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目的 研究医院感染肺炎克雷伯菌的β-内酰胺酶基因型.方法 连续收集从临床住院患者中分离的肺炎克雷伯菌,采用接合试验、PCR、PCR产物测序、等电聚焦试验、超广谱β-内酰胺酶(ESBLs)确认试验等方法明确基因型.结果 共收集75株肺炎克雷伯菌,48株(64.0%,48/75)含β-内酰胺酶基因,其中ESBLs占52.0%(39/75).在48株产酶菌株中,携带2种基因型的占35.4%(17/48),携带3种基因型的占14.6%(7/48),携带4种基因型的占10.4%(5/48).CTX-M型β-内酰胺酶基因的检出率最高(30/48,62.5%),其次为TEM型(26/48,54.2%)和SHV型(25/48,52.1%).产DHA-1型AmpC酶的肺炎克雷伯菌有9株,且有8株与ESBLs并存.同时还检测到3株产KPC-2型碳青霉烯酶肺炎克雷伯菌.ESBLs表型确认试验结果的假阴性率为23.1%(9/39).结论 医院感染肺炎克雷伯菌的β-内酰胺基因分布复杂,临床上呈多药耐药状态.

Objective To investigate the genotypes of β-lactamases produced by Klebsiella pneumoniae.Methods Plasmid conjugation,PCR amplification,gene cloning and DNA sequencing,isoelectric focusing electrophoresis and extended-spectrum β-lactamase(ESBLs)confirmatory test were carried out for analyzing the encoding gene of β-lactamases in clinical strains of Klebsiella pneumoniae collected from hospital wards.Results Totally 75 clinical strains of Klebsiella pneumoniae were collected,in which 48 strains were confirmed to produce genotype of β-laetamases(64.0%),including 39 ESBLs-producing Btraim(52.0%).Among 48 strains,17 isolates(35.4%)carried 2 types of ESBLs genes,7(14.6%)carried 3 types of ESBL8 genes,and 5(10.4%)carried 4 types of ESBLs genes.CTX-M was the most comon type(30/48,62.5%),followed by TEM(26/48,54.2%)and SHV(25/48,52.1%).Among 9 isolates with DHA-1 AmpC β-laetamase,8 produced AmpC β-lactamases and ESBLs.Class A carbapenemase KPC-2 was produced in 3 isolates.False negative rate of ESBLs confirmatory test was 23.1%(9/39).Condusion Genotypes of β-lactamases produced by Klebsiella pneumoniae are complicated,which results in multi-drug resistance in clinic.