| ObjectiveThe infection caused by multidrug-resistant Pseudomonas aeruginosa(MDR-PA)is a tough issue in current clinical practice.The formation of bacterial biofilms can significantly increase their drug resistance,which is also an important reason for MDR-PA refractory wound infections.This study aims to investigate the in vitro antibacterial effect of resveratrol combined with polymyxin B on MDR-PA and its inhibitory effect on its biofilm.The aim is to clarify the therapeutic effect of resveratrol combined with polymyxin B,in order to provide new strategies and theoretical basis for the treatment of MDR-PA infection.Methods1、From January 2020 to December 2022,30 strains of MDR-PA were collected from Shiyan Renmin Hospital,and the strains were identified by MALDI-TOF mass spectrometer.Use micro broth dilution method to detect the minimum inhibitory concentration(MIC)of polymyxin B on MDR-PA.At the same time,use polymerase chain reaction(PCR)to detect polymyxin B resistance genes in polymyxin B resistant strains.2、Determine the FICI value of the combination of resveratrol and polymyxin B using the chessboard dilution method to determine the interaction between resveratrol and polymyxin B on the strain;Draw a time sterilization curve to observe the synergistic bactericidal ability of resveratrol combined with polymyxin B on MDR-PA.3、Use crystal violet semi quantitative experiment to evaluate the synergistic inhibitory effect of resveratrol combined with polymyxin B on the formation of MDR-PA biofilm;Scanning electron microscope observation of the effect of resveratrol combined with polymyxin B on MDR-PA biofilm.4、Compare the in vitro antibacterial effect of resveratrol combined with polymyxin B on MDR-PA bacteria formed by existing biofilms using bacterial counting method.Results1、25 MDR-PA strains are sensitive to polymyxin B,and 5 strains are resistant to polymyxin B.Pmr AB、Pho PQ and mcr-1 are genes closely related to polymyxin B resistance.Electrophoresis results showed that all five polymyxin B resistant strains had Pmr AB and Pho PQ genes,and no mcr-1 gene was found.The sequencing results showed that all 5 polymyxin B resistant strains exhibited Pmr A mutation(L71R),4 strains exhibited Pmr B mutation(Y345H),and 1 strain also exhibited Pho Q mutation(V260G),with no Pho P mutation detected.2、The results of the chessboard dilution method showed that the FICI value of 25 MDR-PA strains was<0.5,indicating that resveratrol and polymyxin B have synergistic antibacterial effects.The time sterilization curve results indicate that the combination of resveratrol and polymyxin B has synergistic bactericidal activity against MDR-PA.3、Use crystal violet staining to stain the biofilm,the results showed that the OD value of the combination group was significantly lower than that of the single drug group(P<0.01),indicating that the combination of resveratrol and polymyxin B can significantly inhibit the formation of MDR-PA biofilm.The scanning electron microscopy experiment found that the number of bacteria and matrix in the MDRPA biofilm of the combination drug group were significantly lower than those of the resveratrol and polymyxin B single drug group.4、The combination culture of resveratrol and polymyxin B was performed on MDR-PA bacteria with biofilm formation.The bacterial count showed that the combined treatment group had significantly lower bacterial count than the single treatment group(P<0.01),indicating that resveratrol can enhance the in vitro antibacterial effect of polymyxin B on MDR-PA bacteria with biofilm formation.ConclusionsResveratrol not only enhances the bactericidal effect of polymyxin B on MDR-PA,but also enhances the antibacterial activity of polymyxin B against MDR-PA in various ways,such as inhibiting biofilm formation and killing bacteria protected by biofilm.Therefore,resveratrol can be used to improve the clinical efficacy of polymyxin B in treating bacterial infections caused by MDR-PA. |
PDF Full Text Request