Frequency of Cytolethal Distending Toxin Genes in <i>Escherichia coli</i> Isolates from Bovine Mastitis in Tabriz City in 2020

Abstract

Background: Cytolethal distending toxin (CDT) gene is one of the important virulence factors in Escherichia coli isolated from different human and animal sources strains. Objectives: The aim of this study was to investigate the frequency of CDT genes in E. coli isolates 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. coli from bovine mastitis, the frequency of cdt-I, cdt-III, and cdt-IV genes was assessed by PCR method. Results: Of a total of 100 tested E. coli samples, 94 isolates were confirmed as E. coli by PCR test. Of the 96 E. coli isolates, none had the cdt-I, cdt-III, and cdt-IV genes. Conclusions: The results of this study showed that the frequency of the cdt gene in E. coli isolates from cow mastitis is very low, like the other animal sources in past studies.