COMPARATIVE ANTIMICROBIAL RESISTANCE PROFILES OF ESCHERICHIA COLI FROM FATTENING PIGS AND CALVES IN SPAIN: AN ISOLATE-LEVEL MIC ANALYSIS
DOI:
https://doi.org/10.65327/bp.v12i3.2534Keywords:
antimicrobial resistance, Escherichia coli, fattening pigs, calves, minimum inhibitory concentration, multidrug resistanceAbstract
Antimicrobial resistance in food-producing animals is an important concern for animal and public health, as commensal bacteria may act as reservoirs in livestock production systems. In this study, antimicrobial resistance profiles of commensal Escherichia coli (E. coli) collected from fattening pigs and calves in Spain were compared using isolate-level minimum inhibitory concentration (MIC) data. All 340 isolates (170 pig derived and 170 calf derived) were tested and evaluated against 15 antimicrobial agents. Resistance was determined using antimicrobial-specific surveillance interpretive thresholds, while between-group differences were assessed using chi-square or Fisher’s exact tests, odds ratios, multiple-testing correction, and multidrug-resistance analysis. The resistance levels to ampicillin, ciprofloxacin, trimethoprim, nalidixic acid, tetracycline, sulfamethoxazole and chloramphenicol were significantly higher for pig-derived isolates. The highest effect observed was for the drugs ciprofloxacin, ampicillin and trimethoprim. There were also significant variations in the source associated distributions for several agents in the MIC. Significantly more pig isolates had multidrug resistance (58.2%) than calf isolates (22.9%), and pigs had a higher burden of resistance. No resistance was observed against meropenem, colistin, amikacin, ceftazidime or tigecycline in either group. The results show a significantly higher antimicrobial-resistance burden in pig-derived E. coli and underscore the need to maintain isolate-level antimicrobial-resistance surveillance across livestock populations.
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Copyright (c) 2026 Dr. Fawzia Hassan A. Al Hamadi, Dr. Zulaikha Mohamed Al Hammadi, Dr. Saeed Mohamed S. Al Yammahi
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