Determination of antibiotic resistance using three phenotypic methods in Campylobacter coli strains isolated from commercial chicken meat in Lima, Peru.

BACKGROUND

Motivation for the study. Campylobacter coli, a bacterium that causes gastroenteritis in humans through the consumption of contaminated chicken meat, has shown an increase in antibiotic resistance worldwide. In Peru, information on this is scarce, so we proposed to determine resistance and minimum inhibitory concentration (MIC) using three phenotypic methods. Main findings. In all methods, more than 70% of strains were multidrug resistant with a MIC ≥32 μg/mL, with plate microdilution being the most efficient method. Implications. C. coli strains from chicken carcasses had a high percentage of multidrug resistance. Continuous monitoring with a multisectoral approach encompassing human, animal, and environmental health is necessary.

OBJECTIVES.: To determine the resistance and minimum inhibitory concentration (MIC) of erythromycin, azithromycin, ciprofloxacin, and tetracycline in Campylobacter coli strains isolated from chicken carcasses sold in Lima, Peru.

MATERIALS AND METHODS.: Cryopreserved strains of C. coli (n=106) were reactivated and the concordance (Kappa coefficient) of the resistance and MIC results between the disk diffusion (DD), E-test (ET), and microdilution plate (MDP) tests was evaluated.

RESULTS.: Ninety-seven strains were reactivated, of which 94 to 100% were resistant to ciprofloxacin, erythromycin, and tetracycline, while only 58% were resistant to azithromycin in the DD test. The ET and MDP tests showed 78 to 100% of resistant strains, with azithromycin presenting the lowest percentage of resistance. More than 70% of strains were resistant to at least three antibiotics in all three tests. In addition, 50%, 69%, and 100% of strains had a MIC ≥ 32 μg/mL for ciprofloxacin, azithromycin, and tetracycline/erythromycin, respectively.

CONCLUSIONS.: C. coli strains from chicken carcasses had a high percentage of multidrug resistance. The concordance between the three tests was almost perfect, but the ET strips showed maximum concentrations that are insufficient for the MIC in these strains. It is recommended to perform resistance and MIC testing using the MDP, as it allows for a wider range of antibiotic concentrations to be used.

BACKGROUND

Motivation for the study. Campylobacter coli, a bacterium that causes gastroenteritis in humans through the consumption of contaminated chicken meat, has shown an increase in antibiotic resistance worldwide. In Peru, information on this is scarce, so we proposed to determine resistance and minimum inhibitory concentration (MIC) using three phenotypic methods. Main findings. In all methods, more than 70% of strains were multidrug resistant with a MIC ≥32 μg/mL, with plate microdilution being the most efficient method. Implications. C. coli strains from chicken carcasses had a high percentage of multidrug resistance. Continuous monitoring with a multisectoral approach encompassing human, animal, and environmental health is necessary.