肺炎克雷伯菌超广谱β-内酰胺酶基因型研究

目的探讨我院肺炎克雷伯菌中超广谱β-内酰胺酶（ESBLs）基因分布规律。方法对20株经双纸片试验确证为ESBLs表型阳性的肺炎克雷伯菌进行bla TEM-1、blaSHV-1、CTX—M-1组、TOHO-1组等4种基因PCR扩增，并对16株blaSHV-1基因PCR扩增阳性的菌株进行基因序列测定，在Internet网上与GenBank中的已知序列进行核苷酸相似性分析，并进行编码基因对位和氨基酸序列对比分析。结果产ESBLs肺炎克雷伯菌中blaTEM-1，blaSHV-1，CTX—M-1组等3种基因扩增阳性率分别是50．0％、95．0％、20．0％。16株肺炎克雷伯菌中有4株序列与SHV—1a（序列号：X98101，74→934）氨基酸序列完全相同；有3株序列与SHV-2（序列号：AY570959，42→812）100％相同；有2株序列与SHV-11（序列号：AY293069，41→817）100％相同；有4株序列与SHV-27（序列号：AF293345，2→821）氨基酸序列完全相同；有1株序列与SHV-28（序列号：AF538324，12→823）100％相同；有2株序列在GenBank中未找到与之完全相同的序列。结论本地肺炎克雷伯菌中有SHV—1a、SHV-11、SHV-28广谱β-内酰胺酶基因和SHV-2、SHV-27 ESBLs基因存在。

The genotypes of extended-spectrum beta-lactamases in Klebsiella pneumoniae isolates from a hospital in Kunming

Objective To investigate the genotypes of extendedspectrum beta-lactamases(ESBLs)(among) clinical isolates of Klebsiella pneumoniae.Methods Clinical isolates of Klebsiella pneumoniae from a hospital in Kunming were screened for ESBL production by disc diffusion methods as described by the CLSI(formerly NCCLS).ESBL-producing isolates were confirmed by disc diffusion confirming test as recommended by the CLSI(formerly NCCLS).PCR analysis was used for bla_(TEM-1),bla_(SHV-1), CTX-M-1 group and TOHO-1 group genes present in 20 ESBL-producing isolates of Klebsiella pneumoniae.Sequence analysis was performed to identify the bla_(SHV) genes in 16 isolates of Klebsiella pneumoniae.Results The genes of bla_(TEM-1),bla_(SHV-1) and CTX-M-1 group were detected in 50.0%,95.0% and 20.0% of ESBL-producing K.pneumoniae respectively.The ESBL-producing organisms that carried two of these genes was 35.0% of K.pneumoniae.15.0% of the ESBL-producing K.pneumoniae carried all of the three genes.The TOHO-1 group gene was not detected.(Sequence) analysis of ESBL-gene showed that there were bla_(SHV-1a)(n=4),bla_(SHV-11)(n=2),bla_(SHV-28)(n=1),bla_(SHV-2)(n=3) and bla_(SHV-27)(n=4) in 16 isolates of ESBL producing K.pneumoniae.There were two sequences of bla_(SHV-1) gene which was not completely homologous with the genes in GenBank.Conclusion Several bla_(SHV)-genes were detected in clinical isolates of Klebsiella pneumoniae in the hospital in Kunming.