Combination approaches to combat multidrug-resistant bacteria

Worthington, Roberta J.; Melander, Christian

doi:10.1016/j.tibtech.2012.12.006

Cited by 526 publications

(389 citation statements)

References 62 publications

Supporting

Mentioning

380

Contrasting

Unclassified

Order By: Relevance

“…The primary active component in extracts of the creosote plant, nordihydroguaiaretic acid is a redox-active compound that appears to target the cellular membrane and can disrupt biofilm structure (86). Benserazide is an aromatic L-amino acid decarboxylase inhibitor that is coadministered with levodopa to treat Parkinson's disease and has been shown to increase the sensitivity of multidrugresistant Pseudomonas aeruginosa to minocycline (87).…”

Section: Figmentioning

confidence: 99%

Deciphering the Function of New Gonococcal Vaccine Antigens Using Phenotypic Microarrays

et al. 2017

View full text Add to dashboard Cite

The function and extracellular location of cell envelope proteins make them attractive candidates for developing vaccines against bacterial diseases, including challenging drug-resistant pathogens, such as Neisseria gonorrhoeae. A proteomicsdriven reverse vaccinology approach has delivered multiple gonorrhea vaccine candidates; however, the biological functions of many of them remain to be elucidated. Herein, the functions of six gonorrhea vaccine candidates-NGO2121, NGO1985, NGO2054, NGO2111, NGO1205, and NGO1344 -in cell envelope homeostasis were probed using phenotype microarrays under 1,056 conditions and a ΔbamE mutant (Δngo1780) as a reference of perturbed outer membrane integrity. Optimal growth conditions for an N. gonorrhoeae phenotype microarray assay in defined liquid medium were developed, which can be useful in other applications, including rapid and thorough antimicrobial susceptibility assessment. Our studies revealed 91 conditions having uniquely positive or negative effects on one of the examined mutants. A cluster analysis of 37 and 57 commonly beneficial and detrimental compounds, respectively, revealed three separate phenotype groups: NGO2121 and NGO1985; NGO1344 and BamE; and the trio of NGO1205, NGO2111, and NGO2054, with the last protein forming an independent branch of this cluster. Similar phenotypes were associated with loss of these vaccine candidates in the highly antibiotic-resistant WHO X strain. Based on their extensive sensitivity phenomes, NGO1985 and NGO2121 appear to be the most promising vaccine candidates. This study establishes the principle that phenotype microarrays can be successfully applied to a fastidious bacterial organism, such as N. gonorrhoeae. IMPORTANCE Innovative approaches are required to develop vaccines against prevalent and neglected sexually transmitted infections, such as gonorrhea. Herein, we have utilized phenotype microarrays in the first such investigation into Neisseria gonorrhoeae to probe the function of proteome-derived vaccine candidates in cell envelope homeostasis. Information gained from this screening can feed the vaccine candidate decision tree by providing insights into the roles these proteins play in membrane permeability, integrity, and overall N. gonorrhoeae physiology. The optimized screening protocol can be applied in investigations into the function of other hypothetical proteins of N. gonorrhoeae discovered in the expanding number of whole-genome sequences, in addition to revealing phenotypic differences between clinical and laboratory strains.KEYWORDS Neisseria gonorrhoeae, vaccine antigens, cell envelope, phenotypic microarrays, antibiotics, Biolog I n Gram-negative bacteria, the cell envelope is composed of the outer membrane, the cell wall, and the cytoplasmic or inner membrane, each of which can be further broken down into its constituents (1). The outer membrane is a bilayer composed of a lipopolysaccharide (LPS) or lipooligosaccharide (LOS) outer leaflet facing the extracel-

show abstract

Section: Figmentioning

confidence: 99%

Deciphering the Function of New Gonococcal Vaccine Antigens Using Phenotypic Microarrays

et al. 2017

View full text Add to dashboard Cite

show abstract

“…ultidrug-resistant pathogens pose a serious threat in modern chemotherapy (1)(2)(3)(4)(5). Intrinsic multidrug efflux transporters serve as a self-defense mechanism in bacterial cells; hence, the overexpression of efflux transporters causes multidrug resistance (6,7).…”

mentioning

confidence: 99%

AcrB-AcrA Fusion Proteins That Act as Multidrug Efflux Transporters

et al. 2016

View full text Add to dashboard Cite

The AcrAB-TolC system in Escherichia coli is an intrinsic RND-type multidrug efflux transporter that functions as a tripartite complex of the inner membrane transporter AcrB, the outer membrane channel TolC, and the adaptor protein AcrA. Although the crystal structures of each component of this system have been elucidated, the crystal structure of the whole complex has not been solved. The available crystal structures have shown that AcrB and TolC function as trimers, but the number of AcrA molecules in the complex is now under debate. Disulfide chemical cross-linking experiments have indicated that the stoichiometry of AcrB-AcrA-TolC is 1:1:1; on the other hand, recent cryo-electron microscopy images of AcrAB-TolC suggested a 1:2:1 stoichiometry. In this study, we constructed 1:1-fixed AcrB-AcrA fusion proteins using various linkers. Surprisingly, all the 1:1-fixed linker proteins showed drug export activity under both acrAB-deficient conditions and acrAB acrEF double-pump-knockout conditions regardless of the lengths of the linkers. Finally, we optimized a shorter linker lacking the conformational freedom imparted by the AcrB C terminus. These results suggest that a complex with equal amounts of AcrA and AcrB is sufficient for drug export function. IMPORTANCEThe structure and stoichiometry of the RND-type multidrug exporter AcrB-AcrA-TolC complex are still under debate. Recently, electron microscopic images of the AcrB-AcrA-TolC complex have been reported, suggesting a 1:2:1 stoichiometry. However, we report here that the AcrB-AcrA 1:1 fusion protein is active for drug export under acrAB-deficient conditions and also under acrAB acrEF double-deficient conditions, which eliminate the aid of free AcrA and its close homolog AcrE, indicating that the AcrB-AcrA 1:1 stoichiometry is enough for drug export function. In addition, the AcrB-AcrA fusion protein can function without the aid of free AcrA. We believe that these results are very important for considering the structure and mechanism of AcrABTolC-mediated multidrug export.

show abstract

“…Decoration of CNTs by lipid molecules is anticipated to minimize their toxicity while improving the biocompatibility. The prospect of loading functional molecules within the lipid self-assembly as well as on the CNT surface provide limitless potential to the CNTstabilized lipid particles in the area of biomedical sciences especially in the context of combination therapies against major diseases 73 .…”

Section: Lipid Coating Of Cntsmentioning

confidence: 99%

Facile Preparation of Internally Self-assembled Lipid Particles Stabilized by Carbon Nanotubes

Patil-Sen

Sadeghpour

Rappolt

et al. 2016

JoVE

View full text Add to dashboard Cite

We present a facile method to prepare nanostructured lipid particles stabilized by carbon nanotubes (CNTs). Single-walled (pristine) and multiwalled (functionalized) CNTs are used as stabilizers to produce Pickering type oil-in-water (O/W) emulsions. Lipids namely, Dimodan U and Phytantriol are used as emulsifiers, which in excess water self-assemble into the bicontinuous cubic Pn3m phase. This highly viscous phase is fragmented into smaller particles using a probe ultrasonicator in presence of conventional surfactant stabilizers or CNTs as done here. Initially, the CNTs (powder form) are dispersed in water followed by further ultrasonication with the molten lipid to form the final emulsion. During this process the CNTs get coated with lipid molecules, which in turn are presumed to surround the lipid droplets to form a particulate emulsion that is stable for months. The average size of CNT-stabilized nanostructured lipid particles is in the submicron range, which compares well with the particles stabilized using conventional surfactants. Small angle X-ray scattering data confirms the retention of the original Pn3m cubic phase in the CNT-stabilized lipid dispersions as compared to the pure lipid phase (bulk state). Blue shift and lowering of the intensities in characteristic G and G' bands of CNTs observed in Raman spectroscopy characterize the interaction between CNT surface and lipid molecules. These results suggest that the interactions between the CNTs and lipids are responsible for their mutual stabilization in aqueous solutions. As the concentrations of CNTs employed for stabilization are very low and lipid molecules are able to functionalize the CNTs, the toxicity of CNTs is expected to be insignificant while their biocompatibility is greatly enhanced. Hence the present approach finds a great potential in various biomedical applications, for instance, for developing hybrid nanocarrier systems for the delivery of multiple functional molecules as in combination therapy or polytherapy. Video LinkThe video component of this article can be found at

show abstract

Combination approaches to combat multidrug-resistant bacteria

Cited by 526 publications

References 62 publications

Deciphering the Function of New Gonococcal Vaccine Antigens Using Phenotypic Microarrays

Deciphering the Function of New Gonococcal Vaccine Antigens Using Phenotypic Microarrays

AcrB-AcrA Fusion Proteins That Act as Multidrug Efflux Transporters

Facile Preparation of Internally Self-assembled Lipid Particles Stabilized by Carbon Nanotubes

Contact Info

Product

Resources

About