Molecular detection of extended spectrum beta lactamase producing E. coli from diarrheic deer feces

Beta-lactamase-producing Escherichia coli pose a public health threat due to their resistance to a wide range of broad-spectrum antibiotics as third-generation cephalosporins. Fifty rectal swabs were obtained from diarrheal Fallow deers, over six months old, of both sexes in Mosul city between September 2024 and December 2025. The samples were sent off immediately to the Lab of Microbiology at the College of Veterinary Medicine under refrigerated and sterile conditions. MacConkey agar plus 2 µg/ml of cefotaxime (MA+) was used to culture all swabs, and methylene blue eosin agar was used to culture suspected colonies. This study indicated that 82% of the isolates were cefotaxime-resistant E. coli. The results were confirmed by polymerase chain reaction test and detect some of extended-spectrum beta-lactamase resistance genes. Molecular screening revealed that all isolates subjected to PCR 100% carried the Uid A gene specialized for E. coli. also, all isolates gave positive results for the resistance genes (CTX-M and TEM), but negative for the SHV gene. The current study revealed a high rate of isolation of E. coli that produced ESBLs with resistance genes (CTX-M, TEM) from the feces of deer with diarrhea, raising ecological and epidemiological concerns, as Fallow deer may serve as reservoirs or vectors of antimicrobial resistance, contributing to its spread in both natural ecosystems and human-associated environments.