鲍曼不动杆菌SHV型β-内酰胺酶耐药基因分子流行病学研究

目的 分析自临床分离的产SHV型β-内酰胺酶(β-lactamases,BLA)多重耐药鲍曼不动杆菌的SHV型BLA耐药基因序列并确定其所产BLA耐药基因亚型。方法 在2000年7月至2002年12月间从临床分离60株鲍曼不动杆菌,经药敏试验、超广谱β-内酰胺酶(FSBLs)表型确证试验和SHV型BLA耐药基因的聚合酶链反应(PCR)检测,筛选出2株具有多重耐药特性、SHV基因型均阳性的分离株(HZ02、HZ10株),对耐药基因进行序列分析。结果 在2001年6月至2002年1月间分离到的18株(30.0％)鲍曼不动杆菌质粒上携带SNV型BLA耐药基因;NZ02株和NZ10株的SHVPCR扩增阳性,其基因片段分别含825个和833个核苷酸,与Nuesch-lnderbinen等首先发现的SHV-12亚型ESBLs编码基因序列(GenBank注册号:X98105)完全相同。结论 30.0％鲍曼不动杆菌质粒上携带SHV型(超广谱)β-内酰胺酶耐药基因并引起一次医院感染爆发。同时证实在我国浙江省湖州地区临床分离的鲍曼不动杆菌中存在产SHV-12亚型ESBL_s耐药基因菌株。

Study on the molecular epidemiology of SHV type B-lactamase-encoding genes of multiple-drug-resistant acinetobacter baumannii

OBJECTIVE: To analyse the plasmid-mediated SHV type beta-lactamases-encoding genes sequence and to identify its subtype of multiple-drug-resistant acinetobacter baumannii isolated from Huzhou district, Zhejiang province, China. METHODS: Sixty strains of acinetobacter baumannii were isolated from hospitalized patients between Jul, 2000 and Dec, 2002. Susceptibility of antimicrobial agents and confirmatory tests for Extended-spectrum beta-lactamases (ESBLs) were tested by microdilute method. SHV type beta-lactamases-encoding genes were tested by polymerase chain reaction (PCR). SHV sequences of acinetobacter baumannii HZ02 and HZ10 strains were detected by ABI automated sequencer and were analysed to compare with SHV genes that had been published in GenBank. RESULTS: Eighteen (30.0%) strains of acinetobacter baumannii isolated between Jun, 2001 and Jan, 2002 were carrying SHV beta-lactamases resistant gene of plasmids. Detected SHV sequences of acinetobacter baumannii HZ02 strain and HZ10 strain had 825 and 833 nucleotides respectively and had the same gene sequence as the gene encoding SHV-12 subtype of ESBLs discovered in Switzerland. CONCLUSIONS: Thirty percentage of the clinically isolated acinetobacter baumannii were carrying SHV type (extended-spectrum) beta-lactamases resistant gene of plasmids and causing an outbreak in hospital and was discovered to have carried the strains of SHV-12 subtype producing ESBLs gene in acinetobacter baumannii which was the first reported case in the world.