儿科肺炎克雷伯菌中质粒介导的喹诺酮耐药基因流行现状  

Prevalence of plasmid-mediated quinolone resistance genes in Klebsiella pneumoniae strains in pediat-rics in China

作　　者：薛冠华[1] 李少丽[1] 闫超[1] 冯燕玲[1] 赵汉青[1] 孙红姝[1] 白晓晨 

机构地区：[1]首都儿科研究所细菌研究室,北京100020

出　　处：《中华微生物学和免疫学杂志》2017年第4期303-308,共6页Chinese Journal of Microbiology and Immunology

基　　金：国家自然科学基金（81401678）

摘　　要：目的了解质粒介导的喹诺酮耐药基因（plasmid-mediated quinolone resistance genes，PMQR）在儿科临床分离肺炎克雷伯菌中的流行情况与分布特点。方法收集首都儿科研究所附属儿童医院临床分离的肺炎克雷伯菌，E-test法及琼脂稀释法测定菌株对不同抗生素的最低抑菌浓度（MIC）；PCR法检测质粒介导的喹诺酮耐药基因qnrA、qnrB、qnrS、aac（6’）-I b-cr和qepA；PCR扩增后测序检测超广谱B．内酰胺酶（ESBLs）相关基因及染色体喹诺酮耐药决定基因gyrA及parC的突变情况：质粒接合实验检测耐药基因是否在菌株间转移。结果131株肺炎克雷伯菌中，喹诺酮类药物耐药率为9．92％：PMQR基因检出率为30．5％（40／131），其中90％为产ESBLs菌株，各种基因检出率qn培基因6．87％，qnrS基因22．9％，aac（6’）-Ib-cr基因4．58％，未检出qnrA及qepA基因；40株PMQR阳性菌株中，2株存在gyrA和parC编码氨基酸序列改变；23株PMQR阳性菌株通过接合试验传递成功。相对于受体菌，接合子对环丙沙星的MIC提高了2～32倍。结论质粒介导喹诺酮类药物耐药基因在儿科肺炎克雷伯菌中有高水平的携带率，阳性菌株多为产ESBLs株，耐药基因可在菌株问水平传播。Objective To ＂investigate the prevalence of plasmid-mediated quinolone resistance （ PMQR ） genes among clinical isolates of Klebsiella pneumoniae （ K. pneumoniae ） in pediatrics. Methods A total of 131 non-duplicate clinical isolates of K. pneumoniae were collected in the Mfiliated Children＇s Hospital of Capital Institute of Pediatrics from 2010 to 2012. PMQR genes [ qnrA, qnrB, qnrS, aac（6＇）- I b-cr and qepA ], mutations in the quinolone resistance-determining region （QRDR） and extended spec- trum 13-1actamases （ESBLs） genes in those strains were analyzed by PCR. Minimum inhibitory concentra- tions （MIC） of different antibiotics against those K. pneumoniae strains were determined by broth microdilu- tion method and E-test according to the guidelines issued by the Clinical and Laboratory Standards Institute （CLSI）. Transferability of the PMQR genes was examined by conjugation test with the sodiumazide-resistant Escherichia coli J53. Results Among the 131 isolates, 9.92% were resistant to quinolone and 30.5% were positive for PMQR genes, including 6.87% harboring qnrB gene, 22.9% harboring qnrS gene and 4.58% harboring aac（6＇）- I b-cr gene. Neither qnrA-positive nor qepA-positive strain was detected. Among these PMQR genes-positive isolates, 90% were ESBLs-producing strains and two presented mutations in gyrA and parC genes. Conjugation test showed that these PMQR genes could be transferred horizontally and the cipro- floxaein resistance increased 2 to 32 folds in transconjugants. Conclusion This study indicates that the PMQR gene-carrying rate is high in K. pneumoniae strains isolated in paediatrics in China. Most of the PMQR gene-positive strains are also ESBLs-producing strains. The PMQR genes could be transferred hori- zontally in bacteria.

关 键 词：肺炎克雷伯菌 质粒介导喹诺酮耐药基因 超广谱Β-内酰胺酶 

分 类 号：R446.5[医药卫生—诊断学]