Chlorhexidine Use Can Lead to Colistin Resistance

A recently published scientific study identifies a novel resistance mechanism to the widely used antiseptic, chlorhexidine, which fosters cross-resistance to Colistin, an antibiotic of last resort for treatment of carbapenem-resistant infections. The study shows that mutations conferring chlorhexidine resistance in Klebsiella pneumoniae lead to generation of mutations that result in Colistin resistance (Figure 1). Interestingly, this appears to be unidirectional − Colistin resistance does not lead to chlorhexidine resistance.

Based on these findings, eradicating Colistin-resistant Klebsiella isolates may become increasingly problematic given the current and increasingly broad use of chlorhexidine. While the study affirms Darwin − evolutionary pressure leads to the development of new resistance mechanisms – loss of an antibiotic of last resort like Colistin has wide-ranging and potentially lethal implications, including prolonging of outbreaks or leading to new outbreaks. This article highlights the challenges and should generate discussion about common infection control practices using chlorhexidine to prevent healthcare associated infections. Employing more vigilant anti-microbial resistance (AMR) monitoring, including sensitive and specific molecular diagnostics as early surveillance, may be one strategy to address the dilemma posed by these results and reduce the potential for AMR infections.

Click here for more on the study from Antimicrobial Agents and Chemotherapy.

Wand ME, Bock JL, Bonney LC, Sutton JM. Mechanisms of increased resistance to chlorhexidine and cross-resistance to colistin following exposure of Klebsiella pneumoniae clinical isolates to chlorhexidine. Antimicrob Agents Chemother. 2016 Oct 31. doi: 10.1128/AAC.01162-16 [Epub ahead of print].