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Quorum sensing inhibition, Pseudomonas aeruginosa

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https://www.readbyqxmd.com/read/28096154/influence-of-rhlr-and-lasr-on-polymyxin-pharmacodynamics-in-pseudomonas-aeruginosa-implications-for-quorum-sensing-inhibition-with-azithromycin
#1
Zackery P Bulman, Neang S Ly, Justin R Lenhard, Patricia N Holden, Jürgen B Bulitta, Brian T Tsuji
Quorum sensing's impact on polymyxin and azithromycin pharmacodynamics was assessed in Pseudomonas aeruginosa PAO1 and an isogenic rhlR/lasR double knockout. For polymyxin B, greater killing against the rhlR/lasR knockout versus PAO1 was observed at 10(8) CFU/mL(polymyxin B EC50:5.61 versus 12.5mg/L, respectively; p<0.005). Polymyxin B combined with azithromycin (256mg/L) was synergistic against each strain, significantly reducing the respective polymyxin B EC50 compared to monotherapy (p<0.005), and is a promising strategy to combat P...
January 17, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28094526/1h-nmr-based-global-metabolic-studies-of-pseudomonas-aeruginosa-upon-exposure-of-the-quorum-sensing-inhibitor-resveratrol
#2
Tongtong Chen, Jiyang Sheng, Yonghong Fu, Ming-Hui Li, Jun-Song Wang, Aiqun Jia
Quorum sensing (QS) is a process of bacterial communication that has been a novel target for drug discovery. Pyocyanin quantification assay confirmed that resveratrol was an effective quorum sensing inhibitor (QSI) against Pseudomonas aeruginosa PAO1. In this study, the global metabolite changes of P. aeruginosa PAO1 exposed to QSI resveratrol were investigated by 1H-NMR spectroscopy. A total of 40 metabolites containing amino acids, organic acid, organic amine and energy storage compounds were identified. The changed metabolic profile indicated that resveratrol influenced pathways including oxidative stress, protein synthesis and energy metabolism...
January 17, 2017: Journal of Proteome Research
https://www.readbyqxmd.com/read/28075113/pseudomonas-aeruginosa-lasr%C3%A2-dna-binding-is-directly-inhibited-by-quorum-sensing-antagonists
#3
Emma G Suneby, Leslie R Herndon, Tanya L Schneider
Inhibition of quorum sensing in Pseudomonas aeruginosa is of interest as a possible antivirulence strategy for this pathogenic bacterium. The LasR regulator protein is important in coordinating gene expression in response to quorum sensing signaling molecules. One predominant strategy for LasR inhibition is the development of small-molecule antagonists that mimic the native autoinducer, though the mechanism by which they inactivate LasR is not known. This work reveals that multiple antagonists function by binding to and stabilizing LasR in a conformation that renders it unable to bind DNA...
January 11, 2017: ACS Infectious Diseases
https://www.readbyqxmd.com/read/28065820/bioavailability-enhanced-resveramax%C3%A2-modulates-quorum-sensing-and-inhibits-biofilm-formation-in-pseudomonas-aeruginosa-pao1
#4
H S Vasavi, H V Sudeep, H B Lingaraju, K Shyam Prasad
Quorum sensing (QS), a cell-to-cell communication mechanism present in many bacterial species plays a key role in regulating the virulence factor and biofilm formation in many pathogens, which causes severe public health risk. Therefore, interfering with QS mechanism offers an attractive strategy to combat bacterial infections. In the present study, anti-QS activity of a novel resveratrol formulation, Resveramax™, was detected using Chromobacterium violaceum biosensor bioassay and the effect of Resveramax on QS-regulated phenotypes in Pseudomonas aeruginosa PAO1 was assessed by standard protocols...
January 5, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28062182/exposure-of-airway-epithelial-cells-to-pseudomonas-aeruginosa-biofilm-derived-quorum-sensing-molecules-decrease-the-activity-of-the-anti-oxidant-response-element-bound-by-nrf2
#5
Lucie Roussel, Simon Rousseau
Chronic bacterial infections in cystic fibrosis lung disease are often characterized by Pseudomonas aeruginosa biofilms that are regulated by bacterial intercellular signals termed quorum sensing (QS), such as N-(3-oxododecanoyl)-l-homoserine lactone (3OC12-HSL). This study reports that biofilm-derived exoproducts decrease the transcriptional activity of the anti-oxidant response element in bronchial epithelial cells. In a live co-culture assay of BEAS-2B cells and P. aeruginosa biofilm, the QS molecule 3OC12-HSL was an important but not sole contributor to the inhibition of basal NRF2 luciferase reporter activity...
January 4, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28056745/exploiting-quorum-sensing-inhibition-for-the-control-of-pseudomonas-aeruginosa-and-acinetobacter-baumannii-biofilms
#6
Israel Castillo-Juarez, Luis Esaú López-Jácome, Gloria Soberón-Chávez, María Tomás, Jintae Lee, Paulina Castañeda-Tamez, Iván Ángelo Hernández-Bárragan, Martha Yumiko Cruz-Muñiz, Toshinari Maeda, Thomas K Wood, Rodolfo García-Contreras
Pseudomonas aeruginosa and Acinetobacter baumannii are two of the main bacteria responsible for nosocomial infections; both organisms are resistant to several classes of antibiotics making their infections very difficult to treat. Moreover, they possess a remarkable ability to form biofilms, which further enhances their antimicrobial resistance. Both organisms coordinate their formation of biofilms and their expression of virulence factors through quorum sensing, a system that regulates gene expression at high cell densities and that plays a key role in the establishment of bacterial infections...
January 5, 2017: Current Topics in Medicinal Chemistry
https://www.readbyqxmd.com/read/28035685/a-medicinal-herb-cassia-alata-attenuates-quorum-sensing-in-chromobacterium-violaceum-and-pseudomonas-aeruginosa
#7
P D Rekha, H S Vasavi, C Vipin, K Saptami, A B Arun
Quorum sensing (QS) has been shown to play a crucial role in the pathogenesis in many bacteria and attenuation of QS is one of the targets of antimicrobial therapy with particular interest in combating drug resistance. This study reports the QS inhibitory activity of metabolites from Cassia alata L. (Ca. alata), an important medicinal herb widely used in the treatment of microbial infections. For investigating the QS inhibition (QSI) potential of Ca. alata L., initially, metabolites of the leaves extracted using ethanol were tested against biosensor strain Chromobacterium violaceum CV026 and C...
December 30, 2016: Letters in Applied Microbiology
https://www.readbyqxmd.com/read/28033578/fusaric-acid-and-analogues-as-gram-negative-bacterial-quorum-sensing-inhibitors
#8
Truong Thanh Tung, Tim Holm Jakobsen, Trong Tuan Dao, Anja Thoe Fuglsang, Michael Givskov, Søren Brøgger Christensen, John Nielsen
Taking advantage of microwave-assisted synthesis, efficient and expedite procedures for preparation of a library of fusaric acid and 39 analogues are reported. The fusaric acid analogues were tested in cell-based screening assays for inhibition of the las and rhl quorum sensing system in Pseudomonas aeruginosa and the lux quorum sensing system in Vibrio fischeri. Eight of the 40 compounds in the library including fusaric acid inhibited lux quorum sensing and one compound inhibited activity of the las quorum sensing system...
November 24, 2016: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28010047/distal-and-proximal-promoters-co-regulate-pqsr-expression-in-pseudomonas-aeruginosa
#9
John M Farrow, Everett C Pesci
The ubiquitous bacterium Pseudomonas aeruginosa is an opportunistic pathogen that can cause serious infections in immunocompromised individuals. P. aeruginosa virulence is controlled partly by intercellular communication, and the transcription factor PqsR is a necessary component in the P. aeruginosa cell-to-cell signaling network. PqsR acts as the receptor for the Pseudomonas quinolone signal, and it controls the production of 2-alkyl-4-quinolone molecules which are important for pathogenicity. Previous studies showed that the expression of pqsR is positively controlled by the quorum-sensing regulator LasR, but it was unclear how LasR is able to induce pqsR transcription...
December 23, 2016: Molecular Microbiology
https://www.readbyqxmd.com/read/27999062/5-hydroxyethyl-3-tetradecanoyltetramic-acid-represents-a-novel-treatment-for-intravascular-catheter-infections-due-to-staphylococcus-aureus
#10
Marta Zapotoczna, Ewan J Murray, Siobhan Hogan, James P O'Gara, Siri R Chhabra, Weng C Chan, Eoghan O'Neill, Paul Williams
OBJECTIVES: Biofilm infections of intravascular catheters caused by Staphylococcus aureus may be treated with catheter lock solutions (CLSs). Here we investigated the antibacterial activity, cytotoxicity and CLS potential of 5-hydroxyethyl-3-tetradecanoyltetramic acid (5HE-C14-TMA) compared with the related compounds 3-tetradecanoyltetronic (C14-TOA) and 3-tetradecanoylthiotetronic (C14-TTA), which are variants of quorum sensing signalling molecules produced by Pseudomonas aeruginosa METHODS: Antibacterial activity and mechanism of action of 5HE-C14-TMA, C14-TOA and C14-TTA were determined via MIC, bacterial killing, membrane potential and permeability assays...
December 20, 2016: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/27977197/disulfide-bond-containing-ajoene-analogues-as-novel-quorum-sensing-inhibitors-of-pseudomonas-aeruginosa
#11
July Fong, Mingjun Yuan, Tim Holm Jakobsen, Kim T Mortensen, May Margarette Salido Delos Santos, Song Lin Chua, Liang Yang, Choon Hong Tan, Thomas E Nielsen, Michael Givskov
Since its discovery 22 years ago, the bacterial cell-to-cell communication system, termed quorum sensing (QS), has shown potential as antipathogenic target. Previous studies reported that ajoene from garlic inhibits QS in opportunistic human pathogen Pseudomonas aeruginosa. In this study, screening of an in-house compound library revealed two sulfur-containing compounds which possess structural resemblance with ajoene and inhibit QS in bioreporter assay. Following a quantitative structure-activity relationship (SAR) study, 25 disulfide bond-containing analogues were synthesized and tested for QS inhibition activities...
December 28, 2016: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/27902410/inhibition-of-quorum-sensing-controlled-virulence-factors-of-pseudomonas-aeruginosa-by-murraya-koenigii-essential-oil-a-study-in-a-caenorhabditis-elegans-infectious-model
#12
P Sankar Ganesh, Ravishankar Vittal Rai
The global emergence of antibiotic-resistant strains of Pseudomonas aeruginosa poses a major threat in both hospital environments and the community. P. aeruginosa is an opportunistic human pathogen, and it also infects a wide range of model organisms including the nematode Caenorhabditis elegans. Quorum sensing (QS) mediates cell-to-cell communication in bacteria and has an important role in regulating virulence genes, antibiotic resistance and biofilm formation, which are crucial for establishment of the infection...
December 2016: Journal of Medical Microbiology
https://www.readbyqxmd.com/read/27896412/the-bacterial-quorum-sensing-molecule-n-3-oxo-dodecanoyl-l-homoserine-lactone-inhibits-mediator-release-and-chemotaxis-of-murine-mast-cells
#13
Ibrahim Khambati, Sangsu Han, Daniëlle Pijnenburg, Hannah Jang, Paul Forsythe
OBJECTIVE: Bacterial colonization relies on communication between bacteria via so-called "quorum-sensing molecules", which include the acyl-homoserine lactone group. Certain acyl-homoserine lactones can modulate mammalian cell function and are thought to contribute to bacterial pathogenicity. Given the role of mast cells in host defense, we investigated the ability of acyl-homoserine lactones to modulate mast cell function. METHODS: We utilized murine primary mast cell cultures to assess the effect of acyl-homoserine lactones on degranulation and cytokine release in response to different stimuli...
November 28, 2016: Inflammation Research: Official Journal of the European Histamine Research Society ... [et Al.]
https://www.readbyqxmd.com/read/27874198/crataeva-nurvala-nanoparticles-inhibit-virulence-factors-and-biofilm-formation-in-clinical-isolates-of-pseudomonas-aeruginosa
#14
Syed Ghazanfar Ali, Mohammad Azam Ansari, Haris M Khan, Mohammad Jalal, Abbas Ali Mahdi, Swaranjit Singh Cameotra
Green synthesized nanoparticles have gained great attention due to their non-toxic and non-hazardous nature. In the present study, bark extract of the medicinal plant in Ayurveda Crataeva nurvala (Buch-Ham) (CN) was chosen for the biosynthesis of silver nanoparticles (AgNPs). These NPs were characterized by Ultra violet visible spectroscopy, Fourier Transform Infra Red, Atomic Force Microscopy, and Transmission Electron Microscopy (TEM). The average particle size of green synthesized CN-AgNPs was 15.2 ± 1...
November 22, 2016: Journal of Basic Microbiology
https://www.readbyqxmd.com/read/27864804/activity-of-norspermidine-on-bacterial-biofilms-of-multidrug-resistant-clinical-isolates-associated-with-persistent-extremity-wound-infections
#15
Anthony P Cardile, Ronald L Woodbury, Carlos J Sanchez, Sandra C Becerra, Rebecca A Garcia, Katrin Mende, Joseph C Wenke, Kevin S Akers
Biofilm formation is a major virulence factor for numerous pathogenic bacteria and is cited as a central event in the pathogenesis of chronic human infections, which is in large part due to excessive extracellular matrix secretion and metabolic changes that occur within the biofilm rendering them highly tolerant to antimicrobial treatments. Polyamines, including norspermidine, play central roles in bacterial biofilm development, but have also recently been shown to inhibit biofilm formation in select strains of various pathogenic bacteria...
November 19, 2016: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/27834332/attenuation-of-quorum-sensing-regulated-behaviour-by-tinospora-cordifolia-extract-identification-of-its-active-constituents
#16
Viraj C Gala, Nithya R John, Ashok M Bhagwat, Ajit G Datar, Prashant S Kharkar, Krutika B Desai
BACKGROUND & OBJECTIVES: The pathogenicity of the nosocomial pathogens, Pseudomonas aeruginosa and Acinetobacter baumannii is regulated by their quorum sensing (QS) systems. The objective of the present study was to examine the effect of the cold ethyl acetate extract of Tinospora cordifolia stem on virulence and biofilm development in the wild type and clinical strains of P. aeruginosa and A. baumannii. The study was further aimed to identify the probable active constituents in the plant extract...
July 2016: Indian Journal of Medical Research
https://www.readbyqxmd.com/read/27784787/epigallocatechin-gallate-remodels-overexpressed-functional-amyloids-in-pseudomonas-aeruginosa-and-increases-biofilm-susceptibility-to-antibiotic-treatment
#17
Marcel Stenvang, Morten S Dueholm, Brian S Vad, Thomas Seviour, Guanghong Zeng, Susana Geifman-Shochat, Mads T Søndergaard, Gunna Christiansen, Rikke Louise Meyer, Staffan Kjelleberg, Per Halkjær Nielsen, Daniel E Otzen
Epigallocatechin-3-gallate (EGCG) is the major polyphenol in green tea. It has antimicrobial properties and disrupts the ordered structure of amyloid fibrils involved in human disease. The antimicrobial effect of EGCG against the opportunistic pathogen Pseudomonas aeruginosa has been shown to involve disruption of quorum sensing (QS). Functional amyloid fibrils in P. aeruginosa (Fap) are able to bind and retain quorum-sensing molecules, suggesting that EGCG interferes with QS through structural remodeling of amyloid fibrils...
December 16, 2016: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/27756390/determination-of-n-acylhomoserine-lactones-of-pseudomonas-aeruginosa-in-clinical-samples-from-dogs-with-otitis-externa
#18
Darja Kušar, Karin Šrimpf, Petra Isaković, Lina Kalšek, Javid Hosseini, Irena Zdovc, Tina Kotnik, Modest Vengušt, Gabrijela Tavčar-Kalcher
BACKGROUND: Bacterial intercellular communication, called quorum sensing, takes place via the production and collective response to signal molecules. In Gram-negative bacteria, like Pseudomonas aeruginosa, these signaling molecules are N-acylhomoserine lactones (AHLs). P. aeruginosa is a common cause of inflammation of the ear canal (otitis externa) in dogs. It employs quorum sensing to coordinate the expression of host tissue-damaging factors, which are largely responsible for its virulence...
October 18, 2016: BMC Veterinary Research
https://www.readbyqxmd.com/read/27702795/prevention-of-polymicrobial-biofilms-composed-of-pseudomonas-aeruginosa-and-pathogenic-fungi-by-essential-oils-from-selected-citrus-species
#19
Marina Pekmezovic, Ivana Aleksic, Aleksandra Barac, Valentina Arsic-Arsenijevic, Branka Vasiljevic, Jasmina Nikodinovic-Runic, Lidija Senerovic
Mixed microbial infections caused by Pseudomonas aeruginosa and pathogenic fungi are commonly found in patients with chronic infections and constitute a significant health care burden. The aim of this study was to address the potential polymicrobial antibiofilm activity of pompia and grapefruit essential oils (EOs). The mechanism of antimicrobial activity of EOs was analysed. EOs of pompia and grapefruit inhibited fungal growth with MIC concentrations between 50 and 250 mg L(-1), whereas no effect on P. aeruginosa growth was observed...
November 2016: Pathogens and Disease
https://www.readbyqxmd.com/read/27696655/coprinuslactone-protects-the-edible-mushroom-coprinus-comatus-against-biofilm-infections-by-blocking-both-quorum-sensing-and-mura
#20
Maira P de Carvalho, Giuseppe Gulotta, Matheus W do Amaral, Heinrich Lünsdorf, Florenz Sasse, Wolf-Rainer Abraham
Pathogens embedded in biofilms are involved in many infections and are very difficult to treat with antibiotics because of higher resistance compared with planktonic cells. Therefore, new approaches for their control are urgently needed. One way to search for biofilm dispersing compounds is to look at defense strategies of organisms exposed to wet environments, which makes them prone to biofilm infections. It is reasonable to assume that mushrooms have developed mechanisms to control biofilms on their sporocarps (fruiting bodies)...
November 2016: Environmental Microbiology
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