Variable Chlorhexidine Minimal Inhibitory Concentrations (MICs) Across Klebsiella Species from a Single Facility

We assessed in vitro chlorhexidine Minimal Inhibitory Concentrations (MICs) across Klebsiellaspecies from a hospital with widespread chlorhexidine use. Isolates underwent MIC testing andwhole genome sequencing. Species showed varying resistance, with K. quasipneumoniae havingthe highest MICs. There was no clear link to acquired resistance but some species had morechromosomal efflux pumps. Differences in chlorhexidine MICs between species highlight therole that biocides could have in shaping microbial populations in the hospital environment.