scholarly journals Deciphering the Molecular Recognition Mechanism of Multidrug Resistance Staphylococcus aureus NorA Efflux Pump Using a Supervised Molecular Dynamics Approach

2019 ◽  
Vol 20 (16) ◽  
pp. 4041 ◽  
Author(s):  
Deborah Palazzotti ◽  
Maicol Bissaro ◽  
Giovanni Bolcato ◽  
Andrea Astolfi ◽  
Tommaso Felicetti ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Staphylococcus Aureus ◽  
Efflux Pump ◽  
Structural Information ◽  
Homology Model ◽  
Efflux Pumps ◽  
Critical Conditions ◽  
Resistant Bacteria ◽  
Recognition Mechanism ◽  
Drug Resistant Bacteria

The use and misuse of antibiotics has resulted in critical conditions for drug-resistant bacteria emergency, accelerating the development of antimicrobial resistance (AMR). In this context, the co-administration of an antibiotic with a compound able to restore sufficient antibacterial activity may be a successful strategy. In particular, the identification of efflux pump inhibitors (EPIs) holds promise for new antibiotic resistance breakers (ARBs). Indeed, bacterial efflux pumps have a key role in AMR development; for instance, NorA efflux pump contributes to Staphylococcus aureus (S. aureus) resistance against fluoroquinolone antibiotics (e.g., ciprofloxacin) by promoting their active extrusion from the cells. Even though NorA efflux pump is known to be a potential target for EPIs development, the absence of structural information about this protein and the little knowledge available on its mechanism of action have strongly hampered rational drug discovery efforts in this area. In the present work, we investigated at the molecular level the substrate recognition pathway of NorA through a Supervised Molecular Dynamics (SuMD) approach, using a NorA homology model. Specific amino acids were identified as playing a key role in the efflux pump-mediated extrusion of its substrate, paving the way for a deeper understanding of both the mechanisms of action and the inhibition of such efflux pumps.

scholarly journals 1,2,4-Oxadiazole/2-Imidazoline Hybrids: Multi-target-directed Compounds for the Treatment of Infectious Diseases and Cancer

2019 ◽  
Vol 20 (7) ◽  
pp. 1699 ◽  
Author(s):  
Anton Shetnev ◽  
Sergey Baykov ◽  
Stanislav Kalinin ◽  
Alexandra Belova ◽  
Vladimir Sharoyko ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Efflux Pump ◽  
Ductal Adenocarcinoma ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Gram Negative ◽  
Drug Resistant Bacteria ◽  
Efflux Pump Inhibitors

Replacement of amide moiety with the 1,2,4-oxadiazole core in the scaffold of recently reported efflux pump inhibitors afforded a novel series of oxadiazole/2-imidazoline hybrids. The latter compounds exhibited promising antibacterial activity on both Gram-positive (Staphylococcus aureus, Bacillus subtilis) and Gram-negative (Escherichia coli, Pseudomonas fluorescens) strains. Furthermore, selected compounds markedly inhibited the growth of certain drug-resistant bacteria. Additionally, the study revealed the antiproliferative activity of several antibacterial frontrunners against pancreas ductal adenocarcinoma (PANC-1) cell line, as well as their type-selective monoamine oxidase (MAO) inhibitory profile.

scholarly journals Burkholderia collagen-like protein 8, Bucl8, is a unique outer membrane component of a tetrapartite efflux pump in Burkholderia pseudomallei and Burkholderia mallei

2020 ◽  
Author(s):  
Megan E Grund ◽  
Soo J Choi ◽  
Dudley H McNitt ◽  
Mariette Barbier ◽  
Gangqing Hu ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Burkholderia Pseudomallei ◽  
Triple Helix ◽  
Efflux Pump ◽  
Fusaric Acid ◽  
Efflux Pumps ◽  
Resistant Bacteria ◽  
Burkholderia Mallei ◽  
Membrane Component ◽  
Collagen Triple Helix

AbstractBacterial efflux pumps are an important pathogenicity trait because they extrude a variety of xenobiotics. Our laboratory previously identified in silico Burkholderia collagen-like protein 8 (Bucl8) in the Tier one select agents Burkholderia pseudomallei and Burkholderia mallei. We hypothesize that Bucl8, which contains two predicted tandem outer membrane efflux pump domains, is a component of a putative efflux pump. Unique to Bucl8, as compared to other outer membrane proteins, is the presence of an extended extracellular region containing a collagen-like (CL) domain and a non-collagenous C-terminus (Ct). Molecular modeling and circular dichroism spectroscopy with a recombinant protein, corresponding to this extracellular CL-Ct portion of Bucl8, demonstrated that it adopts a collagen triple helix, whereas functional assays screening for Bucl8 ligands identified binding to fibrinogen. Bioinformatic analysis of the bucl8 gene locus revealed it resembles a classical efflux-pump operon. The bucl8 gene is co-localized with downstream fusCDE genes encoding fusaric acid (FA) resistance, and with an upstream gene, designated as fusR, encoding a LysR-type transcriptional regulator. Using RT-qPCR, we defined the boundaries and transcriptional organization of the fusR-bucl8-fusCDE operon. We found exogenous FA induced bucl8 transcription over 80-fold in B. pseudomallei, while deletion of the entire bucl8 locus decreased the MIC of FA 4-fold in its isogenic mutant. We furthermore showed that the Bucl8 pump expressed in the heterologous Escherichia coli host confers FA resistance. On the contrary, the Bucl8 pump did not confer resistance to a panel of clinically-relevant antimicrobials in Burkholderia and E. coli. We finally demonstrated that deletion of the bucl8-locus drastically affects the growth of the mutant in L-broth. We determined that Bucl8 is a component of a novel tetrapartite efflux pump, which confers FA resistance, fibrinogen binding, and optimal growth.Author SummaryBurkholderia pseudomallei and Burkholderia mallei are highly infectious and multidrug resistant bacteria that are classified by the National Institute of Allergy and Infectious Diseases as Tier one select agents partly due to the intrinsic multidrug resistance associated with expression of the efflux pumps. To date, only few efflux pumps predicted in Burkholderia spp. have been studied in detail. In the current study we introduce Bucl8, an outer membrane component of an unreported putative efflux pump with a unique extended extracellular portion that forms a collagen triple helix and binds fibrinogen. We demonstrate Bucl8’s role in fusaric acid resistance by defining its operon via bioinformatic and transcriptional analyses, as well as by employing loss-of-function and gain-of-function genetic approaches. Our studies also implicate the Bucl8-associated pump in metabolic and physiologic homeostasis. Understanding how Bucl8 efflux pump contributes to Burkholderia pathology will foster development of pump inhibitors targeting transport mechanism or identifying potential surface-exposed vaccine targets.

scholarly journals Systematic Analysis of Efflux Pump-Mediated Antiseptic Resistance in Staphylococcus aureus Suggests a Need for Greater Antiseptic Stewardship

mSphere ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Patrick T. LaBreck ◽  
Audrey C. Bochi-Layec ◽  
Joshua Stanbro ◽  
Gina Dabbah-Krancher ◽  
Mark P. Simons ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Transcriptional Analysis ◽  
Systematic Analysis ◽  
Daily Lives ◽  
Single Strain ◽  
Content Type ◽  
Subinhibitory Concentrations ◽  
Different Strains

ABSTRACT Staphylococcus aureus-associated infections can be difficult to treat due to multidrug resistance. Thus, infection prevention is critical. Cationic antiseptics, such as chlorhexidine (CHX) and benzalkonium chloride (BKC), are liberally used in health care and community settings to prevent infection. However, increased administration of antiseptics has selected for S. aureus strains that show reduced susceptibilities to cationic antiseptics. This increased resistance has been associated with carriage of specific efflux pumps (QacA, QacC, and NorA). Since prior published studies focused on different strains and on strains carrying only a single efflux gene, the relative importance of these various systems to antiseptic resistance is difficult to ascertain. To overcome this, we engineered a collection of isogenic S. aureus strains that harbored norA, qacA, and qacC, individually or in combination. MIC assays showed that qacA was associated with increased resistance to CHX, cetrimide (CT), and BKC, qacC was associated with resistance to CT and BKC, and norA was necessary for basal-level resistance to the majority of tested antiseptics. When all three pumps were present in a single strain, an additive effect was observed in the MIC for CT. Transcriptional analysis revealed that expression of qacA and norA was significantly induced following exposure to BKC. Alarmingly, in a strain carrying qacA and norA, preexposure to BKC increased CHX tolerance. Overall, our results reveal increased antiseptic resistance in strains carrying multiple efflux pumps and indicate that preexposure to BKC, which is found in numerous daily-use products, can increase CHX tolerance. IMPORTANCE S. aureus remains a significant cause of disease within hospitals and communities. To reduce the burden of S. aureus infections, antiseptics are ubiquitously used in our daily lives. Furthermore, many antiseptic compounds are dual purpose and are found in household products. The increased abundance of antiseptic compounds has selected for S. aureus strains that carry efflux pumps that increase resistance to antiseptic compounds; however, the effect of carrying multiple pumps within S. aureus is unclear. We demonstrated that an isogenic strain carrying multiple efflux pumps had an additive resistance phenotype to cetrimide. Moreover, in a strain carrying qacA and norA, increased chlorhexidine tolerance was observed after the strain was preexposed to subinhibitory concentrations of a different common-use antiseptic. Taken together, our findings demonstrate cooperation between antiseptic resistance efflux pumps and suggest that their protective phenotype may be exacerbated by priming with subinhibitory concentrations of household antiseptics.

Folic acid-modified mesoporous silica nanoparticles with pH-responsiveness loaded with Amp for an enhanced effect against anti-drug-resistant bacteria by overcoming efflux pump systems

2018 ◽  
Vol 6 (7) ◽  
pp. 1923-1935 ◽  
Author(s):  
Xu Chen ◽  
Yanan Liu ◽  
Ange Lin ◽  
Na Huang ◽  
Liquan Long ◽  
...  
Keyword(s):  
Folic Acid ◽  
Multidrug Resistance ◽  
Mesoporous Silica ◽  
Efflux Pump ◽  
Mesoporous Silica Nanoparticles ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Pump System ◽  
Drug Resistant Bacteria ◽  
Antibiotic Failure

Efflux pump system-mediated bacterial multidrug resistance is one of the main causes of antibiotic failure.

scholarly journals Clinically Relevant Chromosomally Encoded Multidrug Resistance Efflux Pumps in Bacteria

2006 ◽  
Vol 19 (2) ◽  
pp. 382-402 ◽  
Author(s):  
Laura J. V. Piddock
Keyword(s):  
Antibiotic Resistance ◽  
Drug Transport ◽  
Efflux Pump ◽  
Regulatory Gene ◽  
Structural Data ◽  
Efflux Pumps ◽  
Resistant Bacteria ◽  
Multiple Drug ◽  
Transporter Gene ◽  
Resistance Nodulation Division

SUMMARY Efflux pump genes and proteins are present in both antibiotic-susceptible and antibiotic-resistant bacteria. Pumps may be specific for one substrate or may transport a range of structurally dissimilar compounds (including antibiotics of multiple classes); such pumps can be associated with multiple drug (antibiotic) resistance (MDR). However, the clinical relevance of efflux-mediated resistance is species, drug, and infection dependent. This review focuses on chromosomally encoded pumps in bacteria that cause infections in humans. Recent structural data provide valuable insights into the mechanisms of drug transport. MDR efflux pumps contribute to antibiotic resistance in bacteria in several ways: (i) inherent resistance to an entire class of agents, (ii) inherent resistance to specific agents, and (iii) resistance conferred by overexpression of an efflux pump. Enhanced efflux can be mediated by mutations in (i) the local repressor gene, (ii) a global regulatory gene, (iii) the promoter region of the transporter gene, or (iv) insertion elements upstream of the transporter gene. Some data suggest that resistance nodulation division systems are important in pathogenicity and/or survival in a particular ecological niche. Inhibitors of various efflux pump systems have been described; typically these are plant alkaloids, but as yet no product has been marketed.

scholarly journals Ethidium Bromide MIC Screening for Enhanced Efflux Pump Gene Expression or Efflux Activity in Staphylococcus aureus

2010 ◽  
Vol 54 (12) ◽  
pp. 5070-5073 ◽  
Author(s):  
Diixa Patel ◽  
Christos Kosmidis ◽  
Susan M. Seo ◽  
Glenn W. Kaatz
Keyword(s):  
Staphylococcus Aureus ◽  
Ethidium Bromide ◽  
Efflux Pump ◽  
Large Strain ◽  
Efflux Pumps ◽  
Multidrug Resistant ◽  
Reverse Transcription Pcr ◽  
Biocide Resistance ◽  
Straightforward Method ◽  
Short Period

ABSTRACT Multidrug resistance efflux pumps contribute to antimicrobial and biocide resistance in Staphylococcus aureus. The detection of strains capable of efflux is time-consuming and labor-intensive using currently available techniques. A simple and inexpensive method to identify such strains is needed. Ethidium bromide is a substrate for all but one of the characterized S. aureus multidrug-resistant (MDR) efflux pumps (NorC), leading us to examine the utility of simple broth microtiter MIC determinations using this compound in identifying efflux-proficient strains. Quantitative reverse transcription-PCR identified the increased expression of one or more MDR efflux pump genes in 151/309 clinical strains (49%). Ethidium bromide MIC testing was insensitive (48%) but specific (92%) in identifying strains with gene overexpression, but it was highly sensitive (95%) and specific (99%) in identifying strains capable of ethidium efflux. The increased expression of norA with or without other genes was most commonly associated with efflux, and in the majority of cases that efflux was inhibited by reserpine. Ethidium bromide MIC testing is a simple and straightforward method to identify effluxing strains and can provide accurate predictions of efflux prevalence in large strain sets in a short period of time.

scholarly journals Transcriptional Regulator TetR21 Controls the Expression of the Staphylococcus aureus LmrS Efflux Pump

2017 ◽  
Vol 61 (8) ◽  
Author(s):  
Q. C. Truong-Bolduc ◽  
Y. Wang ◽  
C. Chen ◽  
D. C. Hooper
Keyword(s):  
Staphylococcus Aureus ◽  
Parental Strain ◽  
Efflux Pump ◽  
Transcriptional Regulator ◽  
Fold Increase ◽  
Efflux Pumps ◽  
Transcription Level ◽  
Content Type

ABSTRACT TetR21 controls the expression of Tet38 and LmrS efflux pumps. A tetR21 mutant, QT21, exhibited a 4-fold increase in the transcription level of lmrS. Staphylococcus aureus lmrS overexpressor showed increases of 4-fold and 2-fold, respectively, in the MICs of chloramphenicol and erythromycin, while the MICs of lmrS mutant QT18 and lmrS-tetR21 mutant QT1821 remained similar to those of parental strain RN6390. TetR21 does not bind to the promoter of lmrS, suggesting indirect regulation of lmrS.

Copper nanoparticles as an efflux pump inhibitor to tackle drug resistant bacteria

RSC Advances ◽  
2015 ◽  
Vol 5 (17) ◽  
pp. 12899-12909 ◽  
Author(s):  
Lowrence Rene Christena ◽  
Vimalanathan Mangalagowri ◽  
Prabhakaran Pradheeba ◽  
Khan Behlol Ayaz Ahmed ◽  
Bastin Infanta Sandhiya Shalini ◽  
...  
Keyword(s):  
Copper Nanoparticles ◽  
Efflux Pump ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Efflux Pump Inhibitor ◽  
Drug Resistant Bacteria

Casein capped copper nanoparticles at sub inhibitory concentrations function as an efflux pump inhibitor and restores susceptibility to antibiotics in drug resistant bacteria.

scholarly journals Dynamic Boolean modelling reveals the influence of energy supply on bacterial efflux pump expression

2021 ◽  
Author(s):  
Ryan Kerr ◽  
Sara Jabbari ◽  
Jessica M A Blair ◽  
Iain Johnston
Keyword(s):  
Gene Expression ◽  
Antimicrobial Resistance ◽  
Energy Supply ◽  
Regulatory Networks ◽  
Efflux Pump ◽  
Bacterial Species ◽  
Efflux Pumps ◽  
Resistant Bacteria ◽  
Energy Availability ◽  
Bacterial Populations

Antimicrobial resistance (AMR) is a global health issue. One key factor contributing to AMR is the ability of bacteria to export drugs through efflux pumps, which relies on the ATP-dependent expression and interaction of several controlling genes. Recent studies have shown significant cell-to-cell ATP variability exists within clonal bacterial populations, but the contribution of intrinsic cell-to-cell ATP heterogeneity is generally overlooked in understanding efflux pumps. Here, we consider how ATP variability influences gene regulatory networks controlling expression of efflux pump genes in two bacterial species. We develop and apply a generalisable Boolean modelling framework, developed to incorporate the dependence of gene expression dynamics on available cellular energy supply. Theoretical results show differences in energy availability can cause pronounced downstream heterogeneity in efflux gene expression. Cells with higher energy availability have a superior response to stressors. Further, in the absence of stress, model bacteria develop heterogeneous pulses of efflux pump gene expression which contribute to a sustained sub-population of cells with increased efflux expression activity, potentially conferring a continuous pool of intrinsically resistant bacteria. This modelling approach thus reveals an important source of heterogeneity in cell responses to antimicrobials and sheds light on potentially targetable aspects of efflux pump-related antimicrobial resistance.

scholarly journals Quorum-Sensing Regulation of Antimicrobial Resistance in Bacteria

2020 ◽  
Vol 8 (3) ◽  
pp. 425 ◽  
Author(s):  
Xihong Zhao ◽  
Zixuan Yu ◽  
Tian Ding
Keyword(s):  
Quorum Sensing ◽  
Efflux Pump ◽  
Cell Communication ◽  
Quorum Quenching ◽  
Resistance Mechanisms ◽  
Resistant Bacteria ◽  
Microbial Resistance ◽  
Sensing Systems ◽  
Drug Resistant Bacteria ◽  
New Strategy

Quorum sensing is a cell-to-cell communication system that exists widely in the microbiome and is related to cell density. The high-density colony population can generate a sufficient number of small molecule signals, activate a variety of downstream cellular processes including virulence and drug resistance mechanisms, tolerate antibiotics, and harm the host. This article gives a general introduction to the current research status of microbial quorum-sensing systems, focuses on the role of quorum-sensing systems in regulating microbial resistance mechanisms, such as drug efflux pump and microbial biofilm formation regulation, and discusses a new strategy for the treatment of drug-resistant bacteria proposed by using quorum quenching to prevent microbial resistance.

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