QSAR Studies on Bacterial Efflux Pump Inhibitors

2015 ◽  
pp. 238-268 ◽  
Author(s):  
Khac-Minh Thai ◽  
Trong-Nhat Do ◽  
Thuy-Viet-Phuong Nguyen ◽  
Duc-Khanh-Tho. Nguyen ◽  
Thanh-Dao Tran
Keyword(s):  
Bacterial Resistance ◽  
Efflux Pump ◽  
Current Knowledge ◽  
Efflux Pumps ◽  
Quantitative Structure Activity Relationship ◽  
Antimicrobial Drug Resistance ◽  
Qsar Studies ◽  
Hospital Stays ◽  
Efflux Pump Inhibitors

Antimicrobial drug resistance occurs when bacteria undergo certain modifications to eliminate the effectiveness of drugs, chemicals, or other agents designed to cure infections. To date, the burden of resistance has remained one of the major clinical concerns as it renders prolonged and complicated treatments, thereby increasing the medical costs with lengthier hospital stays. Of complex causes for bacterial resistance, there has been increasing evidence that proved the significant role of efflux pumps in antibiotic resistance. Coadministration of Efflux Pump Inhibitors (EPIs) with antibiotics has been considered one of the promising ways not only to improve the efficacy but also to extend the clinical utility of existing antibiotics. This chapter begins with outlining current knowledge about bacterial efflux pumps and drug designs applied in identification of their modulating compounds. Following, the chapter addresses and provides a discussion on Quantitative Structure-Activity Relationship (QSAR) analyses in search of novel and potent efflux pump inhibitors.

scholarly journals QSAR Studies on Bacterial Efflux Pump Inhibitors

2017 ◽  
pp. 898-928
Author(s):  
Khac-Minh Thai ◽  
Trong-Nhat Do ◽  
Thuy-Viet-Phuong Nguyen ◽  
Duc-Khanh-Tho. Nguyen ◽  
Thanh-Dao Tran
Keyword(s):  
Bacterial Resistance ◽  
Efflux Pump ◽  
Current Knowledge ◽  
Efflux Pumps ◽  
Quantitative Structure Activity Relationship ◽  
Antimicrobial Drug Resistance ◽  
Qsar Studies ◽  
Hospital Stays ◽  
Efflux Pump Inhibitors

Antimicrobial drug resistance occurs when bacteria undergo certain modifications to eliminate the effectiveness of drugs, chemicals, or other agents designed to cure infections. To date, the burden of resistance has remained one of the major clinical concerns as it renders prolonged and complicated treatments, thereby increasing the medical costs with lengthier hospital stays. Of complex causes for bacterial resistance, there has been increasing evidence that proved the significant role of efflux pumps in antibiotic resistance. Coadministration of Efflux Pump Inhibitors (EPIs) with antibiotics has been considered one of the promising ways not only to improve the efficacy but also to extend the clinical utility of existing antibiotics. This chapter begins with outlining current knowledge about bacterial efflux pumps and drug designs applied in identification of their modulating compounds. Following, the chapter addresses and provides a discussion on Quantitative Structure-Activity Relationship (QSAR) analyses in search of novel and potent efflux pump inhibitors.

scholarly journals Role of efflux pump inhibitor in decreasing antibiotic cross-resistance of Pseudomonas aeruginosa in a burn hospital in Iran

2016 ◽  
Vol 10 (06) ◽  
pp. 600-604 ◽  
Author(s):  
Mahshid Talebi-Taher ◽  
َAli Majidpour ◽  
Abbas Gholami ◽  
Samira Rasouli-Kouhi ◽  
Maryam Adabi
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Cross Resistance ◽  
Beta Lactams ◽  
Efflux Pump Inhibitor ◽  
Efflux Pump Inhibitors

Introduction: Multidrug resistance in Pseudomonas aeruginosa may be due to efflux pump overexpression. This study phenotypically examined the role of efflux pump inhibitors in decreasing antibiotic cross-resistance between beta-lactams, fluoroquinolones, and aminoglycosides in P. aeruginosa isolates from burn patients in Iran. Methodology: A total of 91 phenotypically and genotypically confirmed P. aeruginosa samples were studied. Multidrug cross-resistance was determined using the disk diffusion method and minimum inhibitory concentration (MIC) test. The contribution of efflux pumps was determined by investigating MIC reduction assay to markers of beta-lactams, fluoroquinolones, and aminoglycosides in the absence and presence of an efflux pump inhibitor. All the isolates were also tested by polymerase chain reaction for the presence of mexA, mexC, and mexE efflux genes. Results: Of the isolates, 81 (89%) and 83 (91.2%) were multidrug resistant according to the disk diffusion and MIC method, respectively. Cross-resistance was observed in 67 (73.6%) and 68 (74.7%) of isolates according to the disk diffusion and MIC method, respectively. In the presence of the efflux pump inhibitor, twofold or higher MIC reduction to imipenem, cefepime, ciprofloxacin, and gentamicin was observed in 59, 65, 55, and 60 isolates, respectively. Except for two isolates that were negative for mexC, all isolates were positive for mexA, mexC, and mexE genes simultaneously. Conclusion: Efflux pumps could cause different levels of resistance based on their expression in clinical isolates. Early detection of different efflux pumps in P. aeruginosa could allow the use of other antibiotics and efflux pump inhibitors in combination with antibiotic therapy.

scholarly journals Efflux Pump Mediated Antimicrobial Resistance by Staphylococci in Health-Related Environments: Challenges and the Quest for Inhibition

Antibiotics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1502
Author(s):  
Abolfazl Dashtbani-Roozbehani ◽  
Melissa H. Brown
Keyword(s):  
Antimicrobial Resistance ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Current Knowledge ◽  
Efflux Pumps ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Multidrug Efflux Pump ◽  
New Antibiotics ◽  
Efflux Pump Inhibitors

The increasing emergence of antimicrobial resistance in staphylococcal bacteria is a major health threat worldwide due to significant morbidity and mortality resulting from their associated hospital- or community-acquired infections. Dramatic decrease in the discovery of new antibiotics from the pharmaceutical industry coupled with increased use of sanitisers and disinfectants due to the ongoing COVID-19 pandemic can further aggravate the problem of antimicrobial resistance. Staphylococci utilise multiple mechanisms to circumvent the effects of antimicrobials. One of these resistance mechanisms is the export of antimicrobial agents through the activity of membrane-embedded multidrug efflux pump proteins. The use of efflux pump inhibitors in combination with currently approved antimicrobials is a promising strategy to potentiate their clinical efficacy against resistant strains of staphylococci, and simultaneously reduce the selection of resistant mutants. This review presents an overview of the current knowledge of staphylococcal efflux pumps, discusses their clinical impact, and summarises compounds found in the last decade from plant and synthetic origin that have the potential to be used as adjuvants to antibiotic therapy against multidrug resistant staphylococci. Critically, future high-resolution structures of staphylococcal efflux pumps could aid in design and development of safer, more target-specific and highly potent efflux pump inhibitors to progress into clinical use.

scholarly journals Chalcones Isolated from Arrabidaea brachypoda Flowers as Inhibitors of NorA and MepA Multidrug Efflux Pumps of Staphylococcus aureus

Antibiotics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 351 ◽  
Author(s):  
Luís Mário Rezende-Júnior ◽  
Leila Maria de Sousa Andrade ◽  
Antonio Linkoln Alves Borges Leal ◽  
Avilnete Belem de Souza Mesquita ◽  
Ana Lurdes Portela de Araújo dos Santos ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Binding Sites ◽  
Bacterial Resistance ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Multidrug Resistant ◽  
Public Health Issue ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pumps ◽  
Efflux Pump Inhibitors

Bacterial resistance to antibiotics has become a public health issue around the world. The present study aimed to evaluate the antibacterial activity of chalcones isolated from flowers of Arrabidaea brachypoda, and their potential as efflux pump inhibitors of Staphylococcus aureus efflux pumps. Microdilution assays were performed with natural products from A. brachypoda. Chalcones 1, 3, 4, and 5 did not show intrinsic antimicrobial activity against all S. aureus strains tested, but they were able to potentiate the Norfloxacin action against the SA1199-B (norA) strain, with a better modulating action for the 4 trimethoxylated chalcone. All chalcones were also able to potentiate the action of EtBr against SA1199-B strain, suggesting a potential NorA inhibition. Moreover, chalcone 4 was able to interfere in the activity of MepA, and interfered weakly in the QacA/B activity. Molecular docking analyzes showed that tested chalcones are capable of binding in the hydrophobic cavity of NorA and MepA, in the same Norfloxacin binding site, indicating that chalcone 4 compete with the antibiotic for the same NorA and MepA binding sites. Association of chalcone 4 with Norfloxacin could be an alternative against multidrug resistant S. aureus over-productive of NorA or MepA.

scholarly journals RND Efflux Systems Contribute to Resistance and Virulence of Aliarcobacter butzleri

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 823
Author(s):  
Cristiana Mateus ◽  
Ana Rita Nunes ◽  
Mónica Oleastro ◽  
Fernanda Domingues ◽  
Susana Ferreira
Keyword(s):  
Oxidative Stress ◽  
Human Serum ◽  
Ethidium Bromide ◽  
Biofilm Formation ◽  
Bacterial Resistance ◽  
Efflux Pumps ◽  
Bacterial Virulence ◽  
Relative Fitness ◽  
Mutant Strains

Aliarcobacter butzleri is an emergent enteropathogen that can be found in a range of environments. This bacterium presents a vast repertoire of efflux pumps, such as the ones belonging to the resistance nodulation cell division family, which may be associated with bacterial resistance, as well as virulence. Thus, this work aimed to evaluate the contribution of three RND efflux systems, AreABC, AreDEF and AreGHI, in the resistance and virulence of A. butzleri. Mutant strains were constructed by inactivation of the gene that encodes the inner membrane protein of these systems. The bacterial resistance profile of parental and mutant strains to several antimicrobials was assessed, as was the intracellular accumulation of the ethidium bromide dye. Regarding bacterial virulence, the role of these three efflux pumps on growth, strain fitness, motility, biofilm formation ability, survival in adverse conditions (oxidative stress and bile salts) and human serum and in vitro adhesion and invasion to Caco-2 cells was evaluated. We observed that the mutants from the three efflux pumps were more susceptible to several classes of antimicrobials than the parental strain and presented an increase in the accumulation of ethidium bromide, indicating a potential role of the efflux pumps in the extrusion of antimicrobials. The mutant strains had no bacterial growth defects; nonetheless, they presented a reduction in relative fitness. For the three mutants, an increase in the susceptibility to oxidative stress was observed, while only the mutant for AreGHI efflux pump showed a relevant role in bile stress survival. All the mutant strains showed an impairment in biofilm formation ability, were more susceptible to human serum and were less adherent to intestinal epithelial cells. Overall, the results support the contribution of the efflux pumps AreABC, AreDEF and AreGHI of A. butzleri to antimicrobial resistance, as well as to bacterial virulence.

scholarly journals Microbial Efflux Systems and Inhibitors: Approaches to Drug Discovery and the Challenge of Clinical Implementation

2013 ◽  
Vol 7 (1) ◽  
pp. 34-52 ◽  
Author(s):  
Christina Kourtesi ◽  
Anthony R Ball ◽  
Ying-Ying Huang ◽  
Sanjay M Jachak ◽  
D Mariano A Vera ◽  
...  
Keyword(s):  
Efflux Pump ◽  
Major Theme ◽  
Clinical Implementation ◽  
Multidrug Efflux ◽  
Efflux System ◽  
Development Path ◽  
Microbial Infections ◽  
Efflux Pump Inhibitors ◽  
Shed Light

Conventional antimicrobials are increasingly ineffective due to the emergence of multidrug-resistance among pathogenic microorganisms. The need to overcome these deficiencies has triggered exploration for novel and unconventional approaches to controlling microbial infections. Multidrug efflux systems (MES) have been a profound obstacle in the successful deployment of antimicrobials. The discovery of small molecule efflux system blockers has been an active and rapidly expanding research discipline. A major theme in this platform involves efflux pump inhibitors (EPIs) from natural sources. The discovery methodologies and the available number of natural EPI-chemotypes are increasing. Advances in our understanding of microbial physiology have shed light on a series of pathways and phenotypes where the role of efflux systems is pivotal. Complementing existing antimicrobial discovery platforms such as photodynamic therapy (PDT) with efflux inhibition is a subject under investigation. This core information is a stepping stone in the challenge of highlighting an effective drug development path for EPIs since the puzzle of clinical implementation remains unsolved. This review summarizes advances in the path of EPI discovery, discusses potential avenues of EPI implementation and development, and underlines the need for highly informative and comprehensive translational approaches.

scholarly journals Magnitude of Voriconazole Resistance in Clinical and Environmental Isolates of Aspergillus flavus and Investigation into the Role of Multidrug Efflux Pumps

2018 ◽  
Vol 62 (11) ◽  
Author(s):  
Raees A. Paul ◽  
Shivaprakash M. Rudramurthy ◽  
Manpreet Dhaliwal ◽  
Pankaj Singh ◽  
Anup K. Ghosh ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Azole Resistance ◽  
Wild Type ◽  
Multidrug Efflux ◽  
Environmental Isolates ◽  
Content Type ◽  
Multidrug Efflux Pumps

ABSTRACT The magnitude of azole resistance in Aspergillus flavus and its underlying mechanism is obscure. We evaluated the frequency of azole resistance in a collection of clinical (n = 121) and environmental isolates (n = 68) of A. flavus by the broth microdilution method. Six (5%) clinical isolates displayed voriconazole MIC greater than the epidemiological cutoff value. Two of these isolates with non-wild-type MIC were isolated from same patient and were genetically distinct, which was confirmed by amplified fragment length polymorphism analysis. Mutations associated with azole resistance were not present in the lanosterol 14-α demethylase coding genes (cyp51A, cyp51B, and cyp51C). Basal and voriconazole-induced expression of cyp51A homologs and various efflux pump genes was analyzed in three each of non-wild-type and wild-type isolates. All of the efflux pump genes screened showed low basal expression irrespective of the azole susceptibility of the isolate. However, the non-wild-type isolates demonstrated heterogeneous overexpression of many efflux pumps and the target enzyme coding genes in response to induction with voriconazole (1 μg/ml). The most distinctive observation was approximately 8- to 9-fold voriconazole-induced overexpression of an ortholog of the Candida albicans ATP binding cassette (ABC) multidrug efflux transporter, Cdr1, in two non-wild-type isolates compared to those in the reference strain A. flavus ATCC 204304 and other wild-type strains. Although the dominant marker of azole resistance in A. flavus is still elusive, the current study proposes the possible role of multidrug efflux pumps, especially that of Cdr1B overexpression, in contributing azole resistance in A. flavus.

scholarly journals An alkylaminoquinazoline restores antibiotic activity in Gram-negative resistant isolates

Microbiology ◽  
2011 ◽  
Vol 157 (2) ◽  
pp. 566-571 ◽  
Author(s):  
Abdallah Mahamoud ◽  
Jacqueline Chevalier ◽  
Milad Baitiche ◽  
Elissavet Adam ◽  
Jean-Marie Pagès
Keyword(s):  
Efflux Pump ◽  
Bacterial Species ◽  
Efflux Pumps ◽  
Multidrug Resistant ◽  
Side Chain ◽  
Structural Class ◽  
Gram Negative ◽  
Activity Spectrum ◽  
Efflux Pump Inhibitors ◽  
Drug Efflux Pump

To date, various bacterial drug efflux pump inhibitors (EPIs) have been described. They exhibit variability in their activity spectrum with respect to antibiotic structural class and bacterial species. Among the various 4-alkylaminoquinazoline derivatives synthesized and studied in this work, one molecule, 1167, increased the susceptibility of important human-pathogenic, resistant, Gram-negative bacteria towards different antibiotic classes. This 4-(3-morpholinopropylamino)-quinazoline induced an increase in the activity of chloramphenicol, nalidixic acid, norfloxacin and sparfloxacin, which are substrates of the AcrAB-TolC and MexAB-OprM efflux pumps that act in these multidrug-resistant isolates. In addition, 1167 increased the intracellular concentration of chloramphenicol in efflux pump-overproducing strains. The rate of restoration depended on the structure of the antibiotic, suggesting that different sites in the efflux pumps may be involved. A molecule exhibiting a morpholine functional group and a propyl extension of the side chain was more active.

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