Molecular Detection of Carbapenemase and Fluoroquinolone Resistance Genes in Pseudomonas aeruginosa Isolated from Hospital Waste

Hospital waste poses a significant environmental and public health threat due to its potential to harbour and spread antibiotic-resistant pathogens. Among these, Pseudomonas aeruginosa, a well-known opportunistic bacterium, is particularly concerning due to its multidrug resistance and ability to persist in hospital environments. This study aimed to determine the prevalence, antimicrobial resistance profiles, and molecular detection of carbapenem and fluoroquinolone resistance genes in P. aeruginosa isolated from hospital waste. A total of 60 hospital waste samples were aseptically collected from the laboratory, outpatient and surgery units of Nnamdi Azikiwe Medical Centre. Isolation and identification were performed using cetrimide agar and standard microbiological methods. Antimicrobial susceptibility testing was carried out using the Kirby-Bauer disk diffusion method in accordance with CLSI (2022) guidelines. PCR assays were conducted to detect the presence of carbapenemase (NDM, KPC) and fluoroquinolone (QnrA) resistance genes. Among the 60 samples analysed, 22 (36.7%) were confirmed as P. aeruginosa. High resistance rates were observed for levofloxacin (77.3%), ofloxacin (59.1%), ciprofloxacin (54.5%), imipenem (50%), and meropenem (40.9%). Six isolates (27.3%) were identified as multidrug-resistant. PCR analysis revealed the presence of the blaKPC, blaNDM, and QnrA genes among the isolates, indicating the presence of multiple resistance mechanisms. These findings demonstrated that hospital waste serves as a significant reservoir for multidrug-resistant P. aeruginosa, which carries clinically relevant resistance genes. Effective treatment of hospital waste, strict enforcement of infection control practices, and the implementation of antibiotic stewardship programs are essential to mitigate the environmental spread of antimicrobial resistance.