产超广谱β-内酰胺酶大肠埃希菌和肺炎克雷伯菌的检测

【摘要】 目的 选择适用于检测产超广谱β-内酰胺酶(ESBLs)临床大肠埃希菌、肺炎克雷伯耐药菌株的最佳方案。方法 临床分离的110株大肠埃希菌和84株肺炎克雷伯菌经初筛试验，用浓度梯度法（Etest法）、单纸片加抑制剂克拉维酸和单纸片加抑制剂舒巴坦扩散法、阿莫西林及氨苄西林双纸片协同试验，比较5种方法的检出率及其差异。结果 Etest法对产ESBLs大肠埃希菌和肺炎克雷伯菌的检出存在明显的差异（P＜0.01)，肺炎克雷伯菌的检出率(4/20)明显低于大肠埃希菌(16/26)；单纸片扩散法加克拉维酸对两种菌的检出均较高(16/26、12/20)。检测产ESBLs大肠埃希菌时，除氨苄西林双纸片协同法(8/26)检出率低以外，其他4种方法的检出率无明显差异（P＞0.05)，5种方法有较好的一致性。检测产ESBLs肺炎克雷伯菌时，单纸片扩散法加克拉维酸或舒巴坦(12/20)与Etest法、氨苄西林双纸片协同法的检出(4/20)存在差异（P＜0.05)，前两种方法检出率较高。结论 单纸片扩散法应为临床检测ESBLs大肠埃希菌和肺炎克雷伯菌的首选方法。 Detecting extended-spectrum beta-lactamases in Escherichia coli and Klebsiella pneumoniae

KONG Qinglian YU Xiujuan YAO Ping

（Laboratory of Microbiology, First Hospital of Shandong Medical University, Jinan 250012, China）

【Abstract】 Objective To detect ESBLs in E.coli and K.pneumoniae with appropriate method.Methods The suspiciously produced ESBLs were detected by standard screen test among 110 E.coli and 84 K.pneumoniae. ESBLs possessing strains were confirmed by E test, single-disc diffusion test with clavulanic acid or sulbatan, and two kinds of double-disc synergy test. Results There was a significant difference between the detected rate of ESBLs in E.coli (16/26) and K. pneumoniae (4/20) by E test（P＜0.01). The detected rate of K. pneumoniae was lower than that of E.coli. The single-disc diffusion with clavulanic acid showed no difference in the detected rate of ESBLs E.coli (16/26) and K. pneumoniae (12/20). Except one kind of double-disc synergy test (8/26), other methods showed no difference for the detected ESBLs in E.coli（P＞0.05). The single-disc diffusion test with clavulanic acid or sulbatan was applicable to confirm ESBLs in K. pneumoniae (12/20). Conclusions Single-disc diffusion test is a sensitive, convenient and inexpensive method to confirm ESBLs in E.coli and K.pneumoniae in clinical laboratory.

【Key words】 beta-lactamases; Esccherichia coli; Klebsiella pneumoniae

由于β-内酰胺类抗生素的广泛应用及不合理使用，耐药菌株迅速增加。耐药菌株产生的超广谱β-内酰胺酶（ESBLs）能水解几乎所有的β-内酰胺酶类和单酰胺类抗生素，给临床治疗带来极大困难。ESBLs可通过多种形式进行耐药性的扩散^［1］，能造成严重的医院暴发性感染和院外耐药菌株的传播^［2，3］，因此对产ESBLs菌株的检测极为重要。目前临床有多种产ESBLs菌株的检测方法^{［1，4，5］}，对检出率的报道差异很大。为选择适合临床的最为理想的检测方法，我们采用浓度梯度法(Etest法)、两种单纸片扩散法及两种双纸片三底物协同扩散法，对产ESBLs菌株的检测效果进行比较。

一、材料

1.标本来源：分离菌株均来自我院临床送检的血、尿、痰等标本。其中大肠埃希菌110株，肺炎克雷伯菌84株。

2.标准菌株：大肠埃希菌ATCC25922由中国生

表1 26株疑产ESBLs大肠埃希菌确证试验结果