Prevalence of AmpC and Extended-Spectrum Beta-Lactamase-Producing Bacteria in Livestock and Poultry Environments in Southeast Nigeria

Antimicrobial resistance (AMR) occurs when microorganisms no longer respond to the therapeutic effects of antibiotics. Extended-spectrum beta-lactamase (ESBL) and AmpC enzymes are key factors in AMR, diminishing the effectiveness of essential antibiotics. This study investigated the detection and antimicrobial susceptibility of ESBL- and AmpC-producing bacteria found in environments associated with livestock and poultry. A combination of bacteriological and molecular methods was used for bacterial isolation and identification. Disk diffusion and PCR were used to confirm ESBL and AmpC production. ESBL-producing bacteria were detected in poultry samples at rates of 4%, 1%, and 2% in E. coli, Klebsiella species, and P. aeruginosa, respectively. In livestock samples, ESBL production was observed in E. coli (5%), Klebsiella species (2%), and P. aeruginosa (4%). AmpC-producing bacteria were found in E. coli (3%), Klebsiella species (2%), and P. aeruginosa (1%) in poultry environments, while in livestock environments, AmpC was detected in E. coli (7%), Klebsiella species (3%), and P. aeruginosa (6%). Both ESBL- and AmpC-positive strains showed a significant reduction in susceptibility to carbapenems and cephalosporins. PCR analysis revealed the presence of CTX-M-15 genes in 20% and FOX-1 genes in 25% of the bacteria, which are responsible for mediating resistance to ESBL and AmpC. These findings identify the key genetic factors contributing to bacterial resistance in Southeast Nigeria and emphasize the importance of continuous monitoring and surveillance to limit the spread of AMR, as it poses a significant risk to effective antibiotic treatments.