Transmissible silver resistance readily evolves in high-risk clone isolates of Klebsiella pneumoniae

Silver is used extensively in both hospitals and outpatient clinics as a disinfectant coating agent on various devices. Resistance to silver was recently reported as an emerging problem in Enterobacteriaceae. Multidrug-resistant high-risk clones of Klebsiella pneumoniae are common causes of serious healthcare-associated infections worldwide posing a serious threat to patients. In this study, we investigated the capacity of both high-risk (CG14/15 and CG258) and minor clone strains of K. pneumoniae to develop resistance to silver. Resistance was induced in vitro in silver-susceptible but otherwise multidrug-resistant clinical isolates. Genetic alterations in the silver-resistant derivative strains with regard to the silver-susceptible isolates were investigated by whole-genome sequencing. The transferability of high-level resistance to silver was also tested. We demonstrated that the high-level resistance to silver can quickly evolve as a consequence of a single-point mutation either in the cusS gene of th...