새로운 플루오로 퀴놀론계 항균제에 대한 내성 MRSA 균주의 In Vitro 선발과 그 내성 기전 분석

In Vitro Selection of MRSA Strains Resistance to Some New Fluoroquinolone Antibiotics and Characterization of their Resistance Mechanisms

Clinically isolated methicillin-resistance Staphylococcus aureus strains were exposed to subinhibitory concentration of DW286, DW-224a, gemifloxacin, trovafloxacin, sparfloxacin and ciprofloxacin during 26- to 39-days period. Subculturing led to resistance development, and most of the selected mutants were above susceptible breakpoints. Selected mutants had broad cross resistance to other quinolone antibiotics and only one mutant was completely susceptible to all fluoroquinolones. Twenty five among 42 mutants revealed mutation on DNA gyrase and topoisomerase Ⅳ and action of efflux pumping out system are the resistance mechanism of DW-224a.