A helpful US study tracked the non-emergence of phenotypic or genotypic chlorhexidine resistance associated with hospital-wide use of chlorhexidine gluconate (CHG) antisepsis.

The 700 bed hospital introduced hospital wide CHG bathing in 2010, removed it in 2011, and reinstated it in 2015. They evaluated a collection of S. aureus isolates that were considered hospital-acquired and found that there was no reduction in CHG susceptibility during the two periods of CHG use, and found no evidence of qacA or qacB genes, which have been linked with reduced susceptibility to CHG. The study is one of the few that evaluated hospital-wide use of CHG, so there was certainly a pretty strong selective pressure for reduced susceptibility to emerge! Whilst this study does not prove that CHG is somehow ‘resistance-resistant’ – indeed, other studies have found evidence of reduced susceptibility associated with CHG use – it does reinforce that CHG is a well-tolerated antiseptic that does not readily promote reduced susceptibility.