摘要
目的 查明肺炎克雷伯菌的耐药情况及其超广谱 β 内酰胺酶 (ESBLs)的分型。 方法 采用琼脂稀释法对 1999年 7～ 12月分离的 80株肺炎克雷伯菌进行药敏试验 ,用美国临床实验室标准化委员会 2 0 0 0年制定的方法测ESBLs ,并对所有ESBLs阳性菌株进行质粒接合试验、等电点 (pI)测定 ,并对其中CK2 3株的ESBLs耐药基因做了序列分析。结果 2 8/80株 (35 % )的肺炎克雷伯菌产ES BLs。该 2 8株中 2 0株临床菌的耐药质粒接合成功。等电聚焦电泳显示 :结合子的粗提酶中 13/2 0(6 5 % )有pI为 8.8的酶 ,10 /2 0 (5 0 % )有pI为 7.6的酶 ,9/2 0 (4 5 % )有pI为 5 .6的酶。 13株有pI值为8.8的ESBLs阳性的肺炎克雷伯菌对头孢噻肟的耐药明显高于头孢他啶 ,从中抽取CK2 3结合子进行耐药基因的PCR扩增和测序 ,证实为CTX M型酶 ,与CTX M 3比较 ,仅有 3个氨基酸序列不同。结论 2 8/80株 (35 % )的肺炎克雷伯菌产ESBLs。 13/2 0 (6 5 % )株肺炎克雷伯菌接合子产pI 8.8的 β 内酰胺酶 ,系CTX M型的ESBLs,它极类似CTX M
Objective To determine the ESBLs of Klebsiella pneumoniae and ESBL typing by molecular genetic procedures. Methods MIC test and ESBLs confirmation test were taken by agar dilution method in 80 strains of Klebsiella pneumoniae isolated in Beijing area from July 1999 to December 1999. To the 20 ESBLs positive conjugates isoelectric focusing was given. And nucleotide sequencing was analysed to conjugate strain CK23. Results 28 (35%) of the 80 strains of Klebsiella pneumoniae produced ESBLs. In the 28 strains, 20 were successfully done with conjugation of resistant plasmid. Isoelectric focusing results revealed that 13 (65%) of the 20 strains produced an ESBLs protein with a pI of 8.8 with or without additional pI 7.6 and pI 5.4. These β lactamases were all inhibited by clavulanite acid. The strains with pI=8.8 protein were highly resistant to cefotaxime and ceftriaxone but were susceptible or intermediate to ceftazidime. We picked CK23 strain out from 13 conjugates for gene cloning by the primers designed for bla CTX M and nucleotide sequencing. The results showed that the ESBLs gene in CK23 was CTX M, highly similar to CTX M 3 but had 3 amino acids, which were Glu39Gly, Leu122Pro, Asp278His. Conclusions 28 (35%) of the 80 strains of Klebsiella pneumoniae produced ESBLs. Resistant plasmid successfully conjugated in 20 of the 28 ESBLs producing strains. 13 of the 20 (65%) conjugates pruduced a pI =8.8 ESBLs,which was CTX M ESBLs,with only 3 amino acids different from CTX M 3. This paper indicated that a type of CTX M ESBLs existed in Klebsiella pneumoniae in Beijing, which specifically confers resistance to cefotaxime.
出处
《中华检验医学杂志》
CAS
CSCD
北大核心
2001年第4期207-210,共4页
Chinese Journal of Laboratory Medicine
