产质粒介导AmpC酶肺炎克雷白杆菌在下呼吸道感染中的流行研究

The Epidemic Study of Klebsiella Pneumoniae Producing Plasmid-Mediated AmpC β-Lactamase from Lower Respiratory Tract Infection

目的了解下呼吸道感染标本中分离出的产质粒AmpC酶肺炎克雷白杆菌的流行基因型和流行趋势。方法从武汉大学人民医院386例下呼吸道感染患者呼吸道标本中分离出的肺炎克雷白杆菌,对头孢西丁耐药株采用酶提取物改良三维试验筛选高产AmpC酶株,采用聚合酶链反应(PCR)和DNA测序分析质粒介导AmpC酶的流行基因型。结果高产AmpC酶肺炎克雷白杆菌18株(4.7%),主要来源于重症监护病房(ICU),其中呼吸科重症监护病房(RICU)占38.9%。高产AmpC酶肺炎克雷白杆菌中,DHA组12株,EBC组6株。DNA同源性分析显示18株质粒介导AmpC酶肺炎克雷白杆菌分属于15种基因型。结论呼吸道感染的肺炎克雷白杆菌中发现DHA和EBC组质粒AmpC酶,RICU病房有同一克隆株集中分布,提示流行可能。

Objective To explore the prevalent genotypes and molecular mechanisms of isolated Klebsiella pneumoniae producing plasmid-mediated AmpC β-1actamases which causing lower respiratory tract infection. Methods 386 K. pneunoniae isolated in Peopleg Hospital of Wuhan University were verified as positive for AmpC β-laetamases by modified three-dimensional extract test, genotypes for which were determined by PCR and DNA analyzing. The repetitive consensus sequence of Enterobacteriaceae genome PCR （ERIC-PCR） was carried out in order to analyze the homology. Results The ratio of plasmid-mediated AmpC β-1actamases strains was 4. 7%. Among 18 isolates of AmpC β-1actamases producing Klebsiella pneumoniae, with genotypes of DHA （12）, EBC （6）, respectively. 15 types were identified among 18 Klebsiella pneumonlae producing plasmid-mediated AmpC β-lactamases by ERIC-PCR. Conclusion DHA and EBC plasmid-mediated AmpC β- lactamases are found in Klebsiella pneumoniae which causing lower respiratory tract infection in our hospital. Since the same strain is localized in RICU, which suggests it could be epidemic.