Effect and mechanism of different concentrationsof resveratrol on hypermucinous Klebsiella pneumoniae
Objective To investigate the effects and mechanisms of resveratrol on in vitro growth and biofilm formation of hypermucinous Klebsiella pneumoniae(HMKP),so as to provide a preliminary theoretical basis for the development of new antimicrobial drugs.Methods Clinical isolates of Klebsiella pneumoniae,non-repetitive,collected from March to October 2023,were identified for species and sensitivity to common antimicrobials using the VITEK-2 compact automatic microbial identification system.The mucous characteristics of the strains were assessed via a string test,and the broth microdilution method determined the minimum inhibitory concentration(MIC)of resveratrol.The effects of different concentrations of resveratrol on the growth of hypermucinous Klebsiella pneumoniae were observed by the bacterial growth curve method,and the effects of different concentrations of resveratrol on HMKP biofilm were determined by the crystal violet staining method.Real-time quantitative reverse transcription PCR(RT-qPCR)was used to detect the expression levels of virulence-related genes(aerobactin,rmpA,and mrkD)in HMKP.Data plotting and analysis were performed using GraphPad Prism 9.0.Results A total of 122 strains of Klebsiella pneumoniae were collected,with 29 strains testing positive in the string test(HMKP).Among these,26 strains were allergic to commonly antimicrobial drugs,such as cephalosporins and their enzyme inhibitors,quinolones,and aminoglycosides,while 3 strains were identified as carbapenem-resistant hypermucinous Klebsiella pneumoniae(HM-CRKP).The minimum inhibitory concentration(MIC)of resveratrol for all HMKP strains exceeded 512 μg/mL.Resveratrol concentrations of 256 μg/mL and 128 μg/mL significantly reduced the growth capacity and biofilm formation capacity of HMKP(P＜0.05)and decreased the expression levels of virulence-related genes rmpA and mrkD.Conclusions Resveratrol can inhibit the growth and biofilm formation of HMKP.The mechanism may be related to the downregulation of virulence-related genes expression,specifically rmpAandmrkD.
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