N-乙酰半胱氨酸与环丙沙星联合对铜绿假单胞菌生物被膜的抑制作用

Inhibitory effect of N-acetylcysteine combined with ciprofloxacin on biofilms produced by Pseudomonas aeruginosa

目的研究N-乙酰半胱氨酸(NAC)、环丙沙星(CIP)单用及二者联合对铜绿假单胞菌生物被膜的抑制作用。方法扫描电镜(SEM)观察NAC、CIP单用及二者联合对铜绿假单胞菌PAO1生物被膜形态的影响;结晶紫染色法定量分析二者单用及联合对铜绿假单胞菌生物被膜的影响;噻唑兰法(MTT)法测定二者联用的活菌数。结果 SEM观察到NAC对铜绿假单胞菌PAO1生物被膜有破坏解离作用,与CIP有协同作用;结晶紫染色法定量分析显示铜绿假单胞菌生物被膜的OD值随NAC剂量增大而减小;CIP(8MIC)作用后铜绿假单胞菌生物被膜的OD值下降至对照的69.1%～97.9%;CIP合用0.5、5mg/ml NAC后OD值分别下降至CIP单用的(54.7±7.7)%、(48.9±11.4)%;NAC和CIP单用,分别在2.5mg/ml和2MIC时对成熟被膜下细菌的杀菌作用差异有统计学意义(P<0.01),联合作用后NAC和CIP在0.5mg/ml和1/2MIC时即对被膜下细菌的杀菌作用差异有统计学意义(P<0.01)。结论 NAC对铜绿假单胞菌生物被膜有破坏解离作用、对被膜下细菌有杀菌作用,并与CIP存在一定的协同作用。

OBJECTIVE To investigate the inhibitory effect of N-acetylcysteine（NAC）,ciprofloxacin（CIP） and combination of the two on biofilms produced by Pseudomonas aeruginosa. METHODS The morphology of biofilms after treatment with NAC,CIP and NAC combined with CIP was observed by scanning electron microscope（SEM）.Quantitative analysis of effects of NAC,CIP,NAC＋CIP on performed biofilms of P.aeruginosa were assayed by the optical densities stained by crystal violet.Viable counts of bacteria in biofilms weassayed by the optical densities stained by crystal violet. Viable counts of bacteria in biofilms were determined methylthiazolyldiphenyltetrazolium（MTT） assay. RESULTS When observed by using SEM, NAC detached matu P. aeruginosa biofilms, and was synergistic with eiproiloxacin. Assayed by the optical densities stained wit crystal violet showed P. aeruginosa biofilms reduced when NAC used and proportional to NAC concentrations after treatment with CIP（8MIC）, biofilms reduced to 69.1%- 97.9%0 of the control; after treatment with CI combined with NAC at 0.5 mg/ml and 5mg/ml, biofilms reduced to （54.7±7.7） %, （48.94±11.4%） % of that of CIP treatment alone respectively. NAC and CIP showed significant sterilization of P. aeruginosa in biofilms at2.5 mg/ml and 2MIC, respectively （P〈0.01）. NAC-CIP combinations was synergistic at NAC of 0.5 mg/ml and / CIP at 1/2MIC （P 〈 0. 01）. CONCLUSION NAC has disrupted effect on mature P. aeruginosa biofilms[ / bactericidal effect on biofilm bacteria and synergic effect with CIP.