临床分离嗜麦芽寡养单胞菌L1、L2酶基因克隆、测序及定位

Cloning,sequencing and location of genes encoding L1 and L2 β-lactamases in clinical isolates of Stenotrophomonas maltophilia

目的了解临床分离嗜麦芽寡养单胞菌产L 1、L 2β-内酰胺酶情况、酶基因定位及核苷酸序列进化和同源关系。方法PCR法扩增两种β-内酰胺酶基因,通过克隆、测序、序列比对确定其亚型、基因进化、同源关系和基因所在位置。结果细菌染色体DNA和质粒DNA扩增L 1、L 2酶基因阳性,其序列具有明显异质性,两种酶基因位于12kb大小的质粒上。结论嗜麦芽寡养单胞菌绝大多数产生两种β-内酰胺酶,酶基因变异和进化加速的驱动力部分可能与β-内酰胺类抗生素的长期使用有关。

Objectives To investigate the production of L1 and L2 β-lactamases, location and evolution or homology of nucleotide sequences of their encoding genes in clinical isolates of Stenotrophomonas maltophilia. Methods Two β-lactamases-encoding genes were amplified by PCR. The subtypes, evolution or homology and location of genes were determined by gene cloning, sequencing and sequences contrasting. Results L1 and L2 genes in chromosomes and plasmids were amplified, the gene sequences were apparently heterogeneous and the genes were located on 12-kb plasmid. Conclusion Majority of Stenotrophornonas maltophilia isolates produced two β-lactamases. Gene variation and evolution acceleration partly contributed to long-time uses of β- lactams.