临床分离志贺菌中质粒介导磷霉素耐药基因的检测  

Detection plasmid-mediated fosfomycin resistance genes in clinical isolated shigella

作　　者：程跃[1] 梅清[1] 刘艳艳[1] 程君[1] 熊自忠[1] 李家斌[1,2] 

机构地区：[1]安徽医科大学第一附属医院感染病科,合肥230022 [2]安徽省细菌耐药监测中心,合肥230022

出　　处：《安徽医科大学学报》2015年第4期441-445,共5页Acta Universitatis Medicinalis Anhui

基　　金：安徽省教育厅自然科学基金(编号:KJ2011A180);安徽省教育厅自然科学基金(编号:KJ2012A177)

摘　　要：目的在磷霉素耐药志贺菌中检测质粒介导的磷霉素耐药基因fos A、fos A3和fos C2,并分析其传播方式。方法琼脂倍比稀释法测定志贺菌对抗菌药物的最低抑菌浓度(MIC)。在磷霉素耐药菌株中利用聚合酶链式反应(PCR)检测其质粒介导的磷霉素耐药基因fos A、fos A3和fos C2。对阳性扩增产物进行测序分析并对阳性菌株进行接合试验,采用琼脂倍比稀释法测定接合子对12种抗菌药物的MIC值,PCR法检测接合子质粒介导磷霉素耐药基因,肠杆菌科基因间的重复序列PCR(ERIC-PCR)法对阳性菌株进行同源性分析。结果 263株志贺菌中磷霉素耐药25株、中介7株,耐药率为9.5%。PCR结果显示18株磷霉素耐药志贺菌fos A3阳性(基因登录号为KJ716852),阳性率为6.8%,未检出fos A和fos C2。18株fos A3阳性株中,13株结合成功,与受体菌相比,结合子对磷霉素的MIC值明显提高,ERIC-PCR法证实部分fos A3阳性志贺菌具有同源性。结论首次在临床分离的志贺菌中检测到质粒介导的磷霉素耐药基因fos A3,虽然目前检出率不高,但其传播可造成磷霉素耐药性的扩散,需要加强监测。Objective To investigate plasmid-mediated fosfomycin resistance genes fosA,fosA3 and fosC2 in fosfo-mycin resistance shigella and analyze its mode of transmission. Methods Antimicrobial susceptibility testing was performed by agar dilution method. Using polymerase chain reaction（ PCR） to detect the plasmid-mediated fosfomy-cin resistance genes fosA,fosA3 and fosC2 in fosfomycin resistance strains. DNA sequencing of gene-positive strains were analyzed and the conjugation experiment was performed. The minimal inhibitory concentration （ MIC） of recip-ient strains and transconjugants were tested by agar dilution method for fosfomycin and other antimicrobial agents. Plasmid-mediated fosfomycin resistance genes in transconjugants were determined by PCR,enterobacterial intergenic consensus PCR（ ERIC-PCR） was employed to understand the molecular homology of the fosA3-positive isolates. Re-sults In 263 strains of shigella ,resistanc to fosfomycin was 25, intermediate resistance to fosfomycin was 7,resist-ant rate was 9. 5%. PCR results showed that 18 drug-resistant strains fosA3 positive（ GenBank accession numbers of fosA3 is KJ716852）, positive rate was 6. 8%, no fosA and fosC2 gene was detected. The conjugation experiments were successfully carried out in 13 PCR-positive isolates. The MIC of transconjugants against fosfomycin increased differently compared to recipient strains. The homology of partly fosA3-positive isolates was comfirmed by ERIC-PCR. Conclusion The plasmid-mediated fosfomycin resistance gene fosA3 is first detected in clinical isolates of shigella , although the plasmid-mediated fosfomycin resistance genes are lowly prevalent in clinical isolates of shigel-la,but these resistance genes can lead to the characteristic fosfomycin resistence transfer ,which indicates that more attention should be paid to this phenomenon.

关 键 词：志贺菌 磷霉素 质粒 基因 

分 类 号：R378.25[医药卫生—病原生物学]