产超广谱β-内酰胺酶志贺菌的OXA耐药基因分布与耐药性分析

Genotype distribution of OXA in ESBLs-producing Shigella and analysis of drug resistance

目的了解宁波地区产ESBLs志贺菌中OXA耐药基因携带情况及其基因型,分析其耐药特征,为疾病防控提供依据。方法从监测网络实验室和医院收集志贺菌,菌株分离和鉴定按文献方法;药敏试验采用K-B法;OXA耐药基因检测采用PCR法,阳性产物在Gen Bank上对比确定亚型。结果 93株产ESBLs志贺菌中检出71株OXA耐药基因,检出率为76.34%,阳性产物经测序比对均为OXA-1亚型;带OXA-1基因菌株对青霉素类、四环素类、奎诺酮类抗菌药物有较高的耐药性,对头孢类抗菌药物有一定的耐药性。结论本地区产ESBLs志贺菌携带OXA-1耐药基因率较高,是主要耐药酶流行型,在国内外比较少见。菌株的耐药性较强,B群志贺菌耐抗生素种类和携带耐药基因均高于D群志贺菌,应引起关注。

Objective To understand the genotype distribution of OXA and the drug resistance characteristics in clinical isolates of extended spectrum beta-lactamases（ ESBLs） producing Shigella in Ningbo,so as to provide basis for disease control and prevention. Methods Shigella was collected from the monitoring network laboratories and hospitals; isolation and identification were established by the literature,and the drug susceptibility of Shigella was performed by K-B method. OXA drug resistance gene of Shigella was detected by polymerase chain reaction（ PCR）,and then the PCR positive productions were sequenced and compared in Gen Bank to determine gene subtypes. Results Among 93 ESBLs-producing Shigella,71 strains carried OXA drug resistance gene,the detection rate was 76. 34%,and nucleotide sequence analysis showed that the subtype was OXA-1.These OXA-1 strains showed obvious resistance to penicillins,tetracyclines,quinolones,and a certain resistance to cephalosporins. Conclusion The ESBLs-producing Shigella had high carrier rate of OXA-1 drug resistance gene which was the major popular type of drug resistant enzyme in Ningbo,and it is rare in the domestic and foreign researches. Both types of resistance to antibiotics and carrier rate of drug resistance gene in B group of Shigella were higher than D group of Shigella. Therefore,we should pay attention to the drug resistance of ESBLs-producing Shigella.