亚抑制浓度的左氧氟沙星对铜绿假单胞菌毒力因子表型及基因表达的影响

Effects of the subinhibitory concentration of levofloxacin promote virulence factor production of Pseudomonas aeruginosa

目的用亚抑制浓度(SIC)抗生素概念评价左氧氟沙星在该浓度下对铜绿假单胞菌毒力因子表型及基因表达的影响。方法用临床标准菌株PAO1,测定在不同浓度下菌株生长曲线,以不影响细菌生长的抗生素浓度为亚抑制浓度。分别测定菌株在SIC的抗生素作用下生物膜形成能力及绿脓杆菌素产生量和鼠李糖脂活性的变化。用实时定量RT-PCR测定菌株毒力蛋白编码基因lasB,rhlA和phzA2基因在SIC浓度的左氧氟沙星作用时表达的变化。结果菌株与SIC浓度的左氧氟沙星共同孵育后,生物膜形成以及绿脓杆菌素产生和鼠李糖脂的活性都较没有抗生素作用时显著增加。lasB、rhlA和phzA2的表达在SIC浓度的左氧氟沙星作用下较无抗生素作用时明显升高。结论亚抑制浓度的左氧氟沙星对铜绿假单胞菌生长没有抑制作用,并可促进其毒力基因的表达,使菌株毒力因子产生增加。

Objective To explore the tion （SIC） of levofloxacin in bacterial effect of subinhibitory coneentra- virulence when it did not inhibit the growth of organism in all stage. Methods Pseudomonas aeruginosa PAO1 was grown in SIC of levofloxacin. The biofilm formation, pyocyanin and rhamnolipid production were determined. The expression of virulence genes, lasB, rhlA and phzA2 at SIC of levofloxacin were detected by real - time quantitative PCR. Results SIC of levofloxacin augmented the bio- film formation, pyocyanin and rhamnolipid production in PAO1. And the virulence factor gene lasB,phzA2 and rhlA are up -regulated in response to subinhibitory levofloxacin. Conclusion SIC of levofloxacin had no in- hibitory effect on PAO1. It induced biofilm formation and the production of virulence factors and their genes expression in PAO1.