Detection of antimicrobial resistance genes in extended spectrum beta-lactamase-producing Escherichia coli from milk of indigenous Beetal goats of Punjab

Antimicrobial resistance (AMR) is a burning issue in the present era. Mastitis in dairy animals is one of the most important causes of huge production loss to dairy farmers.

The study aims to find the prevalence, antimicrobial resistance profile, and resistance genes in the extended-spectrum beta-lactamase-producing Escherichia coli in mastitic milk.

A total of 125 milk samples were collected from Beetal goats suffering from clinical mastitis from different districts of Punjab and processed for bacterial isolation and further identification. The drug resistance profile of ESBL-producing E. coli and its associations with molecular markers was analyzed using statistical analysis.

The prevalence of ESBL-producing E. coli in dairy goats of Punjab was recorded as 6.4%. The isolates showed the highest resistance to the beta-lactam group of antibiotics. The resistance percentages of streptomycin, gentamicin, tetracycline, chloramphenicol, clotrimazole, and colistin were 50%, 37.5%, 50%, 25%, 25%, and 50%, respectively. The isolates showed intermediate resistance to imipenem (12.5%) and tetracycline (25%). The ESBL-producing E. coli isolates harbored the resistance genes blaCTXM (100%), blaTEM (62.5%), blaSHV (25%), blaOXA (37.5%), tetA (37.5%), tetB (25%), aadA (37.5%), sul1 (25%), MOXM (12.5%), DHAM (25%), and blaCMY-2 (50%). Tetracycline and sulphonamide resistances were statistically associated with their respective resistance genes (P<0.05). Streptomycin resistance was not statistically associated with the presence of the aadA gene (P>0.05). The genes blaIMP and blaNDM were not recorded in any of the isolates. In this study, 12.5% of the isolates showed co-resistance to colistin and carbapenem.

Antimicrobial resistance is a hot topic and requires immediate attention.