美罗培南对las/rhl基因缺陷型铜绿假单胞菌早期生物膜的作用

Effect of Meropenem on the biofilms of Pseudomonas aeruginosa las/rhl mutantions in vitro

目的研究美罗培南(meropenem,MEM)对铜绿假单胞菌PAO1野生型及其PAO1lasI rhlI、PAO1lasR rhlR基因缺陷型菌株早期生物膜的作用。方法①测定美罗培南对铜绿假单胞菌PAO1野生型及其PAO1lasI rhlI和PAO1lasR 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、PAO1lasI rhlI和PAO1lasR rhlR基因缺陷型体外生物膜培养3d后,用26mg·L-1的美罗培南溶液作用24h,然后用扫描电子显微镜观察生物膜的情况。结果①PAO1野生型,PAO1lasI rhlI基因缺陷型和PAO1lasR rhlR基因缺陷型3种铜绿假单胞菌菌株对MEM的MIC均为1mg·L-1,MBC均为2mg·L-1。②3d后PAO1野生型形成较厚、有孔状通道的生物膜,而lasI rhlI和lasR rhlR基因缺陷型菌株形成结构较简单的薄片状的早期生物膜结构;美罗培南作用后,PAO1野生型的生物膜结构明显稀薄,而PAO1lasI rhlI、PAO1lasR rhlR基因缺陷型的片状生物膜结构基本被破坏,剩下散在的碎片状结构。结论铜绿假单胞菌的las、rhl基因可影响铜绿假单胞菌早期生物膜的形成及其对美罗培南的敏感性。

OBJECTIVE To study the effect of meropenem on the biofilms of P. aeruginosa las/rhl mutation in vitro. METHODS The MIC and MBC of meropenem （MEM） were measured in P. aeruginosa PAO1,lasI rhlI and lasR rhlR mutants. The biofilms of PAO1,lasI rhlI and lasR rhlR mutants were incubated in a polyvinyl chloride tube in 0.9% saline for three days,and then immersed in meropenem solution of 26 mg·L^-1 for 24 hours,followed by examinations of scanning electronic microscopy （SEM）. RESULTS （1） The MIC and MBC of MEM in PAO1,lasI rhlI and lasR rhlR mutants were 1 and 2 mg·L^-1 respectively.（2） After 3 day＇s incubation,PAO1 biofilms showed a well-developed structure. However,the biofilms of lasR rhlR and lasI rhlI mutants were thin and poor developed. After incubation for 24 hours in meropenem solution,PAO1 biofilm became pellicle-shaped,whereas lasR rhlR and lasI rhlI mutants biofilms were almost destructed and there were only small pieces left. CONCLUSION las/rhl genes play probably an important role in the formation of P.aeruginosa biofilm and the resistance to meropenem.