Effectiveness of commonly used disinfectants in hospitals against common nosocomial bacteria

Abstract

Nosocomial infections, commonly acquired during hospital stays, pose a significant threat to patient safety and increase healthcare costs. The effective use of disinfectants is crucial for decreasing the transmission of nosocomial bacteria in healthcare settings. This thesis paper aimed to evaluate the effectiveness of various commonly used disinfectants in hospitals against 4 most common nosocomial bacteria (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Acinetobacter sp. ), providing valuable insights for infection control practices. In this study, swab samples were collected before and after the application of disinfectants from two government hospitals and two private hospitals. The surfaces selected for sampling included the operating table in the operation theatre and the floors of the wards, as these areas are where patients typically spend most of their time. The disinfectants that were used during this study were Savlon, Hexisol, Clotex, Shinex, and Perfume Phenyle. Two types of samples were collected from each area: one before and one after the application of disinfectants for surface cleaning. S. aureus, E. coli, K. pneumoniae, and Acinetobacter sp. were isolated from the collected samples using selective media. Samples were then subjected to serial dilution to find the effectiveness of the disinfectants. The decrease in the number of microbes before and after surface disinfection was quantified using log reduction. The highest log reduction was Perfume Phenyle in the case of the ward as it was able to achieve a 100% reduction percentage. Clotex on the other side was able to only kill 50% of the microbes. In the case of operation theatre, Hexisol was the most effective one with a 100% reduction whereas Clotex was not effective at all as it had a 0% percentage reduction. After that, the isolates were tested for non-susceptible testing, where different concentrations of the disinfectants were applied to determine the zone of inhibition. The inhibition zones were measured to compare the resistance rate of the disinfectants. The results indicated that Shinex and Savlon exhibited strong inhibitory effects on the growth of the isolates, even at reduced concentrations (60% of their concentrations). Conversely, Perfume Phenyle demonstrated more resistance, with minimal or no inhibition zones observed even at the recommended concentration. Hexisol showed comparatively higher resistance even when its high concentrations were used and no concentration was observed to be resistant less than 50% in any concentrations. Whereas, Clotex works up to 90% of its concentration. Among the tested microbes, S. aureus displayed less resistance than the others, even at lower concentrations of disinfectants. In conclusion, this study highlights the varying efficacy of different disinfectants against nosocomial bacteria. Shinex and Savlon demonstrated notable effectiveness, while Perfume Phenyle exhibited no efficacy. These findings provide valuable insights into the selection and utilization of disinfectants for effective infection control in healthcare settings.