嗜麦芽窄食单胞菌L1、L2基因克隆及耐药性转移

Cloning of L1,L2 β-lactamases genes and resistance transfering inStenotrophomonas maltophilia

目的观察临床分离嗜麦芽窄食单胞菌产L1、L2 β内酰胺酶情况,以及是否伴有耐药性转移。方法PCR法扩增、克隆2种β内酰胺酶基因,并行接合转移试验。结果在30株嗜麦芽窄食单胞菌中,L2基因均为阳性;除3株外,27株菌的L1基因为阳性。接合子能够在含氨苄西林、利福平、萘啶酸的麦康凯培养基上生长并传代;而在含利福平、萘啶酸和亚胺培南(美洛培南、头孢他啶、头孢噻肟)的培养基上未见菌落生长。将接合子增菌后,抽提质粒发现12kb的质粒。结论嗜麦芽窄食单胞菌产生2种β内酰胺酶,氨苄西林的耐药性可从供体菌转移到受体菌,同时伴随12kb质粒的移动。

Objective To study the production of L1, 12 β - lactamases, and the transferable resistance in clinical isolates of Stenotrophomonas maltophilia. Methods Two β -lactamases genes were amplified and cloned by PCR method, and conjugation experiment was performed. Restilts L2 gene was detected in all strains, and L1 gene was in 27 isolates except three strains of Stenotrophomonas maltophilia. Conjugons could grow and generate in the media containing ampicillin, rifampicin and nalidixic acid, but could not grow in the media containing rifampicin, nalidixic acid and imipenem （meropenem, ceftazidime, cefotaxime）. At the same time, 12kb plasmid was isolated from conjugons. Conclusion Stenotrophomonas maltophilia produced two β-lactamases. Ampicillin-resistance determinant could transfer from donor strains to recipient strains, accompanied with 12 kb plasmid transmission.