改良的纸片表型筛选法用于AmpC酶的检测

A modified disc method of phenotype screening for detection of AmpC

目的建立并评价一种检测大肠埃希菌和肺炎克雷伯菌产AmpC酶的新方法。方法采用改良的纸片表型筛选法,以头孢西丁三维试验和多重PCR法作为对照,对临床分离的耐第三代头孢菌素的164株大肠埃希菌和40株肺炎克雷伯菌进行AmpC酶的检测。结果164株大肠埃希菌中,改良的纸片表型筛选法检出8株产AmpC酶的阳性菌株(8/164,4.88%),其中有2株同时产ESBLs酶;40株肺炎克雷伯菌中未检出产AmpC酶菌株,但检出2株(2/40,5.00%)诱导产AmpC酶菌株。头孢西丁三维试验在大肠埃希菌中检出AmpC酶阳性菌株8株(8/164,4.88%),在肺炎克雷伯菌中未检出产AmpC酶株。多重PCR法检出大肠埃希菌AmpC酶耐药基因阳性9株(9/164,5.49%),肺炎克雷伯菌阳性2株(2/40,5.00%)。结论改良的纸片表型筛选法可用于检测大肠埃希菌和肺炎克雷伯菌产AmpC酶和诱导产酶株,并可同时检测产ESBLs酶菌株,该法操作简便、结果可靠、无需特殊仪器,可在普通临床实验室应用。

Objective To establish and evaluate a modified disc screening test used for detecting AmpC enzyme in Escherichia coli and Klebsiella pneumoniae. Methods Of 164 strains of clinical isolation of Escherichia eoli and 40 strains of Klebsiella pneumoniae resistant to the third cephalosporin, AmpC enzyme was detected by the modified disc screening test, three-dimensional extract test and multiplex PCR. Results Among the 164 isolates of Escherichia coli,）kmpC enzyme-positive strains were 8,8 and 9 by the above 3 methods, respectively. At the same time,2 ESBLs-positive strains were found by the modified disc screening test in the 8 AmpC-enzyme positive strains. Among the 40 isolates of Klebsiella pneumoniae ,2 strains of induced AmpC were identified by the modified disc screening test and multiplex PCR. Conclusion The modified disc screening test can not only detect AmpC-positive strains, but also the strains with induced AmpC and ESBLs. The modified disc screening test is a simple, rapid and practical method which can be used in clinical laboratories.