Occurrence of FOX AmpC gene among Pseudomonas aeruginosa isolates in abattoir samples from south-eastern Nigeria

Abstract

In Nigeria, several investigations have been done about the prevalence of the AmpC enzyme in clinical isolates of Gram-negative bacteria; however, little information is available on the occurrence rate of this important enzyme in abattoir specimens that play a major role in the environmental pollution in Nigeria. This study aimed to evaluate the presence of FOX AmpC-producing Pseudomonas aeruginosa isolates from abattoir samples by both phenotypic method and polymerase chain reaction (PCR). In this study, 360 abattoir samples were analyzed for the isolation of P. aeruginosa strains. Antibiogram was carried out using the disk diffusion technique. The production of AmpC enzymes was phenotypically screened and confirmed using the cefoxitin--cloxacillin double-disk synergy test (CC-DDST). Finally, gene responsible for FOX AmpC enzyme production was investigated using PCR. A total of 147 (40.8%) isolates of P. aeruginosa was recovered from the abattoir samples. Ceftazidime and ciprofloxacin with 45.6 and 19% of susceptibility rates were the most and the less effective antibiotics, respectively. A total of 24 (16.3%) P. aeruginosa isolates were confirmed to phenotypically produce AmpC enzyme. However, the PCR result showed that only three (12.5%) of P. aeruginosa isolates harbored the FOX AmpC gene suggesting the attendance of other AmpC resistance genes. This study reported the first occurrence of P. aeruginosa isolates harboring the FOX AmpC gene in abattoir samples from south-eastern Nigeria. This incident requires the adoption of new policies and measures to prevent the further spread of strains carrying the AmpC gene.