妇科住院患者分离的大肠埃希菌氟喹诺酮耐药机制与MIC值分布关系的研究

Study on the relationship between the fluoroquinolone resistance mechanism and the MIC value of the Escherichia coli isolated from the gynecological patients

目的探究本院妇科分离大肠埃希菌氟喹诺酮类耐药机制及与MIC值分布相关性。方法收集2010年11月-2014年11月本院妇科分离的452株大肠埃希菌进行鉴定及药敏分析,PCR法扩增DNA解旋酶和拓扑异构酶及质粒介导氟喹诺酮耐药（PMQR）基因。结果筛出氟喹诺酮非敏感菌株143株,占31.6%,除对碳青霉烯类耐药率较低外,对其他药物耐药率为30.07%~95.80%。143株氟喹诺酮类非敏感菌株中主要存在gyr A基因S83L和D87N突变、par C基因S80I和A108V突变,同时还存在qnr A、qnr B、qnr S及acc（6＇）-Ib-cr基因。低MIC耐药因gyr A及par C基因突变所致,而高MIC耐药则因gyr A及par C基因突变与PMQR基因联合携带所致。qnr A主要集中在环丙沙星MIC值为（4~8）μg/ml和〉128μg/ml时;qnr S主要分布在环丙沙星MIC值为（16~64）μg/ml和〉128μg/ml时及左氧氟沙星MIC值为（4~8）μg/ml和〉128μg/ml时。结论本院妇科氟喹诺酮类非敏感大肠埃希菌主要分离自尿液,不同水平MIC耐药机制存在差异,且PMQR基因携带与MIC值分布相关。

Objective To investigate the relationship between the fluoroquinolone resistance mechanism and the MIC value of the Escherichia coli isolated from the gynecological patients. Methods 452 clinical isolates of Escherichia coli isolated from gynecological patients were collected in our hospital from Jan 2011 to Dec 2014,which were isolated and identified routinely. PCR was used to detect the topological isomerase,quinolone resistance determining region and plasmid mediated quinolone resistance（ PMQR） genes. Results 143 fluoroquinolone non susceptible strains were screened out,accounted for 31. 6%,except the resistance rate of carbapenem was lower,other drug resistance rate was 30. 07% to 95. 80%. 143 strains of fluoroquinolone non susceptible strains existed mutations of gyr A gene S83 L and D87 N in,par C gene S80 I and A108 V mutation,there is also a qnr A,qnr B and qnr C and acc（ 6＇）- Ib- cr gene. Low MIC resistance was caused by mutations of gyr A and par C gene,and high MIC resistance caused by gyr A and par C gene mutation and PMQR gene qnr A was mainly concentrated in the MIC value of ciprofloxacin（ 4- 8） μg / ml and 〉128 μg / ml; qnr S was mainly distributed in the MIC value of（ 16- 64） μg / ml, 〉128 μg / ml and the MIC value of ciprofloxacin was（ 4- 8） μg / ml and 〉128 μg / ml. Conclusion In our hospital,the fluoroquinolones non-susceptible E. coli coli mainly isolated from urine,different levels of MIC had different resistance mechanisms,and the MIC value was related to the PMQR genes carrying.