Pseudomonas

Résumé

Les bactéries du genre Pseudomonas peuvent être définies par :

Bacilles à Gram négatif, oxydase + ;
Aérobies stricts (« Respiration nitrate » chez certaines espèces) ;
Dégradant le glucose par respiration aérobie ou inerte vis-à-vis du glucose. Ils n'attaquent pas les sucres ou les attaquent par voie oxydative et non fermentative ;
Généralement mobiles par ciliature polaire (monotriche ou lophotriche) ;
Peu exigeantes, cultivant de ;
Indole - ;
Asporulés ;
Colonies souvent pigmentées.

Au début des années 2000, on considère que la famille des Pseudomonacées regroupe probablement la forme de vie la plus abondante et la plus répandue sur la planète. Ce genre comprend en effet plus d'une centaine d'espèces ubiquitaires (dont l'espèce-type est Pseudomonas aeruginosa, généralement appelée Bacille pyocyanique). Cependant, ce nombre se réduit car les progrès de la phylogénétique permettent d'affiner le classement. On tend vers une soixantaine d'espèces. Habitat

Source officielle

https://fr.wikipedia.org/wiki/Pseudomonas

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Publications associées (36)

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P. aeruginosa (PA) continues to pose a threat to global public health due to its high levels of antimicrobial resistance (AMR). The ongoing AMR crisis has led to an alarming shortage of effective treatments for resistant microbes, and hence there is a pressing demand for the development of novel antimicrobial interventions. The potential use of antivirulence therapeutics to tackle bacterial infections has attracted considerable attention over the past decades as they hamper the pathogenicity of target microbes with reduced selective pressure, minimizing the emergence of resistance. One such approach is to interfere with the PA pqs quorum sensing system which upon the interaction of PqsR, a Lys-R type transcriptional regulator, with its cognate signal molecules 4-hydroxy-2-heptylquinoline (HHQ) and 2-heptyl-3-hydroxy-4-quinolone (PQS), governs multiple virulence traits and host-microbe interactions. In this study, we report the hit identification and optimization of PqsR antagonists using virtual screening coupled with whole cell assay validation. The optimized hit compound 61 ((R)-2-(4-(3-(6-chloro-4-oxoquinazolin-3(4H)-yl)-2-hydroxypropoxy)phenyl)acetonitrile) was found to inhibit the expression of the PA P-pqsA promoter controlled by PqsR with an IC50 of 1 mu M. Using isothermal titration calorimetry, a K-d of 10 nM for the P-qsR ligand binding domain (PqsR(LBD)) was determined for 61. Furthermore, the crystal structure of 61 with PqsR(LBD) was attained with a resolution of 2.65 angstrom. Compound 61 significantly reduced levels of pyocyanin, PQS, and HHQ in PAO1-L, PA14 lab strains and PAK6085 clinical isolate. Furthermore, this compound potentiated the effect of ciprofloxacin in early stages of biofilm treatment and in Galleria mellonella infected with PA. Altogether, this data shows 61 as a potent PqsR inhibitor with potential for hit to lead optimization toward the identification of a PA QS inhibitor which can be advanced into preclinical development.

AMER CHEMICAL SOC2021

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Physico-chemical aspects of the adhesion and biofilm formation by "Pseudomonas aeruginosa" on unmodified and modified PVC from endotracheal tubes

Karine Triandafillu

EPFL2003

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Pseudomonas entomophila: A Versatile Bacterium with Entomopathogenic Properties

Guennaëlle Dieppois, Bruno Lemaitre, Onya Opota

Pseudomonas entomophila is unique among Pseudomonas species in being able to activate a systemic immune response in both Drosophila larvae and adults. It has been subsequently shown that oral infections with high doses of this bacterium are highly pathogenic to Drosophila and cause massive destruction of the Drosophila gut epithelium. Besides Drosophila, P. entomophila was able to kill other insects from at least three different orders, suggesting that it has a potentially wide host range and making it a promising model for the study of host pathogen interactions and for the development of bio-control agents against insect pests. In order to unravel the features contributing to P. entomophila’s pathogenic properties, its complete genome was sequenced and genetic screens were performed to identify virulence factors encoded by this bacterium. The aim of this chapter is to review the current knowledge we have on this bacterium with a particular focus on the pathogenesis it induces, its virulence effectors and their genetic regulation

Springer2014

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AMER CHEMICAL SOC2021