scholarly journals Inducible, but Not Constitutive, Resistance of Gonococci to Hydrophobic Agents Due to the MtrC-MtrD-MtrE Efflux Pump Requires TonB-ExbB-ExbD Proteins

2002 ◽  
Vol 46 (2) ◽  
pp. 561-565 ◽  
Author(s):  
Corinne Rouquette-Loughlin ◽  
Igor Stojiljkovic ◽  
Tara Hrobowski ◽  
Jacqueline T. Balthazar ◽  
William M. Shafer
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Resistance ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Energy Requirement ◽  
Constitutive Resistance ◽  
Absolute Requirement ◽  
Pump Activity ◽  
Tonb Protein ◽  
Triton X

ABSTRACT The MtrC-MtrD-MtrE efflux pump possessed by Neisseria gonorrhoeae is very similar to the MexA-MexB-OprM efflux pump of Pseudomonas aeruginosa. Because the antimicrobial resistance property afforded by the MexA-MexB-OprM efflux pump also requires the TonB protein, we asked whether a similar requirement exists for the gonococcal efflux pump. Unlike earlier studies with P. aeruginosa, we found that constitutive levels of gonococcal resistance to hydrophobic antimicrobial agents (i.e., Triton X-100 [TX-100]) did not require the TonB, ExbB, or ExbD protein. However, inducible levels of TX-100 resistance in gonococci had an absolute requirement for the TonB-ExbB-ExbD system, suggesting that such resistance in gonococci has an energy requirement above and beyond that required for constitutive pump activity.

scholarly journals Advances in Understanding of the Copper Homeostasis in Pseudomonas aeruginosa

2021 ◽  
Vol 22 (4) ◽  
pp. 2050
Author(s):  
Lukas Hofmann ◽  
Melanie Hirsch ◽  
Sharon Ruthstein
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Copper Homeostasis ◽  
The United States ◽  
World Health ◽  
Cross Resistance ◽  
Metabolism Regulation ◽  
Target Sites

Thirty-five thousand people die as a result of more than 2.8 million antibiotic-resistant infections in the United States of America per year. Pseudomonas aeruginosa (P. aeruginosa) is classified a serious threat, the second-highest threat category of the U.S. Department of Health and Human Services. Among others, the World Health Organization (WHO) encourages the discovery and development of novel antibiotic classes with new targets and mechanisms of action without cross-resistance to existing classes. To find potential new target sites in pathogenic bacteria, such as P. aeruginosa, it is inevitable to fully understand the molecular mechanism of homeostasis, metabolism, regulation, growth, and resistances thereof. P. aeruginosa maintains a sophisticated copper defense cascade comprising three stages, resembling those of public safety organizations. These stages include copper scavenging, first responder, and second responder. Similar mechanisms are found in numerous pathogens. Here we compare the copper-dependent transcription regulators cueR and copRS of Escherichia coli (E. coli) and P. aeruginosa. Further, phylogenetic analysis and structural modelling of mexPQ-opmE reveal that this efflux pump is unlikely to be involved in the copper export of P. aeruginosa. Altogether, we present current understandings of the copper homeostasis in P. aeruginosa and potential new target sites for antimicrobial agents or a combinatorial drug regimen in the fight against multidrug resistant pathogens.

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 Molecular Characteristics and Antimicrobial Susceptibility Profile of Pseudomonas aeruginosa isolated from patients attending Healthcare Facilities in Mthatha, South Africa

2020 ◽  
Author(s):  
Mojisola C. Hosu ◽  
Sandeep D. Vasaikar ◽  
Grace E. Okuthe ◽  
teke apalata
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Antimicrobial Resistance ◽  
Antimicrobial Agents ◽  
Resistance Mechanisms ◽  
High Rate ◽  
Infection Prevention And Control ◽  
Molecular Characteristics ◽  
Mortality And Morbidity ◽  
Resistance Patterns

Abstract Background: Pseudomonas aeruginosa is a common pathogen causing healthcare-associated infections most especially in critically ill and immunocompromised patients. This pathogen poses a public health threat due to its innate resistance to many antimicrobial agents and its ability to acquire new resistance mechanisms under pressure. Infections with Extended spectrum β-lactamases (ESBL)‑producing isolates result into outbreaks that lead to serious antibiotic management concerns with higher mortality and morbidity and significant economic causatives. In this study, we evaluated the antimicrobial resistance patterns and characterized genetically the ESBLs and Metallo- β-lactamases (MBL) produced by this pathogen. Methods: Isolates of P. aeruginosa cultured from patients who attended Nelson Mandela Academic Hospital and other clinics in the four district municipalities of the Eastern Cape between August 2017 and May 2019 were identified; and their antibiotic resistance patterns were tested against amikacin, aztreonam, cefepime, ceftazidime, ciprofloxacin, doripenem, gentamicin, imipenem, levofloxacin, meropenem, piperacillin, piperacillin/tazobactam and tobramycin using the bioMérieux VITEK® 2 and confirmed by Beckman autoSCAN-4 System. Real-time PCR was done using Roche Light Cycler 2.0 to detect the presence of ESBLs; blaSHV, blaTEM and blaCTX-M genes; and MBLs; blaIMP, blaVIM. Results: High antibiotic resistance in decreasing order was observed in piperacillin (64.2%), aztreonam (57.8%), cefepime (51.5%), ceftazidime (51.0%), piperacillin/tazobactam (50.5%), and imipenem (46.6%). A total of 75 (36.8%) multidrug resistant (MDR) isolates were observed of the total pool of isolates. The blaTEM, blaSHV and blaCTX-M was detected in 79.3%, 69.5% and 31.7% isolates (n=82), respectively. The blaIMP was detected in 1.25% while no blaVIM was detected in any of the isolates tested. Conclusions: The study showed a high rate of MDR P. aeruginosa in our setting. The vast majority of these resistant isolates carried blaTEM and blaSHV genes. Continuous monitoring of antimicrobial resistance and strict compliance towards infection prevention and control practices are the best defence against spread of MDR P. aeruginosa.

scholarly journals Efflux Pump-Driven Antibiotic and Biocide Cross-Resistance in Pseudomonas aeruginosa Isolated from Different Ecological Niches: A Case Study in the Development of Multidrug Resistance in Environmental Hotspots

2020 ◽  
Vol 8 (11) ◽  
pp. 1647 ◽  
Author(s):  
Anteneh Amsalu ◽  
Sylvia A. Sapula ◽  
Miguel De Barros Lopes ◽  
Bradley J. Hart ◽  
Anh H. Nguyen ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Multidrug Resistance ◽  
Antimicrobial Resistance ◽  
Molecular Mechanisms ◽  
Efflux Pump ◽  
Principal Component ◽  
Cross Resistance ◽  
Clinical Samples ◽  
Ecological Niches ◽  
Efflux Pump Inhibitor

Pseudomonas aeruginosa is an opportunistic pathogen displaying high intrinsic antimicrobial resistance and the ability to thrive in different ecological environments. In this study, the ability of P. aeruginosa to develop simultaneous resistance to multiple antibiotics and disinfectants in different natural niches were investigated using strains collected from clinical samples, veterinary samples, and wastewater. The correlation between biocide and antimicrobial resistance was determined by employing principal component analysis. Molecular mechanisms linking biocide and antimicrobial resistance were interrogated by determining gene expression using RT-qPCR and identifying a potential genetic determinant for co- and cross-resistance using whole-genome sequencing. A subpopulation of P. aeruginosa isolates belonging to three sequence types was resistant against the common preservative benzalkonium chloride and showed cross-resistance to fluoroquinolones, cephalosporins, aminoglycosides, and multidrug resistance. Of these, the epidemiological high-risk ST235 clone was the most abundant. The overexpression of the MexAB-OprM drug efflux pump resulting from amino acid mutations in regulators MexR, NalC, or NalD was the major contributing factor for cross-resistance that could be reversed by an efflux pump inhibitor. This is the first comparison of antibiotic-biocide cross-resistance in samples isolated from different ecological niches and serves as a confirmation of laboratory-based studies on biocide adapted isolates. The isolates from wastewater had a higher incidence of multidrug resistance and biocide-antibiotic cross-resistance than those from clinical and veterinary settings.

scholarly journals An Update on Antimicrobial Resistance and the Role of Newer Antimicrobial Agents for Pseudomonas aeruginosa

2018 ◽  
Vol 36 (3) ◽  
pp. 303-316 ◽  
Author(s):  
Agila Kumari Pragasam ◽  
Balaji Veeraraghavan ◽  
E. Nalini ◽  
Shalini Anandan ◽  
Keith S. Kaye
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Resistance ◽  
Antimicrobial Agents

scholarly journals Efflux pump inhibitors (EPIs) as new antimicrobial agents against Pseudomonas aeruginosa

2011 ◽  
Vol 6 (1) ◽  
pp. 5870 ◽  
Author(s):  
Momen Askoura ◽  
Walid Mattawa ◽  
Turki Abujamel ◽  
Ibrahim Taher
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Efflux Pump Inhibitors

scholarly journals Regulation of mtrF Expression in Neisseria gonorrhoeae and Its Role in High-Level Antimicrobial Resistance

2005 ◽  
Vol 187 (11) ◽  
pp. 3713-3720 ◽  
Author(s):  
Jason P. Folster ◽  
William M. Shafer
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Sublethal Concentration ◽  
Human Pathogen ◽  
Mucosal Surfaces ◽  
Induction Process ◽  
Inner Membrane Protein ◽  
High Level ◽  
Triton X

ABSTRACT The obligate human pathogen Neisseria gonorrhoeae uses the MtrC-MtrD-MtrE efflux pump to resist structurally diverse hydrophobic antimicrobial agents (HAs), some of which bathe mucosal surfaces that become infected during transmission of gonococci. Constitutive high-level HA resistance occurs by the loss of a repressor (MtrR) that negatively controls transcription of the mtrCDE operon. This high-level HA resistance also requires the product of the mtrF gene, which is located downstream and transcriptionally divergent from mtrCDE. MtrF is a putative inner membrane protein, but its role in HA resistance mediated by the MtrC-MtrD-MtrE efflux pump remains to be determined. High-level HA resistance can also be mediated through an induction process that requires enhanced transcription of mtrCDE when gonococci are grown in the presence of a sublethal concentration of Triton X-100. We now report that inactivation of mtrF results in a significant reduction in the induction of HA resistance and that the expression of mtrF is enhanced when gonococci are grown under inducing conditions. However, no effect was observed on the induction of mtrCDE expression in an MtrF-negative strain. The expression of mtrF was repressed by MtrR, the major repressor of mtrCDE expression. In addition to MtrR, another repressor (MpeR) can downregulate the expression of mtrF. Repression of mtrF by MtrR and MpeR was additive, demonstrating that the repressive effects mediated by these regulators are independent processes.

scholarly journals An H+-Coupled Multidrug Efflux Pump, PmpM, a Member of the MATE Family of Transporters, from Pseudomonas aeruginosa

2004 ◽  
Vol 186 (1) ◽  
pp. 262-265 ◽  
Author(s):  
Gui-Xin He ◽  
Teruo Kuroda ◽  
Takehiko Mima ◽  
Yuji Morita ◽  
Tohru Mizushima ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Host Cells ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
E Coli ◽  
Tetraphenylphosphonium Chloride ◽  
Pcr Method ◽  
Energy Dependent

ABSTRACT We cloned the gene PA1361 (we designated the gene pmpM), which seemed to encode a multidrug efflux pump belonging to the MATE family, of Pseudomonas aeruginosa by the PCR method using the drug-hypersensitive Escherichia coli KAM32 strain as a host. Cells of E. coli possessing the pmpM gene showed elevated resistance to several antimicrobial agents. We observed energy-dependent efflux of ethidium from cells possessing the pmpM gene. We found that PmpM is an H+-drug antiporter, and this finding is the first reported case of an H+-coupled efflux pump in the MATE family. Disruption and reintroduction of the pmpM gene in P. aeruginosa revealed that PmpM is functional and that benzalkonium chloride, fluoroquinolones, ethidium bromide, acriflavine, and tetraphenylphosphonium chloride are substrates for PmpM in this microorganism.

scholarly journals Decreased Azithromycin Susceptibility ofNeisseria gonorrhoeae Due to mtrRMutations

1999 ◽  
Vol 43 (10) ◽  
pp. 2468-2472 ◽  
Author(s):  
Leticia Zarantonelli ◽  
Graciela Borthagaray ◽  
Eun-Hee Lee ◽  
William M. Shafer
Keyword(s):  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Amino Acid Replacement ◽  
Cross Resistance ◽  
Binding Motif ◽  
Coding Region ◽  
Pump System ◽  
Insertional Inactivation ◽  
Ofneisseria Gonorrhoeae ◽  
Triton X

ABSTRACT Single-dose azithromycin therapy has recently been used in Uruguay for the treatment of uncomplicated gonococcal infections. As part of an active surveillance study to monitor the emergence of antibiotic resistance in gonococcal isolates, we examined the levels of azithromycin susceptibility in 51 consecutive isolates obtained from males with uncomplicated gonococcal urethritis. Isolates with decreased susceptibility to azithromycin (MICs, 0.25 to 0.5 μg/ml) were common, and these isolates often displayed cross-resistance to hydrophobic antimicrobial agents (erythromycin and Triton X-100). Resistance to erythromycin and Triton X-100 is frequently due to overexpression of the mtrCDE-encoded efflux pump mediated by mutations in themtrR gene, which encodes a transcriptional repressor that modulates expression of the mtrCDE operon. Accordingly, we questioned whether clinical isolates that express decreased azithromycin susceptibility harbor mtrR mutations. Promoter mutations that would decrease the level of expression ofmtrR as well as a missense mutation at codon 45 in themtrR-coding region that would result in a radical amino acid replacement within the DNA-binding motif of MtrR were found in these strains. When these mutations were transferred into azithromycin-susceptible strain FA19 by transformation, the susceptibility of gonococci to azithromycin was decreased by nearly 10-fold. The mtrCDE-encoded efflux pump system was responsible for this property since insertional inactivation of themtrC gene resulted in enhanced susceptibility of gonococci to azithromycin. We conclude that the mtrCDE-encoded efflux pump can recognize azithromycin and that the emergence of gonococcal strains with decreased susceptibility to azithromycin can, in part, be explained by mtrR mutations.

scholarly journals Characterization of Posttranslationally Modified Multidrug Efflux Pumps Reveals an Unexpected Link between Glycosylation and Antimicrobial Resistance

mBio ◽  
2020 ◽  
Vol 11 (6) ◽  
Author(s):  
Sherif Abouelhadid ◽  
John Raynes ◽  
Tam Bui ◽  
Jon Cuccui ◽  
Brendan W. Wren
Keyword(s):  
Antimicrobial Resistance ◽  
Efflux Pump ◽  
Multidrug Resistant ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Gram Negative ◽  
Content Type ◽  
Multidrug Efflux Pumps ◽  
Pump Activity

ABSTRACT The substantial rise in multidrug-resistant bacterial infections is a current global imperative. Cumulative efforts to characterize antimicrobial resistance in bacteria has demonstrated the spread of six families of multidrug efflux pumps, of which resistance-nodulation-cell division (RND) is the major mechanism of multidrug resistance in Gram-negative bacteria. RND is composed of a tripartite protein assembly and confers resistance to a range of unrelated compounds. In the major enteric pathogen Campylobacter jejuni, the three protein components of RND are posttranslationally modified with N-linked glycans. The direct role of N-linked glycans in C. jejuni and other bacteria has long been elusive. Here, we present the first detailed account of the role of N-linked glycans and the link between N-glycosylation and antimicrobial resistance in C. jejuni. We demonstrate the multifunctional role of N-linked glycans in enhancing protein thermostability, stabilizing protein complexes and the promotion of protein-protein interaction, thus mediating antimicrobial resistance via enhancing multidrug efflux pump activity. This affirms that glycosylation is critical for multidrug efflux pump assembly. We present a generalized strategy that could be used to investigate general glycosylation system in Campylobacter genus and a potential target to develop antimicrobials against multidrug-resistant pathogens. IMPORTANCE Nearly all bacterial species have at least a single glycosylation system, but the direct effects of these posttranslational protein modifications are unresolved. Glycoproteome-wide analysis of several bacterial pathogens has revealed general glycan modifications of virulence factors and protein assemblies. Using Campylobacter jejuni as a model organism, we have studied the role of general N-linked glycans in the multidrug efflux pump commonly found in Gram-negative bacteria. We show, for the first time, the direct link between N-linked glycans and multidrug efflux pump activity. At the protein level, we demonstrate that N-linked glycans play a role in enhancing protein thermostability and mediating the assembly of the multidrug efflux pump to promote antimicrobial resistance, highlighting the importance of this posttranslational modification in bacterial physiology. Similar roles for glycans are expected to be found in other Gram-negative pathogens that possess general protein glycosylation systems.

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