Chlorhexidine leads to the evolution of antibiotic-resistant Pseudomonas aeruginosa

AbstractAntimicrobial resistance is a major public-health concern. We evaluate chlorhexidine role in selection of resistantPseudomonas aeruginosa mutants and their antibiotic cross-resistance. Mutation frequency and mutation rate after short-term exposure to sub-inhibitory concentrations of chlorhexidine were compared to those after spontaneous chlorhexidine-exposure, inP. aeruginosa PAO1 strain. Chlorhexidine-resistant mutants were generated, either by serial passage in increasing chlorhexidine concentrations or by single exposure to lethal chlorhexidine concentration. The generated mutants were tested for cross-resistance to different antibiotics, by determination of minimum inhibitory concentrations (MIC). The accompanied phenotypic changes in membrane permeability, outer membrane proteins (OMP), and efflux function were evaluated. The effect of exposure to chlorhexidine on MexAB-OprM, MexEF-oprN, and MexXY efflux pumps expression was investigated. No significant change was recorded between the mutation frequencies and mutation rates after short-term exposure to sub-inhibitory concentrations of chlorhexidine and after spontaneous chlorhexidine-exposure, inP. aeruginosa PAO1 strain. Twelve stable mutants, with  ≥ eight-fold increase in chlorhexidine MIC, were generated. Several mutants showed increase in the MIC of colistin, cefepime, ceftazidime, meropenem, ciprofloxacin, and amikacin; seven mutants expressed meropenem cross-resistance. This was accompanied by decrea...
Source: European Journal of Clinical Microbiology and Infectious Diseases - Category: Microbiology Source Type: research