Phenotypic Antimicrobial Resistance Dynamics Across Varying Clinical Severity Scores of Ovine Footrot Lesions
DOI:
https://doi.org/10.52331/v32i1q953Keywords:
antimicrobial resistance; ovine footrot; clinical severityAbstract
Antimicrobial resistance is an ancient phenomenon and an increasing global threat affecting animal, human, and environmental health. Its emergence is largely driven by the extensive use of antimicrobials in medicine and agriculture, while bacterial mutations, natural evolution, and horizontal gene transfer further promote the acquisition and spread of resistance genes. This study investigates the phenotypic antimicrobial resistance (AMR) dynamics of opportunistic Gram-negative (n=355) and Gram-positive (n=198) bacteria isolated from ovine footrot lesions, stratified across five clinical severity scores. For Gram-negative isolates, advanced Score 5 lesions exhibited alarming resistance rates to Ampicillin (89.2%) and Amoxicillin/Clavulanic acid (76.6%), while Imipenem maintained a static, high-resistance ceiling (76%-81%, p = 0.442) across the entire clinical spectrum. Among Gram-positive bacteria, Benzylpenicillin resistance reached an absolute saturation threshold of 100% in Score 5 lesions, a trajectory closely mirrored by Ceftiofur (92.6%) and Gentamicin (88.9%), signaling a highly prevalent methicillin-resistant phenotype. In contrast, Florfenicol (13%-24.2%) and Sulfamethoxazole (22.6%-33.3%) sustained the lowest and most favorable resistance boundaries, remaining statistically unaltered by clinical progression (p ≥ 0.05).
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Copyright (c) 2026 Florina-Gheorghița Marian, Emoke Pall, Emilia Trif, Adrian Potârniche, Aurel Vasiu, Smaranda Crăciun, Marina Spînu
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