Determination of the genetic basis for MIT/CMIT detoxification

Reduced susceptibility to the isothiazolinone biocide MIT/CMIT was observed in Klebsiella oxytoca complex isolates obtained from a liquid soap that contained MIT/CMIT as a preservative. The genetic determinants of the reduced susceptibility are located on a roughly 80 kb plasmid (pKoxc_13-74-894_ars_gst). This plasmid is mobile as observed by plasmid transfer to other species. Plasmid sequencing and cloning of genes underlying this phenotype revealed that a reaction with glutathione is used to detoxify MIT/CMIT.