Molecular confirmation of some virulence genes of E. coli isolated from lambs' colibacillosis

Colibacillosis is an infectious disease caused by pathogenic strains of E. coli, which are considered the most common and significant bacteria that cause dysentery or diarrhea in lambs. The objective of the present inquiry was to determine whether the bacterial isolates under examination possessed the principal virulence genes. The study entailed the cultivation of 65 E. coli isolates, identified through growth on chromogenic agar. Following a 24-hour culture on EMB agar at 37°C, all isolates were subjected to DNA extraction. In the present study, four genes uidA, stx1, stx2, and eaeA were amplified by the polymerase chain reaction using gene-specific primers. The current study's findings verified that all 65 isolates were E. coli based on the uidA gene. Sixty isolates (92.3%) had the stx1 gene, while 47 isolates (72.3%) had the stx2 gene. At the same time, the eaeA gene was detected in 17 isolated bacteria (26.15%). A total of 26.15% of the isolates incorporated all three virulence factors. Of the 65 E. coli isolates, 64 (98.5%) were enterohemorrhagic E. coli (EHEC). The enteropathogenic E. coli (EPEC) isolates did not exist in the current study. To conclude, colibacillosis is the most frequent and significant cause of dysentery and diarrhea in lambs in Mosul. The isolated bacteria exhibited a high level of virulence, represented by the presence of genes encoding Shiga toxins and Intimin. The highlight must be attention to the possibility of implicated of lambs as a reservoir for these zoonotic bacteria that cause several syndromic illnesses in humans.