against amoxicillin/clavulanic acid and oxytetracycline. In conclusion, strains of E. coli containing CNF1, CNF2, fimH, traT, and ompT virulence factors can be associated with bovine abortions. It is noteworthy that the dominant phylogenetic group B1 has been observed in cases of cattle abortions.