肠杆菌科细菌质粒介导喹诺酮耐药基因qnr的研究

目的 调查武汉大学人民医院分离的肠杆菌科细菌中质粒介导喹诺酮类耐药基因qnrA、qnrB、qnrS基因的现状、基因型以及qnr基因阳性菌株所携带的广谱B内酰胺酶基因型.方法 PCR法对179株肠杆菌科细菌(129株大肠埃希菌、37株肺炎克雷伯菌和13株阴沟肠杆菌)进行qnrA、qnrB、qneS基因检测.KB纸片法检测对15种抗菌药的体外抗菌活性.琼脂平皿二倍稀释法检测阳性菌株对环丙沙星的MIC值.质粒接合试验分析qnrA、qnrB、qnrS基因的水平转移能力.对qnr阳性株,检测Ⅰ类整合酶基因及SHV-1、TEM-1、CTX-M、OXA-Ⅰ、OXA-Ⅱ、OXA-Ⅲ、DHA、EBC型β内酰胺酶基因.结果 179株肠杆菌科细菌中,共检测出含qnr基因阳性菌株25株(13.97%),包括6株(3.35%)含有qnrA基因,9株(5.02%)含有qnrB基因,10株(5.59%)含有qnrS基因.阳性株菌均对亚胺培南敏感且对多种抗生素耐药,其中2株qnrA阳性菌株和4株qnrB阳性菌株对喹诺酮类药物敏感.2株qnrA阳性菌株和4株qnrB及qnrS阳性菌株质粒接合成功.23株qnr阳性株Ⅰ类整合酶基因阳性,1株qnrB及qnrS阳性菌株Ⅰ类整合酶基因阴性,14株菌携带TEM-1型广谱β内酰胺酶基因、6株菌携带OXA-Ⅲ型广谱β内酰胺酶基因、7株菌携带EBC型AmpC酶.结论 湖北地区肠杆菌科细菌中存在qnrA、qnrB、qnrS基因的流行,qnr阳性菌株呈多重耐药,且喹诺酮类敏感菌株中有qnr基因的存在.qnr阳性菌株可携带多种广谱p内酰胺酶基因.

The study of plasmid-mediated quionlone resistance gene qnr in Enterobacteriaceae

Objective To explore distribution and genetypes of plasmid-mediated quionlone resistance genes qnrA.qnrB and qnrS in Enterobacteriaceae isolates iu Renmin Hospital of Wuhan University.Methods The qnrA,qnrB and qnrS genes in Enterobaeteriaceae isolates including nonrepetitive 129 isolates of E.coli.13 isolates of E.cloacae and 37 isolates of k pneunoniae were detected by PCR.Antibiotic suseeptibility testing for 15 antibiotics were also performed by K.B in virto.MICs of ciprofloxacin were determined by agar dilution methed.Plasmid conjugatable test wag applied to examine whether qnrA,qnrB and qnrS genes were located in conjugatable plasmid.For qnr-positive strains,integrase I and SHV-1,TEM-1,CTX-M,OXA-I,OXA-Ⅱ,OXA-Ⅲ,DHA and EBC β-lactamases genes were examined.Results 25 qnr-positive isolates were detected among 179 Enterobaeteriaceae isolates,including 6 qnrA-positive isolates,9 qnrB-positive isolates and 10 qnrS-positive isolates,which were presented in 3.35%.5.02%,and 5.59%respectively.All positive isolates were susceptible to imipenem but resistance to some other drugs.2 qnrA-positive isolates and 4 qnrB-positive isolates of them were susceptible to Quinolones.The plasmid wag eonjugatable in 2 qnrA-positive isolates and 4 isolates carrrying qnrB and qnrS.23 qnrA-positive isolates harbored type 1 Integrase,but one isolate with both qnrB and qnrS did not carry Type 1 Integrage.14 isolates of them were TEM-1 producing strains.6 isolates were OXA-Ⅲ-producing strains.and 7 isolates of them were EBC-producing strains.Conciusions In HuBei province,a low prevalence of qnrA,qnrB and qnrS wag determined in Enterebacteriaceae isolates.Muhidrng-resistance was found in qnr-pesitive isolates and qnr genes were detected in quinolone susceptible strains.Extendedspectrum β-lactamages could be presented in qnr-positive isolates too.