Reduced Chlorhexidine Susceptibility- Implication for Infection Prevention?
Chlorhexidine is a chemical antiseptic widely use in the hospital. It is effective in killing a wide range of pathogens, is safe and used as a primary agent of skin antisepsis. Here is a recent report, published in the Journal of Hospital Infection in drug resistant isolates of Klebsiella pneumonia.
We have observed the emergence of extremely-drug-resistant (XDR) strains of Klebsiella pneumoniae. The author's hypothesized that reduced susceptibility to chlorhexidine may contribute to the endemic nature of this strain.
The minimum inhibitory concentration (MIC) of chlorhexidine was determined in 126 XDR K. pneumoniae clinical isolates using agar dilution.
The MIC of chlorhexidine was higher for K. pneumoniae ST258 (N = 70) than other K. pneumoniae sequence types (N = 56); 99% of ST258 isolates had MICs >32 μg/mL, compared with 52% of other K. pneumoniae sequence types (P < 0.0001). Also, chlorhexidine-resistant subpopulations were observed independent of the bacterial sequence type or the MIC.
The suggestion? Reduced susceptibility to chlorhexidine may contribute to the success of XDR K. pneumoniae as a hospital acquired pathogen. This is a small study and definitely not conclusive. However, further surveillance of chlorhexidine susceptibility is definitely warranted to track its clinical significance.