嗜麦芽窄食单胞菌临床分离株的脉冲场凝胶电泳基因分型

Genotyping of clinical Stenotrophomonas maltophilia isolates by pulsed field gel electrophoresis

目的应用脉冲场凝胶电泳技术对嗜麦芽窄食单胞菌（SMA）进行基因分型研究，探讨本菌的医院感染特征。方法对2004—2007年分离的165株SMA进行纸片扩散法药敏试验，用PCR的方法进行耐消毒剂基因的检测，脉冲场凝胶电泳（PF-GE）全DNA指纹图谱技术进行分子分型。结果SMA肺部感染占全部病例的87．9％。对SMA敏感率在80％以上的有米诺环素、左氧氟沙星、复方新诺明；60株SMA耐消毒剂基因的阳性株数为8株（13．3％）；11株SMA进行PFGE同源性分析，结果表明在呼吸ICU和急诊ICU分别有同一克隆株的传播，在呼吸ICU和急诊ICU之间也有同一克隆株的传播。结论SMA是一种重要的医院感染病原菌，由于它的多重耐药性及同克隆株的传播，临床应加强消毒灭菌及患者的隔离。

Objective To identify the genotype of clinical stenotrophomonas maltophilia （SMA） isolates and investigate the characteristics of SMA in nosocomial infections. Methods Totally 165 strains of SMA were clinically isolated during the period of 2004 to 2007. Disc diffusion test （K-B method） was used for antibiotic susceptibility, qacE A 1 gene was detected by polymerase chain reation （PCR）. The gene homology in the SMA strains was analyzed by pulsed field gel electrophoresis （PFGE）. Results Among the tested SMA strains 87.9% sourced from low respiratory tract infection. The antibiotics with more than 80% of sensitive rate against SMA were minocycline,trimethoprim-sulfamethoxazole and levofioxacin. The positive rate of qacEA1 gene was 13.3% in 60 tested strains. The analysis of gene homology for the 11 clinical strains showed that two genotypes from identical clone were found in both respiratory ICU I and emergency ICU respectively. Conclusions SMA was an important pathogenic bacterium in nosocomial infections. The treatment for SMA infection is very difficult since its multi-drug resistance. More attention for effective sterilization and isolation of patients must be paid to prevent the transmission of SMA from same clone.