阴沟肠杆菌质粒介导DHA-1型AmpC酶基因的研究

Study on DHA-1 type of AmpC beta-lactamase gene mediated by plasmid in enterobacter cloacae

目的:研究阴沟肠杆菌质粒介导DHA-1型AmpC酶及其基因类型。方法:利用3-氨基苯酚硼酸对AmpC酶的抑制作用检测阴沟肠杆菌的AmpC酶,通过接合实验分析质粒携带ampC基因的转移,用多重PCR及DNA测序技术测定AmpC酶基因,将序列测定结果用EMBOSS软件进行分析。结果:对头孢西丁和头孢噻肟不敏感的59株临床分离的阴沟肠杆菌中,AmpC酶阳性53株,接合实验成功3株,进一步用PCR及DNA测序技术测出此3株阴沟肠杆菌及其接合子细菌的质粒ampC基因类型为DHA-1型。结论:从我院患者送检标本分离的阴沟肠杆菌中检测到AmpC酶,并成功获得3株接合子细菌,从接合子细菌的质粒中检测到DHA-1型ampC基因。

Objective：To study the AmpC beta-lactamase mediated by plasmid in enterobacter cloacae and its genic type. Methods： AmpC beta-lactamase in enterobacter cloacae was detected on the basis that AmpC beta-lactamase could be inhibited by 3-aminophenylboronic acid （APB）. Conjugation test was used to check the transfer of ampC gene mediated by plasmid. Multi- PCR and DNA sequence test was used to detect ampC gene and its genic type. The amplified ampC gene was sequenced and analyzed by EMBOSS software. Results：Among 59 clinical isolates of enterobacter cloacae insusceptible to cefoxitin and cefotaxime, there were 53 strains with positive AmpC beta-lactamase. Among them, 3 transconjugants were obtained by conjugation test. PCR and DNA sequencing were further used to detect the ampC gene type of the three strains and their conjuants, which was analyzed to be DHA-1 type. Conclusion： 3 transconjugants are obtained successfully from AmpC beta-lactamase-producing enterobacter cloacae isolated from patients＇ samples in our hospital, and all of them possess ampC gene of DHA-1 type.