Phenotypic and Genotypic Characterization of ESBL and AmpC β-Lactamase-Producing E. coli Isolates from Poultry in Northwestern Romania.

BACKGROUND/

OBJECTIVES

The widespread use of antibiotics in animal husbandry has led to an increase in antimicrobial-resistant Escherichia coli, particularly strains producing extended-spectrum β-lactamases (ESBL) and AmpC β-lactamases. This study aimed to isolate and characterize such strains from fecal samples of broiler chickens (n = 71) and slaughtered turkeys (n = 31) in northwestern Romania.

METHODS

Antimicrobial susceptibility testing and PCR were used to evaluate phenotypic resistance patterns and detect the presence of resistance genes (AmpC, blaZ, and blaTEM).

RESULTS

The results showed that 55% of turkey and 61% of broiler isolates were presumptive ESBL/AmpC producers. Among all isolates, 50% were classified as extensively drug-resistant (XDR), 44% as multidrug-resistant (MDR), and only 6% were fully susceptible. Gene detection revealed an overall prevalence of 44.2% for AmpC, 72.7% for blaZ, and 58.1% for blaTEM, yielding a total penetrance of 51.09%. The diagnostic odds ratio (DOR) values, ranging from 0.67 to 81, suggest the efficacy of the antibiotic susceptibility testing method used in detecting the presence of these resistance genes.

CONCLUSION

Overall, these findings highlight a significant burden of antimicrobial-resistant, poultry-associated E. coli strains, warranting stricter antimicrobial stewardship.