耐喹诺酮的铜绿假单胞菌药物外排泵研究

摘要

Objective This study aims to investigate the efflux system in fluoroquinolone resistance of pseudomonas aerugino⁃sa. Methods MIC values of ciprofloxacin were detected by MH flat containing sub⁃inhibitory concentration (20 mg/L) efflux pump inhibitor carbonyl cyanide chlorophenylhydrazone (carbonyl cyanide 3⁃chlorophenylhydrazone, CCCP) and MH flat without CCCP. Then compare the MIC. Results Efflux pump in 14 strains of pseudomonas aeruginosa was overexpressed, which were mainly mexAB⁃OprM and mexCD⁃OprJ. MIC value of ciprofloxacin decressed 1/2-1/8 times. MexR regulated by mexAB⁃OprM existed V126E muta⁃tion and NfxB regulated by mexCD⁃OprJ existed H109Y mutation. Conclusion The efflux pump is overexpressed in nearly 50% of flu⁃oroquinolone resistant strains of pseudomonas aeruginosa, which is higher than the domestic and foreign reports. The mechanism and drug target change improve the resistance of pseudomonas aeruginosa to fluoroquinolones. The overexpression of efflux pump also en⁃hance the resistance of the bacteria to cefepime and other drugs ( this is not listed) , which need us pay close attention and take meas⁃ures to control this trend.%目的：探讨外排系统在对喹诺酮类药物耐药的铜绿假单胞菌中所起的作用。方法用含亚抑菌浓度（20 mg／L）外排泵抑制剂羰基氰化氯苯腙（carbonyl cyanide 3⁃chlorophenylhydrazone，CCCP）的MH平板和不含泵抑制剂的MH平板分别检测对环丙沙星的MIC值，比较MIC值是否不同；MIC值降低的菌株用RT⁃PCR检测外排泵蛋白基因表达量的变化，用PCR和测序法了解调控外排泵蛋白表达的基因是否存在改变。结果14株铜绿假单胞菌的外排泵存在过度表达，环丙沙星的MIC值降低至原值的1／2～1／8，以mexAB⁃OprM和mexCD⁃OprJ表达增加为主，调控mexAB⁃OprM基因的MexR有V126E突变， mexCD⁃OprJ的调控基因NfxB有H109Y突变。结论外排泵的高表达在喹诺酮耐药的铜绿假单胞菌中存在近50％，高于所见国内外的报道。该机制与药物作用靶位改变共同提高了铜绿假单胞菌对喹诺酮类的耐药，外排泵的高表达同时也提升了该菌对头孢吡肟等其他药物的耐药，是需要密切关注和采取相应措施的流行趋势。