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目的 对我院1株美罗培南耐药(纸片扩散法)的肺炎克雷伯菌进行基因型分析.方法 采用K-B法和微量肉汤稀释法进行耐药表型检测,应用改良Hodge试验和EDTA协同试验检测金属酶.PCR法检测包括碳青每烯酶在内的多种β-内酰胺酶基因、Ⅰ类整合酶、Ⅰ类整合子,并进行测序分析.结果 多重耐药肺炎克雷伯菌除对氨曲南、庆大霉素、妥布霉索、阿米卡星、环丙沙星和左氧氟沙星敏感外,对碳青霉烯类、头孢菌素类、头孢西丁、氨苄西林和复方磺胺甲恶唑均耐药.PCR检测显示该菌株携带IMP型金属β-内酰胺酶基因,DNA测序分析显示扩增出的基因属于IMP-1型,Ⅰ类整合酶、Ⅰ类整合子检测阳性.结论 首次在国内分离到产IMP-1型金属β-内酰胺酶的肺炎克雷伯菌,该酶是引起肺炎克雷伯菌耐碳青霉烯类抗生素的主要原因,并且与Ⅰ类整合子有关.

Objective To study the genes of a carbapenem-resistant Klebsiella pneumoniae strain isolated from a patient. Methods The antibiotic sensitivity test of a multidrug-resistant Klebsiella pneumoniae strain was done according to K-B and MIC method. Metallo-β-lactamase was detected by Modified Hodge Test and EDTA-disk synergy test. Both nine genes encoding β-lactamases, including blaKPC, blaIMP , blaVIM , blaSME , blaCTX-M , blaSHV, blaDHA , blaACT, Class Ⅰ integrase and Class Ⅰ integron were detected by PCR. Positive products were sequenced. Results The Klebsiella pneumoniae was resistant to carbapenems, cephalosporins, cefoxitin, ampicillin and trimethoprim/sulfamethoxazole. Only susceptible to aztreonam, gentamicin, tobramycin, amikacin, ciprofloxacin and levofloxacin. The blaIMP-1 and Class Ⅰ integron were positive. The blaIMP gene was identified by PCR and DNA sequencing confirmed that the gene belong to IMP-1 type Metallo-β-lactamase gene. The strain also carried Class Ⅰ integron and IMP-1 was located in Class Ⅰ integron 5'. Conclusions It is the first detection of IMP-1 Metallo-β-lactamase in Klebsiella pneumoniae. The production of IMP-1 carbapenemase is the main mechanism of carbapenem-resistant in Klebsiella pneumoniae, and multidrug resistance is related to ClassⅠ integron.