临床分离志贺菌质粒介导喹诺酮类耐药基因的检测  

Detection of genotypes of plasmid-mediated quinolone resistance in clinical isolates of Shigella

作　　者：刘艳艳[1] 潘亚超[1] 胡立芬[1] 程君[1] 朱玉林[1] 叶英[2] 李家斌[1] 

机构地区：[1]安徽医科大学第一附属医院感染科,合肥230022 [2]安徽医科大学细菌耐药研究所

出　　处：《中华传染病杂志》2011年第9期524-528,共5页Chinese Journal of Infectious Diseases

基　　金：国家自然科学基金资助项目（30972631）;高校省级自然科学基金重点项目（KJ2010A344）

摘　　要：目的了解临床分离志贺菌质粒介导喹诺酮类耐药基因的种类、分布以及对抗菌药物的耐药性。方法PCR法检测137株志贺菌的qnr、aac（6’）-Ib-cr和qepA基因，对阳性扩增产物进行测序分析并对阳性菌株做接合试验，采用琼脂倍比稀释法测定志贺菌、受体菌和接合子对喹诺酮类及其他抗菌药物的最低抑菌浓度（MIC）。PCR扩增并测序确定接合子的基因型。结果137株志贺菌中，4株菌qnr基因阳性，占2．9％，其中3株携带qnrS2基因，1株携带qnrB4基因（全序列在GenBank的注册号为JF261185、HQ917003）；另外检出5株菌携带aac（6’）-Ib—Cr基因（全序列注册号为JF261186），占3．6％；1株菌携带qepA基因，占0．7％。10株PCR扩增阳性的菌株中有6株转移接合成功。接合子与受体菌相比，对喹诺酮类等抗菌药物的MIC值均有不同程度的提高。结论临床分离志贺菌质粒介导喹诺酮类耐药基因检出率虽较低，但这些耐药基因具有水平转移的特性，应引起高度重视。Objective To investigate the variations and distributions of the plasmid-rnediated quinolone resistance genes in clinical isolates of Shigella and their resistance to antimicrobial agents. Methods qnr, aac（6＇）-Ib-cr and qepA genes were identified hy polymerase chain reaction （PCR） in la7 clinical isolates of Shigella. DNA sequencing of gene-positive strains were analyzed and the conjugation experiment was performed. The minimal inhibitory concentrations （MIC） of Shigella isolates, recipient strains and transconjugants were tested by agar dilution method for quinolones and other antimicrobial agents. The genotype of transconjugants were determined by PCR and sequencing. Results Four （2.9%） strains of the 137 Shigella isolates were qnr gene positive, including 3 qnrS2 positive and 1 qnrB4 positive （GenBank accession numbers of the complete sequence were JF261185 and HQ917003, respectively）. Furthermore, five （3.6%） aac （6＇）-Ib-cr gene-positive strains （GenBank accession number JF261186 ） and one （0.7% ） qepA gene-positive strain were identified in all isolates. The conjugation experiments were successfully carried out in six out of ten PCR-positive isolates. The MIC of transconjugants against quinolones and other antimicrobial agents increased differently compared to recipient strains. Conclusions The plasmid mediated quinolone resistance genes are lowly prevalent in clinical isolates of Shigella. However, these resistance genes have the characteristic of horizontal transfer, which indicates that more attention should be paid to this phenomenon.

关 键 词：志贺菌属 质粒 喹诺酮类 基因 细菌 抗药性 细菌 蛋白质亚型 

分 类 号：R446.5[医药卫生—诊断学]