产ESBLs大肠埃希菌、肺炎克雷伯菌的耐药特征和基因分型研究

Identification antibacterial susceptibility and gene typing of extended-spectrum β-lacta-mases producing Escherichia coli and Klebsiella pneumoniae

目的了解广东省中医院产超广谱β-内酰胺酶(ESBLs)的大肠埃希菌、肺炎克雷伯菌的流行、耐药特点和基因型分布。方法对该院2001年7月至2003年8月间临床分离保存的208株大肠埃希菌和肺炎克雷伯菌,用VITEK-32细菌鉴定仪进行细菌鉴定,用K-B法进行药敏试验,用双纸片法进行ESBLs初筛,用NCCLS1999年推荐的确证方法进行ESBLs确证。并采用PCR扩增和PCR产物测序方法对产ESBLs菌株进行基因分型。结果分离到产ESBLs细菌76株,总检出率为36.5%,其中肺炎克雷伯菌阳性率为41.9%(39/93)、大肠埃希菌阳性率为32.2%(37/115),产酶株的耐药率明显高于非产酶株,产ESBLs细菌对青霉素类、环丙沙星及头孢菌素类耐药率较高,加酶抑制剂克拉维酸或他唑巴坦后耐药率有明显下降;PCR初步分型结果表明:TEM型42株(55.3%),均为TEM-1型,CTX-M型27株(35.5%),SHV型33株(43.4%)。结论产ESBLs细菌具有多重耐药的特点;CTX-M型和SHV型是该院产ESBLs大肠埃希菌和肺炎克雷伯菌中流行的基因型。

Objective To investigate the prevalence,phenotypical and genotypical characteristics of extendedspectrum β-lactamases producing in Escherichia coli and Klebsiella pneumoniae in our hospital. Methods The polymerase chain reaction （PCR） was used to establish an effective method for the typing of ESBLs. A total of 208 strains of nonrepetitive E. coli and K. pneumoniae were collected from Juny 2001 to August 2003 in our hospital and investigated for the production for extended-spectrum-lactamases （ESBL）. By phenotypic screening and confirmatory test provided by the National Committee for Clinical labaratory Standards. ESBL genotypes were analyzed by isoelectric point determination. PCR and uncleotide sequencing. Results The ESBL positive rate of E. coli was 32.2%, K. pneumoniae was 41.9% ,TEM were 55.3%. All of them were TEM-1, CTX-M were 35.5% ,SHV were 43. 4%. Conclusions Escherichia coli and Klebsiells pneumoniae produced ESBLs were multi- resistance. This study showed that CTX-M -twe and SHV-type were predominant genotyoes of ESBL in our hospital.