Assessment of the Susceptibility of Chlorhexidine to Specific Microorganisms

Abstract

Objectives: This study aimed to identify the range of susceptibility of E. coli, S. enterica, P. aeruginosa, and S. aureus to chlorhexidine. Methods: First, an antibacterial evaluation was conducted using the zone of inhibition by disc diffusion method. For the statistical analyses, Shapiro-Wilk was used to verify normality, Kruskal-Wallis' H analysis was performed for comparison between groups, and Bonferroni was carried out as a post-hoc analysis. Results: The zone of inhibition for each concentration of chlorhexidine by disc diffusion was different for each strain at 2%, 1%, and 0.1% (p<0.05). The Minimal Inhibitory Concentration (MIC) of chlorhexidine were 0.003% for E. coli, 0.005% for S. enterica, 0.009% for P. aeruginosa, and 0.006% for S. aureus; the Minimal Bactericidal Concentration (MBC) was measured as 0.1% for E. coli, 0.1% for S. enterica, 0.2% for P. aeruginosa, and 0.1% for S. aureus. Conclusions: The results of this study confirmed that the disc diffusion, MIC, MBC, and sensitivity of chlorhexidine to specific microorganisms are different depending on the microorganism type. Therefore, in the hospital environment, frequently used disinfectants should be managed more frequently, and susceptibility evaluation should be monitored more regularly.