肺炎克雷伯菌AmpC β-内酰胺酶检测及耐药性分析

AmpC β-lactamases of the Klebsiella pneumoniae were detected and their resistance was analyzed

目的对肺炎克雷伯菌持续高产AmpC酶和超广谱β-内酰胺酶（ESBLs）检测及耐药性分析,揭示其耐药机制,指导临床合理用药.方法采用改良酶提取物三维试验法,在常规NCCLS纸片扩散法基础上接种大肠埃希菌ATCC 25922,在头孢西丁和头孢曲松药敏纸片周围放射性切出琼脂小槽,待测菌的酶粗提物在槽内扩散,分别进行AmpC和ESBLs测定.结果121株肺炎克雷伯菌AmpC酶总检出率为2.5%,ESBLs检出率45.5%,AmpC＋ESBLs检出率为0.8%.它们对青霉素类,第1、第2、第3代头孢菌素,头霉素类,单环β-内酰胺类,氟喹诺酮类,磺胺类及一些酶抑制剂复合抗生素耐药率为50%～100%不等.哌拉西林/他唑巴坦耐药率小于50%,未检出亚胺培南的耐药菌株.结论产生ESBLs和Ampc酶是肺炎克雷伯菌对头孢菌素类抗生素耐药的主要机制,ESBLs和AmpC酶的肺炎克雷伯菌对多种抗生素耐药,应加强对β-内酰胺酶的检测和其感染者的治疗.

Objectives The AmpC β-lactamases and extended-spectrum β-lactamases（ESBLs）had been detected in Klebsiella pneumoniae, and their resistance was analyzed. So their main mechanism of resistance was revealed, which will help us medicate reasonably in clinic. Methods Adopting a modified three dimensional extract test,which was used to detect phenotypically isolates which harbor depressed AmpC β-lactamases and production of ESBLs. In the test,the surface of a Mueller - Hinton agar plate was inoculated with E. coli ATCC 25922 as described in NCCLS for disk diffusion method. Results The rate of AmpC β-lactamases was 2.5% and the rate of ESBLs was 45.5% ,and the rate of AmpC ＋ ESBLs was O. 8% in 121 strains of Klbsiella pneumoniae. The resistant rate of penicillins, cephlosporins, cephamycins, monobactams, fluoroquinolones, sulfanilanldes and some β-lactam/β-lactam inhibitor combinations was from 50% - 100%. The resistant rate of PiperaciUin/tazobaetam was less than 50%, and the resistance of imipenam had not been detected. Conclusions ESBLs and AmpC β-lactamases are the most important reistant mechanisms of Klebsiella Pneumoniae to cephalospofins. Producing ESBLs and AmpC β-lactamases Klebsiella pneumonlae were highly resistant to more antibiotics. β-lactamases should be detected timely and treated carefully.