Detection of carbapenem resistance genes in Campylobacter coli and Campylobacter jejuni isolated from chickens, and diarrheic children aged less than five years in Kampala city, Uganda

Campylobacter species are recognized as one of the significant causative agents of global foodborne illnesses and potential reservoirs for dissemination of antimicrobial resistance due to their zoonotic nature. Unlike other bacteria such as Klebsiella pneumoniae, E. coli, Enterobacter, etc., Campylobacter has shown limited or absent resistance to Carbapenems, critically important "last resort" antibiotics. This distinct resistance profile prompted this investigation into the prevalence of Carbapenem resistance genes in Campylobacter species, specifically Campylobacter coli (C. coli) and Campylobacter jejuni (C. jejuni). Analyses were conducted on 292 archived C. coli and C. jejuni isolates obtained from chickens and diarrheic children under five years of age in Kampala city, Uganda. The primary objectives included assessment of phenotypic susceptibility of the isolates to Meropenem and Imipenem using the Kirby Bauer disk diffusion method, as well as determination of the occurrence of four selected Carbapenem resistance genes (blaVIM, blaNDM-1, blaIMP, and blaOXA-48) using multiplex polymerase chain reaction (PCR). Interestingly, despite the observed phenotypic susceptibility to Meropenem and Imipenem in all the Campylobacter isolates, 29.8% harbored at least one of the four selected Carbapenem resistance genes, including blaVIM, blaNDM-1, blaIMP, and blaOXA-48. The prevalence of the resistance genes was 55(28.1%) in chickens and 15(38.5%) in children. Notably, blaVIM was the predominant gene, detected in 57.1% of the isolates, followed by blaNDM-1 (11.4%), blaIMP (8.6%), and blaOXA-48 (5.7%). Coexistence of multiple resistance genes was also observed, with blaVIM and blaIMP present in 10.0% of the isolates, and blaVIM and blaNDM-1 in 5.7%. One isolate displayed simultaneous presence of blaNDM-1, blaVIM, and blaIMP. This study uncovered a previously unexplored realm in Campylobacter research, identifying Carbapenem resistance genes in Campylobacter in Uganda. The identification of these resistance genes, despite the apparent phenotypic susceptibility to Carbapenems, signifies the presence of a substantial reservoir of carbapenem resistance genes in Campylobacter.