Evaluation of Disinfectant Efficacy and Antimicrobial Resistance in Nosocomial Pathogens with Emphasis on Pseudomonas aeruginosa

Background: This study aimed to assess the efficacy of selected disinfectants in Benghazi Medical Center hospital in Libya.
Materials & Methods: A total of 64 swabs were collected from healthcare workers’ hands, and 96 samples were collected from the hospital environment. Five bacterial species isolated from these samples were selected to investigate the bactericidal efficacy of
five disinfectants. Bacterial suspensions were prepared in 9 mL of broth medium and mixed with 1 mL of each disinfectant. All inoculated nutrient agar and MacConkey agar plates were incubated overnight at 37 °C. Bactericidal efficacy was assessed based on
colony growth. Phenotypic expression of ESBLs (extended spectrum beta lactamases) and MBLs (metallo beta-lactamases) was assessed in all bacterial isolates. Antimicrobial resistance genes were detected by PCR (polymerase chain reaction).
Findings: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Micrococcus spp., and Klebsiella pneumonia were isolated and identified by microbiological and biochemical tests. All isolates were found to be multidrug-resistant (MDR). The tested disinfectants demonstrated high bactericidal efficacy against these isolates. However, P. aeruginosa was not affected by hydrogen peroxide and alcohol, and methicillin-resistant S. aureus survived in iodine-containing medium. Notably, P. aerugino
sa isolates were detected as MDR strains in various hospital environments, including floors, wash basins, and even people’s hands and disinfectant bottles.
Conclusion: The selection of appropriate disinfectants (or chemical sterilants) is crucial and should be based on their proven efficacy against microbial agents. Proper testing is essential to ensure the effectiveness of disinfectants and antibiotics and to prevent the dissemination of resistant bacteria within hospital environments.