生物被膜肺炎克雷伯杆菌AmpC酶、超广谱β-内酰胺酶的检测

目的：探讨生物被膜（BF）菌的耐药机制,为临床合理应用抗生素提供理论依据。方法：应用改进的平板培养法建立肺炎克雷伯杆菌BF模型,用银染法和扫描电镜观察鉴定。采用改良三维试验法检测超广谱β-内酰胺酶（ESBLs）及AmpC酶。结果：浮游肺炎克雷伯杆菌单产AmpC酶,单产ESBLs酶及同时产ESBLs和AmpC酶的菌株分别为2.5%（1/40）、20.0%（8/40）、2.5%（1/40）;BF肺炎克雷伯杆菌单产AmpC酶,单产ESBLs及同时产ESBLs和AmpC酶的菌株分别为20.0%（8/40）、45.0%（18/40）、22.5%（9/40）。对浮游组和BF组的检出率两两分别进行χ2检验,BF组各酶的检出率均明显高于普通浮游组各酶的检出率（P〈0.05）。产酶BF肺炎克雷伯杆菌对8种抗生素（除亚胺培南全部敏感外）的耐药率均较高。结论：BF的形成和产生ESBL及AmpC酶的协同作用是肺炎克雷伯杆菌耐药的主要原因之一。

Determination of the AmpC and ESBL produced in the biofilm of klebsiella pneumoniae

AIM： To evaluate the drug-fast mechanism of bacteria growing in biofilm, and to provide the theoretical basis for selecting antimicrobial agents in clinic. METHODS： The model of klebsiella pneu- moniae bacterial biofilm were built up with the modified fiat-board method and identified with the method staining with AgNO3 and confocal scanning laser microscopy. The ESBLs and AmpC were detected by improved three dimensional test. REULTS： The detection rates of AmpC, ESBLs and AmpC plus ESBLs in isolated klebsiella pneumoniae were 2.5% （ 1/40）, 20.0% （8/ 40）and 2.5% （1/40）, whereas the detection rates of AmpC, ESBLs and AmpC plus ESBLs in biofilm klebsiella pneumoniae were 20.0% （8/40）, 45.0% （18/ 40） and 22.5 % （9/40）. The resistance rates of the biofilm klebsieUa pneumoniae producting AmpC and ESBLs to eight kinds of antibiotics were higher. CONCLUSION： The synergetic effect of the formation of biofilm and the production of ESBLs and AmpC is one of the main reasons that klebsiella pneumoniae resists antibiotics.