scholarly journals CO2 accelerates Candida albicans biofilm formation and reveals novel approaches to their inhibition on airway management devices

2021 ◽  
Vol 3 (12) ◽  
Author(s):  
Campbell W Gourlay ◽  
Fritz A Muhlschlegel ◽  
Daniel R Pentland
Keyword(s):  
Candida Albicans ◽  
Biofilm Formation ◽  
Environmental Cues ◽  
Exhaled Breath ◽  
Forming Process ◽  
Biofilm Growth ◽  
Human Fungal Pathogen ◽  
Nutritional Immunity ◽  
Significant Extension ◽  
Dimorphic Yeast

C. albicans is the predominant human fungal pathogen worldwide and frequently colonises medical devices, such as voice prosthesis, as a biofilm. It is a dimorphic yeast that can switch between yeast and hyphal forms in response to environmental cues, a property that is essential during biofilm establishment and maturation. One such cue is elevation of CO2 levels, as observed in exhaled breath for example. However, despite the clear medical relevance the effects of high CO2 levels on C. albicans biofilm growth has not been investigated to date. Here, we show that 5% CO2 significantly enhances each stage of the C. albicans biofilm forming process; from attachment through maturation to dispersion, via stimulation of the Ras/cAMP/PKA signalling pathway. Transcriptome analysis of biofilm formation under elevated CO2 conditions revealed the activation of key biofilm formation pathways governed by the central biofilm regulators Efg1, Brg1, Bcr1 and Ndt80. Biofilms grown in under elevated CO2 conditions also exhibit increases in azole resistance, tolerance to nutritional immunity and enhanced glucose uptake capabilities. We thus characterise the mechanisms by which elevated CO2 promote C. albicans biofilm formation. We also investigate the possibility of re-purposing drugs that can target the CO2 activated metabolic enhancements observed in C. albicans biofilms. Using this approach we can significantly reduce multi-species biofilm formation in a high CO2 environment and demonstrate a significant extension of the lifespan of voice prostheses in a patient trial. Our research demonstrates a bench to bedside approach to tackle Candida albicans biofilm formation.

scholarly journals CO2 enhances the ability of Candida albicans to form biofilms, overcome nutritional immunity and resist antifungal treatment

2020 ◽  
Author(s):  
Daniel R. Pentland ◽  
Fritz A. Mühlschlegel ◽  
Campbell W. Gourlay
Keyword(s):  
Fungal Pathogen ◽  
Biofilm Formation ◽  
Environmental Cues ◽  
Exhaled Breath ◽  
Forming Process ◽  
Biofilm Growth ◽  
Nutritional Immunity ◽  
Activated Processes ◽  
Dimorphic Yeast ◽  
Medical Relevance

AbstractC. albicans is the predominant fungal pathogen of humans and frequently colonises medical devices, such as voice prosthesis, as a biofilm. It is a dimorphic yeast that can switch between yeast and hyphal forms in response to environmental cues, a property that is essential during biofilm establishment and maturation. One such cue is the elevation of CO2 levels, as observed in exhaled breath.. However, despite the clear medical relevance, the effects of CO2 on C. albicans biofilm growth has not been investigated to date. Here, we show that physiologically relevant CO2 elevation enhances each stage of the C. albicans biofilm forming process;from attachment through to maturation and dispersion.. The effects of CO2 are mediated via the Ras/cAMP/PKA signalling pathway and the central biofilm regulators Efg1, Brg1, Bcr1 and Ndt80. Biofilms grown under elevated CO2 conditions also exhibit increased azole resistance, tolerance to nutritional immunity and enhanced glucose uptake to support their rapid growth. These findings suggest that C. albicans has evolved to utilise the CO2 signal to promote biofilm formation within the host. We investigate the possibility of targeting CO2 activated processes and propose 2-Deoxyglucose as a drug that may be repurposed to prevent C. albicans biofilm formation on medical airway management implants. We thus characterise the mechanisms by which CO2 promotes C. albicans biofilm formation and suggest new approaches for future preventative strategies.

scholarly journals CO2 enhances the formation, nutrient scavenging and drug resistance properties of C. albicans biofilms

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Daniel R. Pentland ◽  
Jack Davis ◽  
Fritz A. Mühlschlegel ◽  
Campbell W. Gourlay
Keyword(s):  
Fungal Pathogen ◽  
Biofilm Formation ◽  
Environmental Cues ◽  
Exhaled Breath ◽  
Forming Process ◽  
Biofilm Growth ◽  
Human Fungal Pathogen ◽  
Activated Processes ◽  
Dimorphic Yeast ◽  
Medical Relevance

AbstractC. albicans is the predominant human fungal pathogen and frequently colonises medical devices, such as voice prostheses, as a biofilm. It is a dimorphic yeast that can switch between yeast and hyphal forms in response to environmental cues, a property that is essential during biofilm establishment and maturation. One such cue is the elevation of CO2 levels, as observed in exhaled breath for example. However, despite the clear medical relevance, the effect of CO2 on C. albicans biofilm growth has not been investigated to date. Here we show that physiologically relevant CO2 elevation enhances each stage of the C. albicans biofilm-forming process: from attachment through maturation to dispersion. The effects of CO2 are mediated via the Ras/cAMP/PKA signalling pathway and the central biofilm regulators Efg1, Brg1, Bcr1 and Ndt80. Biofilms grown under elevated CO2 conditions also exhibit increased azole resistance, increased Sef1-dependent iron scavenging and enhanced glucose uptake to support their rapid growth. These findings suggest that C. albicans has evolved to utilise the CO2 signal to promote biofilm formation within the host. We investigate the possibility of targeting CO2-activated processes and propose 2-deoxyglucose as a drug that may be repurposed to prevent C. albicans biofilm formation on medical airway management implants. We thus characterise the mechanisms by which CO2 promotes C. albicans biofilm formation and suggest new approaches for future preventative strategies.

scholarly journals A modified crystal violet assay is comparable to XTT reduction assay for quantification of biofilm formation by Candida albicans

2020 ◽  
Author(s):  
Yue Qu ◽  
Shoufeng Yang ◽  
Zhangzhang Chen ◽  
Feifei Su
Keyword(s):  
Candida Albicans ◽  
Crystal Violet ◽  
Biofilm Formation ◽  
Quantitative Methods ◽  
Standard Procedure ◽  
Short Term ◽  
Biofilm Growth ◽  
Human Fungal Pathogen ◽  
Crystal Violet Assay ◽  
Reduction Assay

Abstract Background: The ability of the human fungal pathogen Candida albicans to form biofilms, for example on indwelling medical devices, is a major pathogenic mechanism and has been the focus of intense studies in the fungal pathogenesis field. A key research tool used is the quantitative methods for measuring biofilm formation of C. albicans. Objective: We sought to optimize the conventional crystal violet (CV) staining assay for quantification of biofilm formation by C. albicans and evaluate its performance. Methods: Individual modifications included (i) submerge-washing of microplates to remove non-adherent cells, (ii) heat-fixation, (iii) short-term staining for 3 min, (iv) submerge-washing to remove unbound CV dye, and (v) short-term destaining for 15 min were compared with the standard procedure, and those were superior were incorporated. Performance analysis was carried out for the modified CV assay, in comparison to the conventional CV assay and the XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide] reduction assay. Results: The modified CV assay demonstrated several advantages in quantitative assessment of biofilm formation of C. albicans over the conventional CV assay, including greater accuracy and reproducibility, shorter experimental time and reduced labor intensity, and was at least comparable to the XTT reduction assay.Conclusion: The modified CV method can be used as an alternative to the XTT reduction assay in quantification of biofilm growth by C. albicans.

Hormones modulate Candida vaginal isolates biofilm formation and decrease their susceptibility to azoles and hydrogen peroxide

2019 ◽  
Vol 58 (3) ◽  
pp. 341-350
Author(s):  
Bruna Gonçalves ◽  
Nuno Miguel Azevedo ◽  
Mariana Henriques ◽  
Sónia Silva
Keyword(s):  
Hydrogen Peroxide ◽  
Candida Albicans ◽  
Biofilm Formation ◽  
Candida Glabrata ◽  
The Other ◽  
Environmental Cues ◽  
Intrauterine Devices ◽  
Normal Cycle ◽  
Acidic Conditions ◽  
High Adaptation

Abstract Vulvovaginal candidiasis (VVC) is an infection usually caused by Candida albicans and increasingly by Candida glabrata, which has an intrinsically high resistance to commonly used antifungals. Candida species possess virulence factors that contribute to VVC development, as the ability to form biofilms in vaginal walls and intrauterine devices. It is known that VVC is promoted by conditions that increase the hormones levels, during pregnancy, however, the effects of hormones on Candida cells are poorly studied, especially in C. glabrata. Thus, the influence of progesterone and β-estradiol, at normal cycle and pregnancy concentrations, on biofilm formation and resistance of C. albicans and C. glabrata vaginal isolates, was analyzed using acidic conditions (pH 4). Biofilms of C. albicans developed in the presence of hormones presented reduced biomass (up to 65%) and impaired cells ability to produce filamentous forms. On the other hand, C. glabrata presented high adaptation to the presence of hormones, which did not affect its biofilm formation. Additionally, hormones impaired the susceptibility of C. albicans and C. glabrata cells to azoles, with potential clinical significance in the presence of pregnancy hormone levels. A similar result was obtained for the susceptibility to hydrogen peroxide, a biological vaginal barrier against Candida growth. Overall, the results of this study suggest that hormones may act as environmental cues promoting Candida protection from vaginal defenses and harmful conditions, what may have implications in Candida vaginal pathogenicity and treatment of VVC, especially in C. glabrata infections due to its high adaptability to vaginal conditions.

scholarly journals Improvement of XTT assay performance for studies involving Candida albicans biofilms

2008 ◽  
Vol 19 (4) ◽  
pp. 364-369 ◽  
Author(s):  
Wander José da Silva ◽  
Jayampath Seneviratne ◽  
Nipuna Parahitiyawa ◽  
Edvaldo Antonio Ribeiro Rosa ◽  
Lakshman Perera Samaranayake ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Biofilm Formation ◽  
Cell Activity ◽  
Growth Yield ◽  
Xtt Assay ◽  
Biofilm Growth ◽  
Assay Performance ◽  
Reduction Assay ◽  
Cell Layers ◽  
Biofilm Development

2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction assay has been used to study Candida biofilm formation. However, considering that the XTT reduction assay is dependent on cell activity, its use for evaluating mature biofilms may lead to inaccuracies since biofilm bottom cell layers tend to be relatively quiescent at later stages of biofilm formation. The aim of this study was to improve XTT reduction assay by adding glucose supplements to the standard XTT formulation. Candida albicans ATCC 90028 was used to form 24-, 48- and 72-h biofilms. The oxidative activity at 90, 180 and 270 min of incubation was evaluated. The control consisted of standard XTT formulation without glucose supplements, and was modified by the addition of 50, 100 and 200 mM of glucose. The XTT assay with 200 mM glucose showed more accurate and consistent readings correlating with biofilm development at 24, 48 and 72 h. Biofilm growth yield after 180 min incubation, when evaluated with the 200 mM glucose supplemented XTT, produced the most consistent readings on repetitive testing. It may be concluded that glucose supplementation of XTT could minimize variation and produce more accurate data for the XTT assay.

scholarly journals Simple Carbohydrate Derivatives Diminish the Formation of Biofilm of the Pathogenic Yeast Candida albicans

Antibiotics ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 10 ◽  
Author(s):  
Olena P. Ishchuk ◽  
Olov Sterner ◽  
Ulf Ellervik ◽  
Sophie Manner
Keyword(s):  
Candida Albicans ◽  
Fungal Pathogen ◽  
Biofilm Formation ◽  
Untreated Control ◽  
Morphological Transition ◽  
Pathogenic Yeast ◽  
Yeast Form ◽  
Human Fungal Pathogen ◽  
Morphological Transitions ◽  
Simple Carbohydrate

The opportunistic human fungal pathogen Candida albicans relies on cell morphological transitions to develop biofilm and invade the host. In the current study, we developed new regulatory molecules, which inhibit the morphological transition of C. albicans from yeast-form cells to cells forming hyphae. These compounds, benzyl α-l-fucopyranoside and benzyl β-d-xylopyranoside, inhibit the hyphae formation and adhesion of C. albicans to a polystyrene surface, resulting in a reduced biofilm formation. The addition of cAMP to cells treated with α-l-fucopyranoside restored the yeast-hyphae switch and the biofilm level to that of the untreated control. In the β-d-xylopyranoside treated cells, the biofilm level was only partially restored by the addition of cAMP, and these cells remained mainly as yeast-form cells.

scholarly journals Disparate Candida albicans Biofilm Formation in Clinical Lipid Emulsions Due to Capric Acid-Mediated Inhibition

2019 ◽  
Vol 63 (11) ◽  
Author(s):  
Hubertine M. E. Willems ◽  
Jeremy S. Stultz ◽  
Molly E. Coltrane ◽  
Jabez P. Fortwendel ◽  
Brian M. Peters
Keyword(s):  
Candida Albicans ◽  
Biofilm Formation ◽  
Bloodstream Infections ◽  
Capric Acid ◽  
Lipid Emulsions ◽  
Biofilm Growth ◽  
Content Type ◽  
Biofilm Model ◽  
Hypha Formation

ABSTRACT Receipt of parenteral nutrition (PN) remains an independent risk factor for developing catheter-related bloodstream infections (CR-BSI) caused by fungi, including by the polymorphic fungus Candida albicans, which is notoriously adept at forming drug-resistant biofilm structures. Among a variety of macronutrients, PN solutions contain lipid emulsions to supply daily essential fats and are often delivered via central venous catheters (CVCs). Therefore, using an in vitro biofilm model system, we sought to determine whether various clinical lipid emulsions differentially impacted biofilm growth in C. albicans. We observed that the lipid emulsions Intralipid and Omegaven both stimulated C. albicans biofilm formation during growth in minimal medium or a macronutrient PN solution. Conversely, Smoflipid inhibited C. albicans biofilm formation by approximately 50%. Follow-up studies revealed that while Smoflipid did not impair C. albicans growth, it did significantly inhibit hypha formation and hyphal elongation. Moreover, growth inhibition could be recapitulated in Intralipid when supplemented with capric acid—a fatty acid present in Smoflipid but absent in Intralipid. Capric acid was also found to dose dependently inhibit C. albicans biofilm formation in PN solutions. This is the first study to directly compare different clinical lipid emulsions for their capacity to affect C. albicans biofilm growth. Results derived from this study necessitate further research regarding different lipid emulsions and rates of fungus-associated CR-BSIs.

scholarly journals Adhesion and biofilm formation of Candida albicans on native and Pluronic-treated polystyrene

Biofilms ◽  
2005 ◽  
Vol 2 (1) ◽  
pp. 63-71 ◽  
Author(s):  
K. E. Wesenberg-Ward ◽  
B. J. Tyler ◽  
J. T. Sears
Keyword(s):  
Candida Albicans ◽  
Biofilm Formation ◽  
Pluronic F127 ◽  
Artificial Organs ◽  
Confocal Scanning Laser Microscopy ◽  
Mechanical Trauma ◽  
Biofilm Growth ◽  
Prosthetic Devices ◽  
Initial Adhesion ◽  
Defined Culture

Candida albicans forms part of the normal human flora whose growth is usually restricted by the normal flora bacteria and the host's immune system. It is an opportunistic fungal pathogen that causes infections in immunocompromised individuals, mechanical trauma victims and iatrogenic patients. Candida albicans can ingress the human host by adhering to a plastic surface (i.e. prosthetic devices, catheters, artificial organs, etc.) that is subsequently implanted, and forms a protective biofilm that provides a continuous reservoir of yeast to be hematogenously dispersed. In order for the medical profession to battle device-related infections, initial adhesion and biofilm formation of C. albicans needs to be better understood. There has been some skepticism as to whether the initial adhesion events bear any relationship to subsequent biofilm formation. Thus, to better comprehend the relationship between the initial adhesion rates and growth rate and biofilm formation, these events were studied on two different, well-defined culture surfaces, native polystyrene and Pluronic F127-conditioned polystyrene. The adhesion studies determined that Pluronic F127 adsorption dramatically reduced the adhesion of C. albicans to polystyrene. The biofilm growth studies, analyzed by confocal scanning laser microscopy, revealed that Pluronic F127 decreased the biofilm surface coverage, cluster group size, thickness and the presence of hyphal elements over the untreated polystyrene. These findings indicate that the effect of a material's surface chemistry on the initial adhesion process has a direct influence on subsequent biofilm formation.

scholarly journals Carnitine-Dependent Transport of Acetyl Coenzyme A in Candida albicans Is Essential for Growth on Nonfermentable Carbon Sources and Contributes to Biofilm Formation

2008 ◽  
Vol 7 (4) ◽  
pp. 610-618 ◽  
Author(s):  
Karin Strijbis ◽  
Carlo W. T. van Roermund ◽  
Wouter F. Visser ◽  
Els C. Mol ◽  
Janny van den Burg ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Fatty Acid ◽  
Fungal Pathogen ◽  
Biofilm Formation ◽  
Carbon Sources ◽  
Acetyl Coa ◽  
Oxidation Activity ◽  
Acetyl Coenzyme A ◽  
Human Fungal Pathogen ◽  
Peroxisomal Fatty Acid

ABSTRACT In eukaryotes, acetyl coenzyme A (acetyl-CoA) produced during peroxisomal fatty acid β-oxidation needs to be transported to mitochondria for further metabolism. Two parallel pathways for acetyl-CoA transport have been identified in Saccharomyces cerevisiae; one is dependent on peroxisomal citrate synthase (Cit), while the other requires peroxisomal and mitochondrial carnitine acetyltransferase (Cat) activities. Here we show that the human fungal pathogen Candida albicans lacks peroxisomal Cit, relying exclusively on Cat activity for transport of acetyl units. Deletion of the CAT2 gene encoding the major Cat enzyme in C. albicans resulted in a strain that had lost both peroxisomal and mitochondrion-associated Cat activities, could not grow on fatty acids or C2 carbon sources (acetate or ethanol), accumulated intracellular acetyl-CoA, and showed greatly reduced fatty acid β-oxidation activity. The cat2 null mutant was, however, not attenuated in virulence in a mouse model of systemic candidiasis. These observations support our previous results showing that peroxisomal fatty acid β-oxidation activity is not essential for C. albicans virulence. Biofilm formation by the cat2 mutant on glucose was slightly reduced compared to that by the wild type, although both strains grew at the same rate on this carbon source. Our data show that C. albicans has diverged considerably from S. cerevisiae with respect to the mechanism of intracellular acetyl-CoA transport and imply that carnitine dependence may be an important trait of this human fungal pathogen.

scholarly journals Growth Competition between Candida dubliniensis and Candida albicans under Broth and Biofilm Growing Conditions

2000 ◽  
Vol 38 (2) ◽  
pp. 902-904 ◽  
Author(s):  
W. R. Kirkpatrick ◽  
J. L. Lopez-Ribot ◽  
R. K. Mcatee ◽  
T. F. Patterson
Keyword(s):  
Candida Albicans ◽  
Competitive Advantage ◽  
Biofilm Formation ◽  
Competitive Interaction ◽  
Candida Dubliniensis ◽  
Broth Culture ◽  
Species Differentiation ◽  
Biofilm Growth ◽  
Supporting Structure ◽  
Growing Conditions

Seven isolates each of Candida albicans andCandida dubliniensis were paired (11 pairs) and examined for competitive interaction. Equal numbers of CFU of each competitor were inoculated into Sabouraud dextrose broth and incubated at 37°C with vigorous shaking under conditions favorable to either broth or biofilm growth. Surviving proportions of each competitor were calculated from the broth culture at 24 and 96 h and the biofilm culture at 96 h, with species differentiation done on CHROMagar Candida medium. C. albicans had a competitive advantage over C. dubliniensis in broth culture and under biofilm growing conditions; however, with the presence of a supporting structure for biofilm formation, C. dubliniensis was able to better withstand the competitive pressures from C. albicans.

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