铜绿假单胞菌中RND外排泵功能的研究

Screening the RND pumps genes in Pseudomonas aeruginosa

目的铜绿假单胞菌的耐药性与细胞膜的低通透性和膜上存在的RND外排泵有关,而且RND外排泵起主导作用。方法利用发光杆菌的荧光素酶基因操纵子luxCDABE为报道子,对铜绿假单胞菌基因组中所有的12种已知和可能的RND外排泵基因进行了系统的研究。结果低于抑制浓度庆大霉素对PAOC和PAOI有明显的调节作用。低于抑制浓度四环素对PAOJ调节作用,但属于同一类抗生素的土霉素却没有调节作用。α-氨苄青霉素对12个RND外排泵中的11个都有明显的调节。结论这些RND受不同类型抗生素调节并将它们向外排出。外排泵所向外排出的物质如抗生素,在结构上没有可识别的相关性。其中一个由基因PA2520,PA2521和PA2522组成的RND外排泵,不仅能够向外排出锌离子,而且还能向外排出抗生素。

Aim Pseudomoas aeruginosa displays high-level multiple intrinsic resistance, which in part is due to the existence of drug efflux systems in this organisim. The resistance nodulation division （RND） efflux pumps in particular play a major role in resistance to a variety of antimicrobial agents and chemicals in P. aeruginosa. Meth- ods A highthroughput method is established and used to investigate all the RND pump genes under different types of antibiotics and chemicals. Results Gentamycin induced the expression of RND J and I; J was strongly induced in the present of tetracyclin, but not oxytetracycline; the majority of the RND systems was induced by ampicillin. Conclusion The results indicate that the function of the RND pumps efflux does not correlate with the structure or types of the substrates, e.g. antibiotics in a recognizable way. It is also shown that the gene cluster, czcABC, was regulated not only by the metal ion such as zinc, but also by antibiotics.