【摘要】 目的了解耐头孢西丁革兰阴性杆菌高产AmpC酶发生率及其基因型分布和耐药性状况。方法收集2004年9月-2005年3月分离自南京军区福州总院、福建省立医院、解放军476医院、福州?第二医院住院患者155株耐头孢西丁无重复革兰阴性杆菌,采用酶提取物三维试验检测AmpC酶;API药敏试验板和K-B法测定高产AmpC酶菌株对抗菌药物的敏感性;质粒转化试验定位耐药基因;PCR通用引物扩增AmpC酶与ESBLs基因及其序列测定,确定其基因亚型。结果在155株菌中有36株高产AmpC酶,高产AmpC酶发生率23.2%,分布在13种菌种中,其中大肠埃希菌、肺炎克雷伯菌、鲍氏不动杆菌和阴沟肠杆菌的发生率,分别为29.3%、13.9%、6/10、2/6。在36株高产AmpC酶菌株中检测出DHA-1型2株(肺炎克雷伯菌)、CMY-2型4株(大肠埃希菌),新发现基因CMY-22型1株(大肠埃希菌,GenBank登录号:DQ256079),5株携带CMY基因的大肠埃希菌分别同时带有TEM-1型广谱酶,TEM-144(新发现基因,GenBank登录号:DQ256080)、CTX-M-27、和CTX-M-14超广谱β-内酰胺酶。高产AmpC酶菌株耐药性严重,且呈多重耐药,但对亚胺培南和美罗培南的敏感率>87%。结论耐头孢西丁革兰阴性杆菌高产AmpC酶发生率较高,菌种分布较宽,耐药性强,治疗相关菌造成的感染应以亚胺培南和美罗培南为首选药物。福州地区临床分离株发现产DHA-1型AmpC酶肺炎克雷伯菌、产CMY-2型和CMY-22型AmpC酶大肠埃希菌。CMY-2型和CTX-M-27型为中国大陆首次报告,CMY-22型和TEM-144型为国内外首次发现。更多还原

【Abstract】 In the present study, the incidence rate of the overexpressing AmpC β-lactamases in cefoxitin-resistant Gram-negative bacilli and the status of drug-resistance as well as its genotypes of the plasmid-mediated AmpC β-lactamases were investigated. A total of 155 clinical isolates of the cefoxitin-resistant non-repetitive Gram-negative bacilli collected was subjected to be evaluated by the three-dimensional extract test for AmpC β-lactamases and by the ATB-drug sensitivity test and K-B method for the drug-susceptibility of the over-expressing AmpC β-lactamases. Meanwhile,the plasmid transformation test was used to position the drug-resistant genes and the universal primers were used to amplify the AmpC enzyme and ESBL genes as well as for DNA sequencing in order to determine the genotype of β-lactamases. It was found that 36 strains out of 155 strains of isolates were proved to be the overexpressing AmpC β-lactamses strains of bacteria, with an incidence rate of 23.2%,which were distributed in 13 different species of bacteria. The incidence rates in Escherichia coli, Klebsiella pneumoniae, Acinetobacter bauamnnii and Enterobacter cloacae were 29.3%, 13.9%, 6/10 and 2/6 respectively. In these 36 strains of over-expressing AmpC β-lactamases bacteria,the DHA-1 gene was found in 2 strains of K.pneumoniae,CMY-2 gene in 4 strain of E.coli, CMY-22 gene (newly discovered gene,GenBank accession number: DQ256079) in one train of E.coli. Furthermore,5 strains of E.coli with CMY gene were found to carry the β-lactamases TEM-1,TEM-144 (newly discovered gene,GenBank accession number:DQ256080),CTX-M-27 and CTX-M-14 genes.The degree of resistance of strains with overexpressing AmpC β-lactamses appeared to be serious and usually to be multidrug resistant,but the sensitive rate to imipenem and meropenem was above 87%. It is concluded that the incidence rate of the overexpressing AmpC β-lactamases in cefoxitin-rsistant Gram-negative bacilli is rather high, involving different genera of bacteria,and the degree of drug-resistance is comparatively serious, so that the surveillance to this condition is quite necessary and must be enhanced.更多还原