scholarly journals Enzyme-Mediated Quenching of the Pseudomonas Quinolone Signal (PQS) Promotes Biofilm Formation of Pseudomonas aeruginosa by Increasing Iron Availability

2016 ◽  
Vol 7 ◽  
Author(s):  
Beatrix Tettmann ◽  
Christine Niewerth ◽  
Frank Kirschhöfer ◽  
Anke Neidig ◽  
Andreas Dötsch ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Iron Availability ◽  
Pseudomonas Quinolone Signal

scholarly journals Subinhibitory concentrations of the cationic antimicrobial peptide colistin induce the pseudomonas quinolone signal in Pseudomonas aeruginosa

Microbiology ◽  
2009 ◽  
Vol 155 (9) ◽  
pp. 2826-2837 ◽  
Author(s):  
Joanne Cummins ◽  
F. Jerry Reen ◽  
Christine Baysse ◽  
Marlies J. Mooij ◽  
Fergal O'Gara
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Peptide ◽  
Biofilm Formation ◽  
Bacterial Colonization ◽  
Central Component ◽  
Functional Genomic ◽  
Cationic Antimicrobial Peptide ◽  
Altered Expression ◽  
Pseudomonas Quinolone Signal ◽  
Subinhibitory Concentrations

Colistin is an important cationic antimicrobial peptide (CAMP) in the fight against Pseudomonas aeruginosa infection in cystic fibrosis (CF) lungs. The effects of subinhibitory concentrations of colistin on gene expression in P. aeruginosa were investigated by transcriptome and functional genomic approaches. Analysis revealed altered expression of 30 genes representing a variety of pathways associated with virulence and bacterial colonization in chronic infection. These included response to osmotic stress, motility, and biofilm formation, as well as genes associated with LPS modification and quorum sensing (QS). Most striking was the upregulation of Pseudomonas quinolone signal (PQS) biosynthesis genes, including pqsH, pqsB and pqsE, and the phenazine biosynthesis operon. Induction of this central component of the QS network following exposure to subinhibitory concentrations of colistin may represent a switch to a more robust population, with increased fitness in the competitive environment of the CF lung.

Iron Availability Influences Aggregation, Biofilm, Adhesion and Invasion of Pseudomonas Aeruginosa and Burkholderia Cenocepacia

2005 ◽  
Vol 18 (4) ◽  
pp. 661-670 ◽  
Author(s):  
F. Berlutti ◽  
C. Morea ◽  
A. Battistoni ◽  
S. Sarli ◽  
P. Cipriani ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Iron Concentration ◽  
Burkholderia Cenocepacia ◽  
Iron Availability ◽  
Opportunistic Pathogens ◽  
Free Living ◽  
Healthy Humans ◽  
Systemic Spread ◽  
Epithelial Barriers

Pseudomonas aeruginosa and Burkholderia cenocepacia are predominant opportunistic pathogens in cystic fibrosis (CF) patients. In healthy humans the lower respiratory tract as well as all mucosa, contains a very low free iron concentration (10−18 M), while in CF patients' sputum iron concentration is very high, showing a median value of 63×10−6 M. Accumulation of catalytic reactive iron heavily contributes to subsequent clinical complications in the lung disorders by the production of reactive oxygen species and increases bacterial growth and virulence. The data reported in this study indicate that low iron concentration (Fe3+1 μM) induced free-living forms and motility both in P. aeruginosa and B. cenocepacia, while high iron concentrations (Fe3+ 10 and 100 μM) stimulated aggregation and biofilm formation already in the fluid phases, so demonstrating that aggregation and biofilm formation are positively iron-modulated in these bacteria. Moreover, the different morphological forms (free-living, aggregates and biofilm) showed different capabilities of adhering and invading the bronchial cell line A549. P. aeruginosa PAO1 aggregates, and mostly biofilm, exerted the highest adhesion efficiency, while B. cenocepacia PV1 aggregates or biofilm the lowest. A significant reduction in invasion efficiency by P. aeruginosa biofilm and a significant increase in cell internalization by B. cenocepacia biofilm has been reported. Therefore, the iron availability is an important signal to which P. aeruginosa and B. cenocepacia counteract by leaving the motile free-living forms and entering into a new lifestyle, i.e. biofilm. These data could contribute to explain that the iron-overload of the sputum of CF patients, inducing nonmotile forms, aggregates and biofilm, may facilitate penetration of host epithelial barriers contributing to the establishment of infection, colonization, persistence and systemic spread of these opportunistic pathogens.

scholarly journals Novel intermicrobial molecular interaction: Pseudomonas aeruginosa Quinolone Signal (PQS) modulates Aspergillus fumigatus response to iron

Microbiology ◽  
2020 ◽  
Vol 166 (1) ◽  
pp. 44-55 ◽  
Author(s):  
Hasan Nazik ◽  
Gabriele Sass ◽  
Shajia R. Ansari ◽  
Reyhan Ertekin ◽  
Hubertus Haas ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Aspergillus Fumigatus ◽  
Biofilm Formation ◽  
Fungal Growth ◽  
Wild Type ◽  
Content Type ◽  
Pseudomonas Quinolone Signal ◽  
Maximal Stimulation ◽  
Fe Homeostasis ◽  
Quorum Sensing Molecule

Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af), the commonest bacterium and fungus in compromised host airways, compete for iron (Fe). The Pseudomonas quinolone signal (PQS), a Pa quorum sensing molecule, also chelates Fe, and delivers Fe to the Pa cell membrane using Pa siderophores. In models of Af biofilm formation or preformed biofilms, PQS inhibited Af in a low Fe environment. AfΔsidA (mutant unable to produce siderophores) biofilm was more sensitive to PQS inhibition than wild-type (WT), as was planktonic AfΔsidA growth. PQS decreased WT Af growth on agar. All these inhibitory actions were reversed by Fe. The Pa siderophore pyoverdin, or Af siderophore inhibitor celastrol, act cooperatively with PQS in Af inhibition. These findings all indicate PQS inhibition is owing to Fe chelation. Remarkably, in high Fe environments, PQS enhanced Af biofilm at 1/100 to 1/2000 Fe concentration required for Fe alone to enhance. Planktonic Af growth, and on agar, Af conidiation, were also enhanced by PQS+Fe compared to Fe alone. In contrast, neither AfΔsidA biofilm, nor planktonic AfΔsidA, were enhanced by PQS-Fe compared to Fe. When Af siderophore ferricrocin (FC),+PQS, were added to AfΔsidA, Af was then boosted more than by FC alone. Moreover, FC+PQS+Fe boosted AfΔsidA more than Fe, FC, FC+Fe, PQS+FC or PQS+Fe. Thus PQS-Fe maximal stimulation requires Af siderophores. PQS inhibits Af via chelation under low Fe conditions. In a high Fe environment, PQS paradoxically stimulates Af efficiently, and this involves Af siderophores. PQS production by Pa could stimulate Af in cystic fibrosis airways, where Fe homeostasis is altered and Fe levels increase, supporting fungal growth.

Bioactivity of Phenolic Compounds Extracted from Strawberry against Formation of Pseudomonas aeruginosa Biofilm

2019 ◽  
Vol 10 (01) ◽  
Author(s):  
Baydaa Hussein ◽  
Zainab A. Aldhaher ◽  
Shahrazad Najem Abdu-Allah ◽  
Adel Hamdan
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Phenolic Compounds ◽  
Biofilm Formation ◽  
Opportunistic Infections ◽  
Formation Rate ◽  
Hydrocarbon Chain ◽  
Health Concern ◽  
Gas Chromatography Mass Spectrometry ◽  
Phenolic Contents

Background: Biofilm is a bacterial way of life prevalent in the world of microbes; in addition to that it is a source of alarm in the field of health concern. Pseudomonas aeruginosa is a pathogenic bacterium responsible for all opportunistic infections such as chronic and severe. Aim of this study: This paper aims to provide an overview of the promotion of isolates to produce a biofilm in vitro under special circumstances, to expose certain antibiotics to produce phenotypic evaluation of biofilm bacteria. Methods and Materials: Three diverse ways were used to inhibited biofilm formation of P.aeruginosa by effect of phenolic compounds extracts from strawberries. Isolates produced biofilm on agar MacConkey under certain circumstances. Results: The results showed that all isolates were resistant to antibiotics except sensitive to azithromycin (AZM, 15μg), and in this study was conducted on three ways to detect the biofilm produced, has been detected by the biofilm like Tissue culture plate (TCP), Tube method (TM), Congo Red Agar (CRA). These methods gave a clear result of these isolates under study. Active compounds were analyzed in both extracts by Gas Chromatography-mass Spectrometry which indicate High molecular weight compound with a long hydrocarbon chain. Conclusion: Phenolic compounds could behave as bioactive material and can be useful to be used in pharmaceutical synthesis. Phenolic contents which found in leaves and fruits extracts of strawberries shows antibacterial activity against all strains tested by the ability to reduce the production of biofilm formation rate.

Confocal and SEM imaging to demonstrate food pathogen- biofilm biocontrol by pyocyanin from Pseudomonas aeruginosa BTRY1

2016 ◽  
Vol 6 (01) ◽  
pp. 5218
Author(s):  
Laxmi Mohandas ◽  
Anju T. R. ◽  
Sarita G. Bhat*
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Antibiofilm Activity ◽  
Opportunistic Pathogens ◽  
Redox Active ◽  
Sem Imaging ◽  
The Impact

An assortment of redox-active phenazine compounds like pyocyanin with their characteristic blue-green colour are synthesized by Pseudomonas aeruginosa, Gram-negative opportunistic pathogens, which are also considered one of the most commercially valuable microorganisms. In this study, pyocyanin from Pseudomonas aeruginosa BTRY1 from food sample was assessed for its antibiofilm activity by micro titer plate assay against strong biofilm producers belonging to the genera Bacillus, Staphylococcus, Brevibacterium and Micrococcus. Pyocyanin inhibited biofilm activity in very minute concentrations. This was also confirmed by Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM). Both SEM and CLSM helped to visualize the biocontrol of biofilm formation by eight pathogens. The imaging and quantification by CLSM also established the impact of pyocyanin on biofilm-biocontrol mainly in the food industry.

Sign in / Sign up

Export Citation Format

Share Document