CAJ | 학술논문

目的：了解临床分离的携带blaKPC‐2型碳青霉烯酶基因泛耐药肺炎克雷伯菌对喹诺酮类药物的耐药机制，为临床治疗提供参考依据。方法在2008年11月－2009年7月从住院患者中分离19株携带 blaKPC‐2型碳青霉烯酶基因泛耐药肺炎克雷伯菌，采用聚合酶链反应（PCR）及序列分析的方法分析两种喹诺酮类药物作用靶位编码基因（gyrA、parC）和5种质粒介导的喹诺酮类耐药相关基因。结果19株携带 blaKPC‐2型碳青霉烯酶基因泛耐药肺炎克雷伯菌 gyrA和parC基因PCR扩增均阳性，1株（5．3％）aac（6′）‐Ⅰ b‐cr基因阳性，qnrA、qnrB、qnrS和qepA 基因均阴性；序列分析结果表明，19株 gyrA和parC基因均发生突变，分别导致 gyrA 基因喹诺酮耐药决定区（QRDR）出现两个位点错义突变，导致第83位丝氨酸（Ser）被异亮氨酸（Ile）取代、第87位天冬氨酸（Asp）被甘氨酸（Gly）取代，parC基因QRDR出现1个位点错义突变，导致第80位丝氨酸被异亮氨酸取代。结论染色体介导的耐药机制仍是临床分离的携带 blaKPC‐2型碳青霉烯酶基因泛耐药肺炎克雷伯菌对喹诺酮类药物耐药主要机制。
목적：료해림상분리적휴대blaKPC‐2형탄청매희매기인범내약폐염극뢰백균대규낙동류약물적내약궤제，위림상치료제공삼고의거。방법재2008년11월－2009년7월종주원환자중분리19주휴대 blaKPC‐2형탄청매희매기인범내약폐염극뢰백균，채용취합매련반응（PCR）급서렬분석적방법분석량충규낙동류약물작용파위편마기인（gyrA、parC）화5충질립개도적규낙동류내약상관기인。결과19주휴대 blaKPC‐2형탄청매희매기인범내약폐염극뢰백균 gyrA화parC기인PCR확증균양성，1주（5．3％）aac（6′）‐Ⅰ b‐cr기인양성，qnrA、qnrB、qnrS화qepA 기인균음성；서렬분석결과표명，19주 gyrA화parC기인균발생돌변，분별도치 gyrA 기인규낙동내약결정구（QRDR）출현량개위점착의돌변，도치제83위사안산（Ser）피이량안산（Ile）취대、제87위천동안산（Asp）피감안산（Gly）취대，parC기인QRDR출현1개위점착의돌변，도치제80위사안산피이량안산취대。결론염색체개도적내약궤제잉시림상분리적휴대 blaKPC‐2형탄청매희매기인범내약폐염극뢰백균대규낙동류약물내약주요궤제。
OBJECTIVE To investigate the resistant mechanism of quinolones in clinically isolated pan‐resistant K lebsiella pneumoniae harboring blaKPC‐2 type carbapenemase gene ,so as to provide reference for clincial treat‐ment .METHODS Nineteen strains of pan‐resistant K lebsiella pneumoniae harboring blaKPC‐2 type carbapenemase gene were isolated from the inpatients between Nov .2008 and Jul .2009 .Drug target genes to quinolones (gyrA , parC) and quinolone‐resistance genes mediated by plasmid qnrA ,qnrB ,qnrS ,qepA ,aac(6′)‐Ⅰ b‐cr were ana‐lyzed by PCR and verified by DNA sequencing .RESULTS Of the 19 strains tested ,the positive rate of genes of gyrA ,parC and aac(6′)‐Ⅰ b‐cr were 100 .0% ,100 .0% and 5 .3% (1/19) ,respectively .The rest 4 kinds of genes were all tested negative .Of the 19 strains tested ,the double‐point mutations and amino acid replacements (Ser83→Ile ,Asp87→Gly) were found in quinolone resistance‐determining region (QRDR) of gyrA ,and the sin‐gle‐point mutation and amino acid replacement (Ser80→Ile) were found in QRDR of parC .CONCLUSION Chro‐mosome‐mediated target mutations still play important roles in pan‐resistant K lebsiella pneumoniae harboring blaKPC‐2 type carbapenemase gene resistant to quinolones .