铜绿假单胞菌和阴沟肠杆菌超超广谱β-内酰胺酶的检测

THE DETECTION OF HYPERPRODUCTION AMPC ENZYME AND EXTENDED-SPECTRUM β-LACTAMASES IN ENTEROBACTER CLOACAE AND PSEUDOMONAS AERUGINOSA

目的 :了解多重耐药的铜绿假单胞菌和阴沟肠杆菌的主要耐药机制超超广谱 β 内酰胺酶即超广谱 β 内酰胺酶 (ESBLs)和高产AmpC酶的产生情况。 方法 :建立一种简易快速地检测超超广谱 β 内酰胺酶的K B药敏试验法 :首先选择 5种药敏纸片 :IMP、FOX、FEP、CTX、CD0 3 ,依据纸片的抑菌环直径综合判断分析。怀疑产AmpC酶的菌株 ,用OB5抑制试验进一步证实。结果 :使用该法分别检测产AmpC酶、ES BLs的 4株标准株和多重耐药的 70株铜绿假单胞菌和 30株阴沟肠杆菌 ,结果各种标准株检测无误。 70株铜绿假单胞菌中产AmpC酶的有 4 0株 ,产ESBLs的有 18株 ,同时产AmpC酶和ESBLs的是 5株 ,还有 9株细菌两类酶检测均阴性 ,原因待分析。同时利用此试验法检测铜绿假单胞菌的诱导阳性率为 4 2 / 70(6 0 % )和阴沟肠杆菌的诱导阳性率为 16 / 30 (5 3 3% )。结论 :此法简易快速 ,能较好地鉴别产ESBLs或和AmpC酶株 ,并适用于临床常规检验。

Objective: To acquire the information about the incidence of ESBLs and/or AmpC enzyme of Enterobacter cloacae (E.cloacae) and Pseudomonas aeruginosa (Ps aeruginosa). Methods: To establish a simple and quick Kirby-Bauer (K-B) test, which can detect AmpC and/or ESBLs. In the test,five disc including IMP, FOX, FEP, CTX, CD_ 03 were selected. First, according to the results of the bacterial susceptibility test, AmpC and/or ESBLs was screened out. If AmpC producing strains were suspected, OB_5 inhibitory test in vitro was followed. Results: We detected 70 isolates of Ps aeruginosa and 30 isolates of E.cloacae and used 4 standard strains producing Ampc or ESBLs as controls. The results showed that all standard strains were detected correctly. Among 70 strains of Ps aeruginosa, 40 were considered as hyperproduction AmpC enzyme strains, 18 strains were ESBLs-producing, 4 strains produced both of them. Among 30 strains of E.cloacae,14 strains produced AmpC, 10 strains produced ESBLs, 5 strains produced both of them. The rest multi-resistant strains were neither AmpC nor ESBLs-producting. Besides, this test can be developed to study induction of inducible β-lactamases (IB) of gram-negative bacteria. 42 of 70 Ps aeruginosa and 16 of 30 E.cloacae could produce inducible β-lactamases Conclusions: The test could be used to detect the hyperproduction of AmpC β-lactamase, or the production of ESBLs, or both of them.