双纸片抑制增效试验在AmpC酶检测中应用分析

Application analysis of double-disk synergy test in AmpC β-lactamase detection

目的探讨分析双纸片抑制增效试验在肺炎克雷伯菌产AmpC酶的检测应用,评价该方法在临床实验室的应用价值。方法采用头孢西丁纸片法,头孢西丁三维试验,双纸片抑制增效试验,以及耐药基因多重PCR技术对临床分离菌株进行检测。结果 137株临床分离肺炎克雷伯菌中,对头孢西丁不敏感的菌株共有22株,头孢西丁三维试验阳性有11株;双纸片抑制增效试验FOX/FOX+PBA双纸片组中阳性有18株,CTT/CTT+PBA双纸片组中阳性有11株;多重PCR技术检测阳性有19株。头孢西丁三维试验阳性结果与PCR结果符合率为47.4%(9/19),双纸片抑制增效试验中,CTT/CTT+PBA双纸片组阳性结果与PCR结果符合率为57.9%(11/19);FOX/FOX+PBA双纸片组阳性结果与PCR结果符合率为94.7%(18/19)。结论双纸片抑制增效试验,其方法简便,结果准确性高,其中FOX/FOX+PBA双纸片组可应用于临床分离肺炎克雷伯菌产AmpC酶的检测。

Objective To investigate and analyze the double-disk inhibiting synergy test for detecting AmpC β-lactamase pro-duced by Klebsiella pneumoniae and to evaluate its application value in clinical laboratory.Methods The cefoxitin disk agar diffu-sion method,cefoxitin three-dimensional method,double-disk inhibiting synergy test and drug resistance gene multiplex PCR assay were adopted to detect the clinically isolated bacterial strains.Results Among 137 clinically isolated strains of Klebsiella pneumoni-ae,22 strains were insensitive to cefoxitin and 11 strains were positive by the three-dimensional method;in the double-disk inhibiting synergy test,18 strains were positive for the FOX/FOX＋PBA group and 11 strains were positive for the CTT/CTT＋PBA group respectively;in the multiplex PCR assay,19 strains were positive.The coincidence rate of the cefoxitin three-dimensional method and multiplex PCR methods was 47.4%（9/19）,in the double-disk inhibiting synergy test,the coincidence rate of the positive re-sults in the CTT/CTT＋PBA group and the multiplex PCR methods was 57.9%（11/19）;the coincidence rate of the FOX/FOX＋PBA group and multiplex PCR methods was 94.7%（18/19）.Conclusion The double-disk inhibiting synergy test is simple with highly accurate results,in which the FOX/FOX＋PBA double-disk synergy test could be applied to detect AmpC β-lactamase pro-duced by clinical isolates of Klebsiella pneumoniae.