NalD was reported to be the secondary repressor of the MexAB-OprM multidrug efflux pump, the major system contributing to intrinsic multidrug resistance in Pseudomonas aeruginosa. Here, we show that novobiocin binds directly to NalD, which leads NalD to dissociate from the DNA promoter, and thus de-represses the expression of the MexAB-OprM pump. In addition, we have solved the crystal structure of NalD at a resolution of 2.90 Å. The structural alignment of NalD to its homologue TtgR reveals that the residues N129 and H167 in NalD are involved in its novobiocin-binding ability. We have confirmed the function of these two amino acids by EMSA and plate assay. The results presented here highlight the importance and diversity of regulatory mechanism in bacterial antibiotic resistance, and provide further insight for novel antimicrobial development.
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http://dx.doi.org/10.1111/mmi.13346 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China.
() infections are increasingly challenging due to their propensity to form biofilms and low outer membrane permeability, especially in chronically infected patients with thick mucus. exhibits multiple drug resistance mechanisms, making it one of the most significant global public health threats. In this study, we found that moxifloxacin (MXC) and antibacterial peptides (ε-poly-l-lysine, ε-PLL) exhibited a synergistic effect against multidrug-resistant (MDR-).
View Article and Find Full Text PDFMicrobiol Spectr
January 2025
UMR CNRS 6249 Chrono-Environnement, UFR Santé, Université Bourgogne Franche-Comté, Besançon, France.
Exposure of to cinnamaldehyde (CNA), a natural electrophilic antimicrobial often used as self-medication to treat mild infections, triggers overproduction of the MexAB-OprM efflux system, leading to multidrug resistance. In this study, we demonstrate that CNA exposure induces expression of genes regulated by the two-component system AmgRS. AmgRS activates MexAB-OprM production, independent of repressors MexR and NalD.
View Article and Find Full Text PDFJ Glob Antimicrob Resist
December 2024
Infectious Diseases and Tropical Medicine Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Infectious Diseases, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Research Center for Antibiotic Stewardship and Antimicrobial Resistance, Tehran University of Medical Sciences, Tehran, Iran. Electronic address:
Objectives: Pseudomonas aeruginosa is a major opportunistic pathogen responsible for a wide range of infections. The emergence of antibiotic resistance in this pathogen poses a significant public health challenge. This study aims to conduct a comprehensive meta-analysis of studies conducted in Iran to determine the frequency of key antibiotic resistance mechanisms in Pseudomonas aeruginosa and their association with multidrug-resistant and extensively drug-resistant strains or pandrug-resistant strains.
View Article and Find Full Text PDFAntimicrob Agents Chemother
October 2024
IHMA, Schaumburg, Illinois, USA.
Ceftazidime-avibactam (CZA) and ceftolozane-tazobactam (C/T) are important agents for treating multidrug-resistant infections. In this study, we evaluated the molecular characteristics of 300 globally collected clinical isolates non-susceptible (NS) to CZA, C/T, or both agents. Isolates were CZA-NS and C/T-NS ( = 57), CZA-susceptible (S) and C/T-NS ( = 145), or CZA-NS and C/T-S ( = 98) selected from the Antimicrobial Testing Leadership and Surveillance (ATLAS) surveillance program from 2020 to 2021.
View Article and Find Full Text PDFMicrobiol Res
November 2024
Key Laboratory of Major Diseases in Children, Ministry of Education, National Clinical Research Center for Respiratory Diseases, National Key Discipline of Pediatrics, Laboratory of Infection and Microbiology, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China. Electronic address:
Antimicrobial resistance has been an increasingly serious threat to global public health. The contribution of non-antibiotic pharmaceuticals to the development of antibiotic resistance has been overlooked. Our study found that the anti-inflammatory drug phenylbutazone could protect P.
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