Search results for "pseudomonas"
showing 10 items of 364 documents
Cinnamaldehyde Induces Expression of Efflux Pumps and Multidrug Resistance in Pseudomonas aeruginosa
2019
Essential oils or their components are increasingly used to fight bacterial infections. Cinnamaldehyde (CNA), the main constituent of cinnamon bark oil, has demonstrated interesting properties in vitro against various pathogens, including Pseudomonas aeruginosa. In the present study, we investigated the mechanisms and possible therapeutic consequences of P. aeruginosa adaptation to CNA. Exposure of P. aeruginosa PA14 to subinhibitory concentrations of CNA caused a strong albeit transient increase in the expression of operons that encode the efflux systems MexAB-OprM, MexCD-OprJ, MexEF-OprN, and MexXY/OprM. This multipump activation enhanced from 2- to 8-fold the resistance (MIC) of PA14 to …
The Efflux Pump MexXY/OprM Contributes to the Tolerance and Acquired Resistance of Pseudomonas aeruginosa to Colistin
2020
The intrinsic resistance of Pseudomonas aeruginosa to polymyxins in part relies on the addition of 4-amino-4-deoxy-l-arabinose (Ara4N) molecules to the lipid A of lipopolysaccharide (LPS), through induction of operon arnBCADTEF-ugd (arn) expression. As demonstrated previously, at least three two-component regulatory systems (PmrAB, ParRS, and CprRS) are able to upregulate this operon when bacteria are exposed to colistin. In the present study, gene deletion experiments with the bioluminescent strain PAO1::lux showed that ParRS is a key element in the tolerance of P. aeruginosa to this last-resort antibiotic (i.e., resistance to early drug killing). Other loci of the ParR regulon, such as th…
Spanish Consensus on the Prevention and Treatment of Pseudomonas aeruginosa Bronchial Infections in Cystic Fibrosis Patients
2014
Pseudomonas aeruginosa is the main pathogen in bronchopulmonary infections in cystic fibrosis (CF) patients. It can only be eradicated at early infection stages while reduction of its bacterial load is the therapeutic goal during chronic infection or exacerbations. Neonatal screening and pharmacokinetic/pharmacodynamic knowledge has modified the management of CF-patients. A culture based microbiological follow-up should be performed in patients with no infection with P. aeruginosa. At initial infection, inhaled colistin (0,5-2 MU/tid), tobramycin (300 mg/bid) or aztreonam (75 mg/tid) with or without oral ciprofloxacin (15-20 mg/kg/bid, 2-3 weeks) are recommended. In chronic infections, trea…
A case report of double etiology of ecthyma gangrenosum
2019
Rationale Ecthyma gangrenosum is a cutaneous infection, most commonly occurring during sepsis evolution with Pseudomonas aeruginosa on an immunocompromised background. There have been rare case reports in previously healthy children and rarer are the cases with double etiology. Patient concerns We present the case of a female Caucasian patient, aged 1 year and 8 months, who developed severe sepsis during flu evolution with predominant respiratory and cerebral manifestations. On admission, at skin level, there was noticed a necrotic coccygeal ulceration (with rapid increasing dimensions 0.5/0.5 cm in 24 hours), and with the transformation from a dry necrosis in a sphacelus at the periphery a…
Community-onset Pseudomonas aeruginosa urinary sepsis in elderly people: Predictive factors, adequacy of empirical therapy and outcomes.
2019
Purpose To know the predictive factors for Pseudomonas aeruginosa (PA) urinary sepsis in hospitalised elderly patients coming from community, the adequacy of empirical antibiotic therapy and its outcomes. Methods Retrospective case-control study conducted between 2007 and 2017. Patients aged 65 years or older with PA urinary sepsis were included as cases. Three age-matched controls, with urinary sepsis caused by other microorganisms, were selected for each case. Predictors for PA urinary sepsis were determined by logistic regression analysis. Adequacy of empirical antibiotic therapy and outcomes were compared between both groups. Results A total of 332 patients, from which 83 were cases, we…
Molecular study on nosocomial Pseudomonas aeruginosa strains.
1989
Nosocomial Pseudomonas aeruginosa isolates were typed by DNA fingerprinting techniques. Chromosomal DNA banding patterns, after endonuclease digestion, of six isolates from a neonatal care unit confirmed the results of O-serotyping and antimicrobial susceptibility pattern analysis. In contrast, the characterization by chromosomal DNA fingerprinting of P. aeruginosa strains isolated from patients treated in a burn unit disagreed with the two classic typing methods: in fact, isolates that varied in serotype and antibiograms showed identical restriction endonuclease profiles, whereas two indistinguishable isolates cultured from individual patients were easily and reproducibly differentiated by…
Identification et analyse du rôle de protéines S‐nitrosylées lors de la modulation de la réponse immunitaire d’Arabidopsis thaliana par l’apo-pyoverd…
2019
Des travaux de l’UMR Agroécologie montrent que la réponse immunitaire des plantes est corrélée à leur nutrition en fer et est modulable par la pyoverdine, un sidérophore produit par la souche bactérienne bénéfique Pseudomonas fluorescens C7R12. Le traitement d’Arabidopsis thaliana exposée à une carence en fer par la pyoverdine dépourvue de fer (apo-pyo) restaure en effet la croissance de la plante aux dépens de son immunité. Nous avons émis l’hypothèse que le monoxyde d’azote (NO), une molécule signalétique ubiquitaire, est un acteur de la modulation de la réponse immunitaire des plantes exposées à l’apo-pyo et à sa souche productrice. Afin d’étayer cette hypothèse, trois axes seront dévelo…
Changes of several metabolic parameters of soya inoculated with phytopathogens at application nanochelates
2022
n greenhouse experiments changes in several metabolic parameters soybeans plants after inoculation by P. savastanoi pv. glycinea 9190, X. axonopodis pv. glycines 9192, BCMV, A. laidlawii on background pre-treatment by nanochelates (NHs) of V, Ge, Cu, Mo have been shown. The phenolic compounds content increased in leaves at inoculation by phytopathogens on background pre-treatment by NHs and without it. The content of H2O2 in leaves increased in variants: BCMV (+VNHs, GeNHs, CuNHs), 9192 (+VNHs, CuNHs), 9190 (+GeNHs, CuNHs), A. laidlawii+MoNHs. But it decreased in the variants: BCMV + MoNHs, A. laidlawii + VNHs, 9190 + VNHs, 9192 (+ GeNHs, CuNHs) compared to controls. The peroxidase activity…
Genomic evolution of bacterial populations under co-selection by antibiotics and phage
2017
Bacteria live in dynamic systems where selection pressures can alter rapidly, forcing adaptation to the prevailing conditions. In particular, bacteriophages and antibiotics of anthropogenic origin are major bacterial stressors in many environments. We previously observed that populations of the bacterium Pseudomonas fluorescens SBW25 exposed to the lytic bacteriophage SBW25Φ2 and a noninhibitive concentration of the antibiotic streptomycin (coselection) achieved higher levels of phage resistance compared to populations exposed to the phage alone. In addition, the phage became extinct under coselection while remaining present in the phage alone environment. Further, phenotypic tests indicate…
Overexpression of SAMDC1 gene in Arabidopsis thaliana increases expression of defense-related genes as well as resistance to Pseudomonas syringae and…
2014
It has been previously described that elevation of endogenous spermine levels in Arabidopsis could be achieved by transgenic overexpression of S-Adenosylmethionine decarboxylase (SAMDC) or Spermine synthase (SPMS). In both cases, spermine accumulation had an impact on the plant transcriptome, with up-regulation of a set of genes enriched in functional categories involved in defense-related processes against both biotic and abiotic stresses. In this work, the response of SAMDC1-overexpressing plants against bacterial and oomycete pathogens has been tested. The expression of several pathogen defense-related genes was induced in these plants as well as in wild type plants exposed to an exogeno…