Virulence potential of faecal <i>Escherichia coli</i> strains isolated from healthy cows and calves on farms in Perm Krai

Abstract

Cattle are a reservoir of pathogenic and potentially pathogenic Escherichia coli (E. coli) strains, which can pose a threat to human and animal health. The aim of the study was to evaluate the occurrence of 22 virulence-associated genes (VAGs), as well as the prevalence of antimicrobial drug resistance and three different bla-genes among 49 E. coli strains isolated from healthy cattle. The presence of VAGs that are common among diarrheagenic E. coli (DEC) strains and/or extraintestinal pathogenic E. coli (ExPEC) strains was determined by amplifying specific gene sequences by PCR. The following VAGs associated with DEC were found: east1 in 24.5 % of the studied E. coli strains, estI in 10.2 %, ehxA in 8.2 %, stx2 in 6.1 %, eltA in 4.1 %, estII and stx1 in 2.0 % of the studied strains. The prevalence of ExPEC VAGs was: fimH – 91.8 %, afa/draBC – 61.2 %, iutA – 44.9 %, flu – 32.7 %, sfaDE and hlyF – 30.6 %, iroN – 22.4 %, ompT and papC – 20.4 %, kpsMTII and hlyA – 18.4 %, iss – 14.3 %, usp – 2.0 %, cnf1 and iha were not detected among the studied strains. Based on the found co-occurrence of VAGs “classical”, hetero-pathogenic and hybrid-pathogenic E. coli strains were found. E. coli strains isolated from cows had a higher diarrheagenic potential, whereas E. coli strains isolated from calves more frequently contained genes associated with the ExPEC pathotype. Among the studied E. coli strains, 77.6 % were resistant to ampicillin, 49.0 % to tetracycline, 20.4 % to chloramphenicol, 16.3 % to cefoperazone, 16.3 % to ceftriaxone, 16.3 % to aztreonam, 14.3 % to cefepime, 10.2 % to norfloxacin, 10.2 % to ciprofloxacin, 6.1 % to levofloxacin and 2.0 % to gentamicin. All strains were sensitive to meropenem and amikacin. 32.7 % of the studied E. coli strains were found to be multidrug resistant, as they were resistant to at least three groups of antibiotics. With PCR, the blaTEM, blaSHV, and blaCTX-M genes were detected in 100, 31.6, and 26.3 %, respectively, of strains resistant to at least one of the beta-lactam antibiotics. Thus, it was shown that the studied faecal E. coli of healthy cows and calves had a high hetero-pathogenic potential, therefore in the future molecular genetic characterization of these bacteria shall be an important part of the epizootic monitoring.

Population characteristics of pathogenic Escherichia coli in puerperal metritis of dairy cows in Ningxia region of China: a systemic taxa distribution of virulence factors and drug resistance genes

“… Khalifeh and Obaidat (2022) observed that 97 and 32% of the bovine strains carried fimH and papC , respectively, and these strains typically carried two or more virulence genes. Additionally, Mihailovskaya et al (2022) reported that fimH (91.8%), afa (61.2%), iutA (44.9%), and papC (20.4%) were predominant in the virulence genes carried by ExPEC. In this study, we observed that the main virulence genes carried by E. coli were ompF (100%), traT (100%), fimH (97%), and papC (96%), and each strain contained multiple virulence genes.…”