美罗培南对las、rhl基因缺陷型铜绿假单胞菌生物膜的体外作用

目的:研究美罗培南对铜绿假单胞菌(PA)PAO1野生型及其PAO1 lasI rhlI、PAO1 lasR rhlR基因缺陷型菌株生物膜的作用。方法:(1)试管双倍稀释法测定美罗培南对铜绿假单胞菌PAO1野生型及其PAO1 lasI rhlI和PAO1 lasR rhlR基因缺陷型菌株的最低抑菌浓度(MIC)和最低杀菌浓度(MBC)。(2)采用生理盐水-吸痰管系统进行铜绿假单胞菌PAO1野生型、PAO1 lasI rhlI和PAO1 lasR rhlR基因缺陷型生物膜培养7d后,用美罗培南26 mg·L~(-1)作用24h,然后用扫描电子显微镜观察生物膜的变化。结果:(1)美罗培南对PAO1野生型、PAO1 lasl rhlI基因缺陷型和PAO1 lasR rhlR基因缺陷型3种铜绿假单胞菌菌株的MIC均为1mg·L~(-1),MBC均为2 mg·L~(-1)。(2)7 d后PAO1野生型和PAO1 lasR rhlR基因缺陷型铜绿假单胞菌都可形成较厚、有孔状通道的生物膜,PAO1 lasl rhlI基因缺陷型形成明显稀薄的早期生物膜结构;经过美罗培南作用后,PAO1野生型铜绿假单胞菌的生物膜结构明显稀薄,而PAO1 lasI rhlI、PAO1 IasR rhlR基因缺陷型铜绿假单胞菌的生物膜结构基本被破坏。结论:铜绿假单胞菌的las、rhl基因可影响其生物膜的形成及生物膜对美罗培南的敏感性。

Effects of meropenem on biofilms of Pseudomonas aeruginosa las/rhl mutantions in vitro

AIM:To study the effects of meropenem on the biofilms of Pseuomonas aeruginosa(PA)las/ rhl mutantions in vitro.METHODS:(1)the MIC and MBC of meropenem in PAO1,lasI rhlI,and laiR rhlR mutants were measured.(2)The biofilms of PAO1,lasI rhlI,and lair rhIR mutants were incubated in a polyvinyl chloride tube with 0.9 % saline for 7d,and then immersed in 26 mg·L~(-1)meropenem solution for 24h, followed by examinations of scanning electronic microscopy(SEM).RESULTS:(1)The MIC and MBC of meropenem in PAO1,lasI rhlI and lasR rhIR mutants were 1 mg·L~(-1)and 2 mg.L~(-1)respectively.(2)After 7 d's incubation,PAO1 and lasR rhlR mutant biofilms showed a well-developed structure,however,the biofilm of lasI rhlI mutant was thin and poor;after incubated for 24 h in meropenem solution,PAO1 biofilm become thinner than before,whereas lasR rhlR and lasI rhlI mutants biofilms were almost destructed and there were only small pieces left.CONCLUSION:las/rhl genes could play probably an important role in the formation of Pseuomonas aeruginosa biofilm and the resistance to meropenem.