产ESBLs大肠埃希菌的氨基糖苷抗菌药物耐药性及氨基糖苷类钝化酶基因检测

Resistance of ESBLs producing Escherichia coli to aminoglycoside antibiotics and detection of inactive enzyme genes

目的:了解地区产超广谱β-内酰胺酶(ESBLs)大肠埃希菌对氨基糖苷抗生素的耐药情况及氨基糖苷类钝化酶基因分布。方法:采用Kirby-Bauer(K-B)纸片法检测38株产ESBLs大肠埃希菌对庆大霉素、阿米卡星、妥布霉素、奈替米星4种氨基糖苷类抗菌药物的耐药情况;并应用PCR方法检测这38株菌6种氨基糖苷钝化酶基因aac(3)-Ⅰ、aac(3)-Ⅱ、aac(6′)-Ⅱ、aac(6′)-Ib-cr、ant(2″)-Ⅰ、ant(3″)-Ⅰ。结果:38株产ESBLs大肠埃希菌对4种氨基糖苷类抗菌药物的耐药率分别为阿米卡星28.9%,奈替米星39.5%,庆大霉素76.3%,妥布霉素76.3%;aac(3)-Ⅱ、aac(6′)-Ib-cr、ant(3″)-Ⅰ、ant(2″)-Ⅰ阳性率分别为63.2%,36.8%,10.5%,2.6%。未检测出aac(3)-Ⅰ与aac(6′)-Ⅱ基因阳性菌株。结论:产ESBLs大肠埃希菌的氨基糖苷类钝化酶基因以aac(3)-Ⅱ、aac(6′)-Ib-cr基因为主,氨基糖苷类钝化酶基因与氨基糖苷类药物耐药性有一定的联系。临床抗感染过程中应该注重耐药机制的研究。

Objective： To investigate the resistance of extended spectrum β-lactamase （ESBLs） producing Escherichia coli to aminoglycoside antibiotics and genotyping of aminoglycoside inactive enzymes. Methods：Kirby-Bauer（K-B） method was employed to detect the resistance of 38 strains of ESBLs producing Escherichia coli to 4 aminoglycoside antibiotics（ amikacin netihmicin, gentamicin and tobramycin ）. And 6 kinds of aminoglycoside inactive enzymes [saac （ 3 ） - Ⅰ , aac （ 3 ） - Ⅱ , aac （ 6′ ） - Ⅱ, aac （ 6′ ） - Ⅰ b - cr, ant （2＂） - Ⅰ and ant（3＂）- Ⅱ were determined by polymerase chain reaction（PCR）. Results：The resistance rates of the 38 ESBLs producing Escherichia coil to the 4 kinds of aminoglycoside antibiotics were 28.9% ,39.5% ,76.3% and 76.3% respectively;the positive rates of aminoglycoside inactive enzyme genes of aac（ 3 ）- Ⅱ , aac （6′）-Ib- cr, ant （3＂）- Ⅰ and ant （2＂）- Ⅰ were 63.2% ,36.8% , 10.5% and 2.6%, respectively; aac（3 ）- Ⅰ , aac （6′） -Ⅱ were not found in these strains. Conclusions：The aminoglycoside inactive enzyme genes producing Escherichia coil are predominantly aac （ 3 ） - Ⅱ and aac （ 6′ ） -Ib-cr AMEs genes. The aminoglycoside resistance profiles are related to AMEs gene patterns. More attention should be paid to drug resistance mechanism in management of clinical infections.