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肠杆菌中喹诺酮类抗菌药耐药大多是由染色体突变引起的,但也可能由含Qnr基因的质粒介导。Qnr蛋白保护DNA不受喹诺酮类药物的影响而降低敏感性,如萘啶酸。Qnr蛋白包括QnrA蛋白、QnrB蛋白和QnrS蛋白,在亚洲广泛存在于被克拉维酸抑制的超广谱β-内酰胺酶和质粒介导的头孢菌素酶的肠杆菌科中,并快速蔓延。QnrA基因包含在su l1型整合子中。近年来,在水生的海藻谢瓦纳拉菌中发现了与QnrA基因起源非常接近的基因,提示液体环境可能决定了QnrA基因在体内的转移场所。进一步分析这种基因转移的作用,可能对阻止这种耐药性在肠杆菌科细菌中的蔓延具有一定指导意义,并可能引出一种新的抗菌药物耐药机制。
Quinolone antibiotic resistance in Enterobacteriaceae is mostly caused by chromosomal mutations, but may also be mediated by plasmids containing the Qnr gene. Qnr protein protects DNA from the effects of quinolones and decreases sensitivity, such as nalidixic acid. Qnr proteins include QnrA protein, QnrB protein and QnrS protein, which are widespread in Asia and rapidly spread in Enterobacteriaceae, an extended spectrum β-lactamase and plasmid-mediated cephalosporins inhibited by clavulanic acid. The QnrA gene is contained in the su l1 integron. In recent years, a gene very similar to the origin of QnrA gene has been found in the aquatic seaweed Shewanella, suggesting that the liquid environment may determine the QnrA gene transfer site in vivo. Further analysis of the role of this gene transfer may prevent the spread of this drug resistance in Enterobacteriaceae has some guidance, and may lead to a new antimicrobial resistance mechanism.