Abstract
The rising global prevalence of antibiotic resistance (ABR) in bacteria, particularly in food producing animals, poses a substantial threat to both veterinary and human public health. Escherichia coli serves as a crucial indicator for monitoring ABR dissemination. This study aimed to identify β-lactam and tetracycline antibiotic resistance genes in E. coli isolates collected from sheep (n=66) and goats (n=54) in Quetta, Balochistan, Pakistan. Fecal samples (n=120 total) were collected aseptically, and E. coli isolates were identified through standard microbiological methods, including selective plating on EMB agar and Gram staining. Antibiotic Susceptibility Testing (AST) by the Kirby-Bauer disc diffusion method revealed alarmingly high rates of phenotypic resistance. Molecular detection of resistance genes by Polymerase Chain Reaction (PCR) further confirmed these phenotypic findings. Five genes were targeted: uidA (E. coli species marker), tetA, tetB (tetracycline resistance), blaTEM, and blaCTXM (β-lactam resistance). The uidA gene was detected in 79.2% (95/120) of all isolates. Resistance genes were highly prevalent: tetA was found in 76.6% (92/120) of isolates, tetB in 73.3% (88/120), blaTEM in 69.1% (83/120), and blaCTXM in 62.5% (75/120). This study underscores the significant burden of β-lactam and tetracycline resistance genes in E. coli. These results provide crucial data for implementing targeted antimicrobial management programs and efforts to manage the spread of antimicrobial resistance.
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