Assessment of disinfectants efficacy on nosocomial bacteria and determining their minimum inhibitory concentration and minimum bactericidal concentration

Abstract

Background: Nosocomial infection are increasing daily. It is important to investigate the efficiency of popular Disinfectants and determine their Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) against nosocomial bacteria. Objective: This study aimed to investigate the efficiency of recommended amount of popular disinfectants Savlon, Dettol, Lizol and Savlon spray on nosocomial bacteria Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa and to determine the Minimum Inhibitory Concentrations (MIC) and Minimum Bactericidal Concentration (MBC) of Savlon, Dettol, Lizol and Savlon spray on nosocomial bacteria. Methods: The effects of the disinfectants of Savlon, Dettol, Lizol and Savlon spray against E. coli, S. aureus, K. pneumoniae and P. aeruginosa were investigated by dilution and cultured by spread plate method. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the disinfectants against total 12 isolates of E. coli, S. aureus, K. pneumoniae and P. aeruginosa bacteria were determined by dilution and cultured by spread plate method. Results: According to dilution and cultured by spread plate method and as per the recommendation of the company of disinfectants, each isolates had colonies or too numerous to count growth. In case of Dettol, the lowest MBC values were found from 750 μL to 1750 μL and lowest MIC values were found from 500 μL to 1500 μL for S. aureus and for E. coli the lowest MBC were found from 1000 μL to 1750 μL and lowest MIC were found from 750 μL to 1500 μL. Also, from 1500 μL to 2750 μL and from 1200 μL to 2500 μL were found to be the lowest MBC and MIC values for K. pneumonia. For P. aeruginosa isolate 1, the lowest MBC and MIC value is 5000 μL and 4750 μL, in case of Dettol. Regarding the results of Savlon, the lowest MBC and MIC values were found from 500 μL to 2750 μL and from 250 μL to 2500 μL for S. aureus. For E. coli the lowest MBC values were from 1250 μL to 3000 μL and lowest MIC values were from 1000 μL to 2750 μL. K. pneumoniae isolates lowest MBC values were from 500 μL to 4000 μL and lowest MIC values were from 250 μL to 3750 μL. In case of Lizol, the lowest MBC and MIC values were found from 765 μL to 1800 μL and from 750 μL to 1785 μL for S. aureus. For E. coli the lowest MBC values were found from 3015 μL to 3150 μL and the lowest MIC values were from 3000 to 3135 μL. In the matter of K. pneumoniae, the lowest MBC and MIC value was 915 μL and 900 μL. Unexpectedly, many isolates of these bacteria were found no MIC or MBC against these disinfectants. Conclusion: According to the findings, the recommendations amount of disinfectants do not work against nosocomial bacteria and the results of MIC and MBC are ten to twenty times higher than recommendations. Consequently, it can lead to health hazard as it may increase nosocomial infections. So, the companies should change their disinfectants efficiency in order to stop nosocomial infections.