Background: Although colistin is widely recognized as the last line of antibiotics against gram-negative bacteria, the emergence and spread of colistin resistance severely diminish its clinical efficacy and application. An alternative strategy to alleviate this crisis is to identify promising colistin adjuvants with enhanced antibacterial activity.
Purpose: In this study, the adjuvant effects of paeonol on colistin and the underlying mechanisms were investigated.
Method: Minimum Inhibitory Concentration (MIC) and checkerboard assays were used to investigate the adjuvant activity and structure-activity relationship of paeonol on the antibacterial effect of colistin in vitro. Time-dependent killing and resistance development assays were used to investigate the bactericidal effects and emergence of colistin resistance. Different fluorescent probes and competitive inhibition tests were used to investigate bacterial membrane functions and potential targets. Skin infection and peritonitis-sepsis models were used to evaluate the combined in vivo effects of colistin and paeonol in vivo.
Result: Paeonol enhanced the antibacterial effects of colistin against gram-negative bacteria, particularly Klebsiella pneumoniae. Structure-activity relationship analysis showed that the hydroxyl, 4-methoxy and ketone carbonyl side chains of the benzene ring contributed to the adjuvant effect of paeonol. Paeonol enhances the bactericidal effects of colistin and minimizes the emergence of colistin resistance. Notably, mechanistic studies demonstrated that the combination of colistin and paeonol enhances membrane disruption and oxidative damage, possibly via interactions with phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and cardiolipin (CAL). Importantly, paeonol enhanced the efficacy of colistin in both the skin and peritonitis infection models.
Conclusion: This is the first report on the adjuvant potential of paeonol in colistin to combat K. pneumoniae by promoting membrane disruption and oxidative damage via targeting membrane phospholipids. Notably, the verified target, PE, provides an additional avenue for screening new colistin adjuvants.The combination therapy of paeonol and colistin is a promising strategy for treating infections caused by gram-negative pathogens to address antibiotic resistance issues.
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http://dx.doi.org/10.1016/j.phymed.2024.156061 | DOI Listing |
Front Microbiol
December 2024
Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden.
Lipoproteins are crucial for maintaining the structural integrity of bacterial membranes. In Gram-negative bacteria, the localization of lipoprotein (Lol) system facilitates the transport of these proteins from the inner membrane to the outer membrane. In , an ε-proteobacterium, lipoprotein transport differs significantly from the canonical and well-studied system in , particularly due to the absence of LolB and the use of a LolF homodimer instead of the LolCE heterodimer.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Via Ferrata 5, Pavia, Italy.
The global race against antimicrobial resistance requires novel antimicrobials that are not only effective in killing specific bacteria, but also minimize the emergence of new resistances. Recently, CRISPR/Cas-based antimicrobials were proposed to address killing specificity with encouraging results. However, the emergence of target sequence mutations triggered by Cas-cleavage was identified as an escape strategy, posing the risk of generating new antibiotic-resistance gene (ARG) variants.
View Article and Find Full Text PDFMicrobiol Spectr
December 2024
Division of Infectious Diseases, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Carbapenem-resistant complex (CR-ECC), which is rapidly increasing as the cause of nosocomial infections, has limited treatment options. The aim of this study is to investigate the microbiological and clinical traits and molecular epidemiology of isolates of CR-ECC and provide guidance for antibiotic selection in clinical practice. Clinical CR-ECC isolates (ertapenem MIC ≥ 2 mg/L) were collected from 2021 to 2022.
View Article and Find Full Text PDFJ Postgrad Med
January 2025
Department of Infectious Diseases, Damascus University- Faculty of Medicine, Damascus, Syria.
Introduction: This study aimed to determine the bacterial profile and their antibiotic spectrum in patients with ventilator-associated pneumonia (VAP) and investigate the risk factors for VAP and the presence of multidrug-resistant (MDR) pathogens.
Materials And Methods: A cross-sectional study was included 105 patients with clinically suspected VAP in intensive care units (ICUs) of two university hospitals from Syria, between January 2023 and February 2024. Culture-positive included 69 samples (65.
Infect Dis Clin Microbiol
December 2024
Department of Anesthesiology and Critical Care Unit, Başkent University School of Medicine, Ankara, Türkiye.
Ventriculoperitoneal shunts (VPSs) have been proven to be life-saving procedures, but their complications pose challenges, particularly in this era of rising antibiotic resistance. We report a critically ill case with VPS infection due to colistin-resistant that was treated with intraventricular tigecycline as salvage therapy without adverse events, resulting in microbiologic cure and clinical response. The use of intraventricular tigecycline in the treatment of colistin-resistant appears promising; however, appropriate dosage adjustments and evidence-based recommendations are needed.
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