阴沟肠杆菌耐药性与AMEs及BLa基因研究

Investigation into the resistance and genotyping of aminoglycosidemodifying enzyme and βlactamases in Enterobacter cloacae.

目的了解分离的阴沟肠杆菌耐药性及氨基糖苷类修饰酶、β-内酰胺酶相关基因存在状况，给防治提供参考。方法采用MicroScan微生物鉴定系统Neg Combo Panel Type 21阴性复合板微量肉汤法测定临床分离的20株阴沟肠杆菌对抗菌药物的敏感性，采用聚合酶链反应方法分析氨基糖苷类修饰酶及β-内酰胺酶编码基因。结果20株菌均呈严重多重耐药，仅对亚胺培南高度敏感（耐药率5.0％），哌拉西林／他唑巴坦耐药率50．0％，对包括3、4代头孢在内的其他β-内酰胺类及氨基糖苷类抗生素耐药率90．0％～100．0％，对复方新诺明耐药率100％；20株菌均检出氨基糖苷类修饰酶基因，未检出aac（3）-Ⅲ和aac（3）-Ⅳ基因；19株（95．0％）菌检出β-内酰胺酶相关基因，TEM和DHA基因阳性率均为70％，9株菌（45．0％）同时检出TEM和DHA基因，未检出SHV、OXA、PER、VEB和GES基因。结论广州地区医院感染阴沟肠杆菌多重耐药严重，氨基糖苷类修饰酶基因、DHA型质粒AmpC酶基因和TEM型β-内酰胺酶基因携带率高，在介导细菌耐药方面起重要作用。

Objective To investigate the status of drug resistance and genotyping of aminoglycoside - modifying enzymes （AMEs） and β- lactamases（BLs） in Enterobacter cloacae isolated from hospital infections in Guangzhou. Methods Microdilute tests were performed to identify the sensibility of 20 trains of Enterobacter cloacae to 20 bacteriophage by Dade MicroScan system. Genotypes of AMEs and BLs in strains of Enterobacter cloacae were analyzed by PCR. Results The 20 strains were multiresistant to bacteriophage except of IMP. The resistant rates to IMP, P/T and CP were 5.0%, 50.0% and 60.0% respectively. Most of the isolates （90.0% - 100% ） were resistant to aminoglycosides with the resistant rates to other antibiotics of from 90.0% to 100%. The 20 strains（100% ） all carried one or more types of AMEs gene, including ant（3＇ ＇） - Ⅰ （17 trains）, aac（6＇） - Ⅰ （14 trains）, aac （3） - Ⅱ （10 trains）, aac（3） - Ⅰ （6 trains）, aac（6＇） - Ⅱ （6 trains）, aph（3＇） - Ⅵ（2 trains） and ant（2＇ ＇） - Ⅰ （1 trains） . 19 strains（95.0% ） carried the types of BLs gene, including blaTEM （14 trains） and blaDHA （14 trains） . Other 9 trains carried both blarEM and blaDHA. The genes of blasnv, blaOXA, blaPER, blaVER, blaGES, aac（3） - Ⅲ and aac（3） - Ⅳ were not detected in none of the 20 trains of Enterobacter cloacae. Conelusion Enterobacter cloacae isolated from hospital infection were resistannt to multiple drugs. The carrying rates of Enterobacter cloacae with AMEs gene, BLs （blaTEM and blaDHA） were high in Guangzhou, suggesting that it may play a role in mediate the ocurrence of drug resistance in bacterium.