摘要
目的明确1株福氏志贺菌RJ506对第3代头孢菌素和氟喹诺酮同时耐药的分子机制。方法通过E-test检测RJ506对各抗菌药物的最低抑菌浓度(MIC),接合试验了解耐药性是否由质粒介导;用聚合酶链反应(PCR)分别扩增染色体和质粒介导的喹诺酮耐药基因并进行序列分析,检测染色体介导耐药的突变位点和质粒介导耐药的基因型;用PCR扩增CTX-M各组超广谱β-内酰胺酶(ESBLs)基因并进行序列分析,检测ESBLs的基因型。结果RJ506对头孢噻肟和环丙沙星同时耐药,其染色体DNA旋转酶gyrA亚基的83位发现Ser→Leu突变,而gyrB和parC未见突变;该菌株同时含有ESBLs基因blaCTX-M-3和喹诺酮耐药基因qnrS,且分别位于不同的可接合质粒上。结论本实验在国内的志贺菌中检出质粒介导的喹诺酮耐药基因qnrS和CTX-M-3型ESBLs。
Objective To explore the molecular mechanism of co-resistance to third-generation cephalosporins（cefotaxime and ciprofloxacin） and fluoroquinolones in an isolate of Shigellaflexneri RJ506. Methods The minimal inhi bitory concentrations （MIC） of Shigella flexneri RJ506 were detected by E-test. The resistance to cefotaxime and ciprofloxacin was determined by conjugation. The mutation of chromosome-mediated resistance and the genotype of plasmid-mediated resistance were determined by polymerase chain reaction （PCR） , and chromosome and the resistance gene of plasmid-mediated quinolone were amplified and sequenced. The extended-spectrum β-lactamases （ESBLs） genes and their genotypes were amplified and sequenced by PCR. Results Shigellaflexneri RJS06 was resistant to cefotaxime and ciprofloxacin simultaneously and exhibited the Ser83→Leu mutation in gyrA, but there was no mutation in gyrB and parC. The blacTx-M-3 and qnrS exsisted on two different conjugative plasmids respectively. Conclusions This is a report of a qnrS gene and a blacTx-M-3 gene in an isolate of Shigella flexneri from China.
出处
《检验医学》
CAS
北大核心
2009年第7期489-492,共4页
Laboratory Medicine
基金
上海市南汇区科委课题(NKYL0601)
关键词
福氏志贺菌
超广谱Β-内酰胺酶
质粒
喹诺酮耐药
Shigella flexneri
Extended -spectrum β-lactamase
Plasmid
Quinolone resistance
