Occurrence of Carbapenemase Resistance genes in hospital wastewater from selected facilities in Ibadan, Oyo State, Nigeria

The extensive misuse of antibiotics, insufficient wastewater treatment, and the direct release of hospital effluents into the environment in Nigeria contribute to the spread of clinically significant antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Consequently, continuous environmental bacteriological monitoring has become essential for producing trustworthy information regarding the prevalence and distribution of antimicrobial-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs) in environmental matrices. This research was aimed at investigating carbapenemase resistance genes in Gram-negative bacteria isolated from selected hospital wastewaters in Ibadan, Nigeria. Selected resistance genes were screened for by Polymerase Chain Reaction (PCR) amplification using primers targeting the genes of interest. All fifty-four screened isolates were resistant to ceftazidime. Sulphamethoxazole trimethoprim, azithromycin, cefotaxime, oxacillin, and cefepime resistance percentages were 64.81 %, 74.07%, 59.26%, 53.70%, and 31.48%, respectively. Resistance to streptomycin was 77.78%, while resistance to ciprofloxacin and cefoxitin was 38.89% and 25.93%, respectively. Imipenem had the lowest percentage of resistance, 20.37 %. The bla VIM gene was one of the most common ARGs detected by PCR among the isolates, with a percentage frequency of 12.96 % (7/54), followed by bla NDM with a frequency of 3.7 % (2/54). The percentage frequency of bla IMP and bla KPC was both 1.85 % (1/54). In one of the Klebsiella species isolated, multiple resistance genes ( bla VIM, KPC, IMP ) were discovered. This study established the role of hospital wastewater on the proliferation of ARBs and ARGs outside of hospitals.