frequency of cytolethal distending toxin genes in escherichia coliisolates from bovine mastitis in tabriz city in 2020

Background: cytolethal distending toxin (cdt) gene is one of the important virulence factors in escherichia coliisolated from different human and animal sources strains. objectives: the aim of this study was to investigate the frequency of cdt genes in e. coliisolates from bovine mastitis in tabriz city (east azarbaijan province) in 2020. methods: in this cross-sectional descriptive study, after isolation and biochemical and molecular identification of 100 e. colifrom bovine mastitis, the frequency of cdt-i, cdt-iii, and cdt-ivgenes was assessed by pcr method. results: of a total of 100 tested e. colisamples, 94 isolates were confirmed as e. coliby pcr test. of the 96 e. coliisolates, none had the cdt-i, cdt-iii, and cdt-ivgenes. conclusions: the results of this study showed that the frequency of the cdtgene in e. coliisolates from cow mastitis is very low, like the other animal sources in past studies.