In VitroAnalyses of the Effects of Heparin and Parabens on Candida albicans Biofilms and Planktonic Cells

ABSTRACTInfections and thromboses are the most common complications associated with central venous catheters. Suggested strategies for prevention and management of these complications include the use of heparin-coated catheters, heparin locks, and antimicrobial lock therapy. However, the effects of heparin onCandida albicansbiofilms and planktonic cells have not been previously studied. Therefore, we sought to determine thein vitroeffect of a heparin sodium preparation (HP) on biofilms and planktonic cells ofC. albicans. Because HP contains two preservatives, methyl paraben (MP) and propyl paraben (PP), these compounds and heparin sodium without preservatives (Pure-H) were also tested individually. The metabolic activity of the mature biofilm after treatment was assessed using XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction and microscopy. Pure-H, MP, and PP caused up to 75, 85, and 60% reductions of metabolic activity of the mature preformedC. albicansbiofilms, respectively. Maximal efficacy against the mature biofilm was observed with HP (up to 90%) compared to the individual compounds (P< 0.0001). Pure-H, MP, and PP each inhibitedC. albicansbiofilm formation up to 90%. A complete inhibition of biofilm formation was observed with HP at 5,000 U/ml and higher. When tested against planktonic cells, each compound inhibited growth in a dose-dependent manner. These data indicated that HP, MP, PP, and Pure-H havein vitroantifungal activity againstC. albicansmature biofilms, formation of biofilms, and planktonic cells. Investigation of high-dose heparin-based strategies (e.g., heparin locks) in combination with traditional antifungal agents for the treatment and/or prevention ofC. albicansbiofilms is warranted.

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Quinacrine Inhibits Candida albicans Growth and Filamentation at Neutral pH

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.03083-14 ◽

2014 ◽

Vol 58 (12) ◽

pp. 7501-7509 ◽

Cited By ~ 14

Author(s):

Vibhati V. Kulkarny ◽

Alba Chavez-Dozal ◽

Hallie S. Rane ◽

Maximillian Jahng ◽

Stella M. Bernardo ◽

...

Keyword(s):

Candida Albicans ◽

Bloodstream Infections ◽

High Dose ◽

Antibiofilm Activity ◽

Dependent Manner ◽

Xtt Assay ◽

Content Type ◽

Prevention And Treatment ◽

Ph Dependent

ABSTRACTCandida albicansis a common cause of catheter-related bloodstream infections (CR-BSI), in part due to its strong propensity to form biofilms. Drug repurposing is an approach that might identify agents that are able to overcome antifungal drug resistance within biofilms. Quinacrine (QNC) is clinically active against the eukaryotic protozoan parasitesPlasmodiumandGiardia. We sought to investigate the antifungal activity of QNC againstC. albicansbiofilms.C. albicansbiofilms were incubated with QNC at serially increasing concentrations (4 to 2,048 μg/ml) and assessed using a 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay in a static microplate model. Combinations of QNC and standard antifungals were assayed using biofilm checkerboard analyses. To define a mechanism of action, QNC was assessed for the inhibition of filamentation, effects on endocytosis, and pH-dependent activity. High-dose QNC was effective for the prevention and treatment ofC. albicansbiofilmsin vitro. QNC with fluconazole had no interaction, while the combination of QNC and either caspofungin or amphotericin B demonstrated synergy. QNC was most active against planktonic growth at alkaline pH. QNC dramatically inhibited filamentation. QNC accumulated within vacuoles as expected and caused defects in endocytosis. A tetracycline-regulatedVMA3mutant lacking vacuolar ATPase (V-ATPase) function demonstrated increased susceptibility to QNC. These experiments indicate that QNC is active againstC. albicansgrowth in a pH-dependent manner. Although QNC activity is not biofilm specific, QNC is effective in the prevention and treatment of biofilms. QNC antibiofilm activity likely occurs via several independent mechanisms: vacuolar alkalinization, inhibition of endocytosis, and impaired filamentation. Further investigation of QNC for the treatment and prevention of biofilm-relatedCandidaCR-BSI is warranted.

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Eap1p, an Adhesin That Mediates Candida albicans Biofilm Formation In Vitro and In Vivo

Eukaryotic Cell ◽

10.1128/ec.00049-07 ◽

2007 ◽

Vol 6 (6) ◽

pp. 931-939 ◽

Cited By ~ 96

Author(s):

Fang Li ◽

Michael J. Svarovsky ◽

Amy J. Karlsson ◽

Joel P. Wagner ◽

Karen Marchillo ◽

...

Keyword(s):

Candida Albicans ◽

Cell Adhesion ◽

Biofilm Formation ◽

Fungal Infections ◽

Gene Dosage ◽

Venous Catheter ◽

Flow Chamber ◽

Dependent Manner

ABSTRACT Candida albicans is the leading cause of systemic fungal infections in immunocompromised humans. The ability to form biofilms on surfaces in the host or on implanted medical devices enhances C. albicans virulence, leading to antimicrobial resistance and providing a reservoir for infection. Biofilm formation is a complex multicellular process consisting of cell adhesion, cell growth, morphogenic switching between yeast form and filamentous states, and quorum sensing. Here we describe the role of the C. albicans EAP1 gene, which encodes a glycosylphosphatidylinositol-anchored, glucan-cross-linked cell wall protein, in adhesion and biofilm formation in vitro and in vivo. Deleting EAP1 reduced cell adhesion to polystyrene and epithelial cells in a gene dosage-dependent manner. Furthermore, EAP1 expression was required for C. albicans biofilm formation in an in vitro parallel plate flow chamber model and in an in vivo rat central venous catheter model. EAP1 expression was upregulated in biofilm-associated cells in vitro and in vivo. Our results illustrate an association between Eap1p-mediated adhesion and biofilm formation in vitro and in vivo.

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

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01394-19 ◽

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.

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Targeting Fibronectin To Disrupt In Vivo Candida albicans Biofilms

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.03094-15 ◽

2016 ◽

Vol 60 (5) ◽

pp. 3152-3155 ◽

Cited By ~ 7

Author(s):

Jeniel E. Nett ◽

Jonathan Cabezas-Olcoz ◽

Karen Marchillo ◽

Deane F. Mosher ◽

David R. Andes

Keyword(s):

Candida Albicans ◽

Biofilm Formation ◽

Drug Targets ◽

Venous Catheter ◽

Surface Adhesion ◽

Inhibitory Protein ◽

Content Type ◽

Novel Target

ABSTRACTNew drug targets are of great interest for the treatment of fungal biofilms, which are routinely resistant to antifungal therapies. We theorized that the interaction ofCandida albicanswith matricellular host proteins would provide a novel target. Here, we show that an inhibitory protein (FUD) targetingCandida-fibronectin interactions disrupts biofilm formationin vitroandin vivoin a rat venous catheter model. The peptide appears to act by blocking the surface adhesion ofCandida, halting biofilm formation.

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Oral Administration of the Broad-Spectrum Antibiofilm Compound Toremifene Inhibits Candida albicans and Staphylococcus aureus Biofilm FormationIn Vivo

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.03869-14 ◽

2014 ◽

Vol 58 (12) ◽

pp. 7606-7610 ◽

Cited By ~ 16

Author(s):

Kaat De Cremer ◽

Nicolas Delattin ◽

Katrijn De Brucker ◽

Annelies Peeters ◽

Soña Kucharíková ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Candida Albicans ◽

Broad Spectrum ◽

Staphylococcus Epidermidis ◽

Biofilm Formation ◽

Candida Krusei ◽

Content Type ◽

And Staphylococcus Aureus

ABSTRACTWe here report on thein vitroactivity of toremifene to inhibit biofilm formation of different fungal and bacterial pathogens, includingCandida albicans,Candida glabrata,Candida dubliniensis,Candida krusei,Pseudomonas aeruginosa,Staphylococcus aureus, andStaphylococcus epidermidis. We validated thein vivoefficacy of orally administered toremifene againstC. albicans and S. aureusbiofilm formation in a rat subcutaneous catheter model. Combined, our results demonstrate the potential of toremifene as a broad-spectrum oral antibiofilm compound.

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VpsR Directly Activates Transcription of Multiple Biofilm Genes in Vibrio cholerae

Journal of Bacteriology ◽

10.1128/jb.00234-20 ◽

2020 ◽

Vol 202 (18) ◽

Cited By ~ 2

Author(s):

Meng-Lun Hsieh ◽

Christopher M. Waters ◽

Deborah M. Hinton

Keyword(s):

Rna Polymerase ◽

Vibrio Cholerae ◽

Biofilm Formation ◽

Core Promoter ◽

Class Ii ◽

Class I ◽

Dependent Manner ◽

Mobility Shift ◽

Content Type

ABSTRACT Vibrio cholerae biofilm biogenesis, which is important for survival, dissemination, and persistence, requires multiple genes in the Vibrio polysaccharides (vps) operons I and II as well as the cluster of ribomatrix (rbm) genes. Transcriptional control of these genes is a complex process that requires several activators/repressors and the ubiquitous signaling molecule, cyclic di-GMP (c-di-GMP). Previously, we demonstrated that VpsR directly activates RNA polymerase containing σ70 (σ70-RNAP) at the vpsL promoter (PvpsL), which precedes the vps-II operon, in a c-di-GMP-dependent manner by stimulating formation of the transcriptionally active, open complex. Using in vitro transcription, electrophoretic mobility shift assays, and DNase I footprinting, we show here that VpsR also directly activates σ70-RNAP transcription from other promoters within the biofilm formation cluster, including PvpsU, at the beginning of the vps-I operon, PrbmA, at the start of the rbm cluster, and PrbmF, which lies upstream of the divergent rbmF and rbmE genes. In this capacity, we find that VpsR is able to behave both as a class II activator, which functions immediately adjacent/overlapping the core promoter sequence (PvpsL and PvpsU), and as a class I activator, which functions farther upstream (PrbmA and PrbmF). Because these promoters vary in VpsR-DNA binding affinity in the absence and presence of c-di-GMP, we speculate that VpsR’s mechanism of activation is dependent on both the concentration of VpsR and the level of c-di-GMP to increase transcription, resulting in finely tuned regulation. IMPORTANCE Vibrio cholerae, the bacterial pathogen that is responsible for the disease cholera, uses biofilms to aid in survival, dissemination, and persistence. VpsR, which directly senses the second messenger c-di-GMP, is a major regulator of this process. Together with c-di-GMP, VpsR directly activates transcription by RNA polymerase containing σ70 from the vpsL biofilm biogenesis promoter. Using biochemical methods, we demonstrate for the first time that VpsR/c-di-GMP directly activates σ70-RNA polymerase at the first genes of the vps and ribomatrix operons. In this regard, it functions as either a class I or class II activator. Our results broaden the mechanism of c-di-GMP-dependent transcription activation and the specific role of VpsR in biofilm formation.

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The Transcriptional Regulator Nrg1p Controls Candida albicans Biofilm Formation and Dispersion

Eukaryotic Cell ◽

10.1128/ec.00111-10 ◽

2010 ◽

Vol 9 (10) ◽

pp. 1531-1537 ◽

Cited By ~ 59

Author(s):

Priya Uppuluri ◽

Christopher G. Pierce ◽

Derek P. Thomas ◽

Sarah S. Bubeck ◽

Stephen P. Saville ◽

...

Keyword(s):

Candida Albicans ◽

Biofilm Formation ◽

Structural Integrity ◽

Genetically Engineered ◽

Negative Regulator ◽

Yeast Cells ◽

Developmental Cycle ◽

Content Type ◽

Adhesive Interactions

ABSTRACT The ability of Candida albicans to reversibly switch morphologies is important for biofilm formation and dispersion. In this pathogen, Nrg1p functions as a key negative regulator of the yeast-to-hypha morphogenetic transition. We have previously described a genetically engineered C. albicans tet-NRG1 strain in which NRG1 expression levels can be manipulated by the presence or absence of doxycycline (DOX). Here, we have used this strain to ascertain the role of Nrg1p in regulating the different stages of the C. albicans biofilm developmental cycle. In an in vitro model of biofilm formation, the C. albicans tet-NRG1 strain was able to form mature biofilms only when DOX was present in the medium, but not in the absence of DOX, when high levels of NRG1 expression blocked the yeast-to-hypha transition. However, in a biofilm cell retention assay in which biofilms were developed with mixtures of C. albicans tet-NRG1 and SC5314 strains, tet-NRG1 yeast cells were still incorporated into the mixed biofilms, in which an intricate network of hyphae of the wild-type strain provided for biofilm structural integrity and adhesive interactions. Also, utilizing an in vitro biofilm model under conditions of flow, we demonstrated that C. albicans Nrg1p exerts an exquisite control of the dispersal process, as overexpression of NRG1 leads to increases in dispersion of yeast cells from the biofilms. Our results demonstrate that manipulation of NRG1 gene expression has a profound influence on biofilm formation and biofilm dispersal, thus identifying Nrg1p as a key regulator of the C. albicans biofilm life cycle.

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The Heat-Induced Molecular Disaggregase Hsp104 of Candida albicans Plays a Role in Biofilm Formation and Pathogenicity in a Worm Infection Model

Eukaryotic Cell ◽

10.1128/ec.00147-12 ◽

2012 ◽

Vol 11 (8) ◽

pp. 1012-1020 ◽

Cited By ~ 17

Author(s):

Alessandro Fiori ◽

Soňa Kucharíková ◽

Gilmer Govaert ◽

Bruno P. A. Cammue ◽

Karin Thevissen ◽

...

Keyword(s):

Candida Albicans ◽

Stress Responses ◽

Biofilm Formation ◽

Fungal Pathogens ◽

Elevated Temperatures ◽

Structural Defects ◽

Infection Model ◽

Content Type

ABSTRACT The consequences of deprivation of the molecular chaperone Hsp104 in the fungal pathogen Candida albicans were investigated. Mutants lacking HSP104 became hypersusceptible to lethally high temperatures, similarly to the corresponding mutants of Saccharomyces cerevisiae , whereas normal susceptibility was restored upon reintroduction of the gene. By use of a strain whose only copy of HSP104 is an ectopic gene under the control of a tetracycline-regulated promoter, expression of Hsp104 prior to the administration of heat shock could be demonstrated to be sufficient to confer protection from the subsequent temperature increase. This result points to a key role for Hsp104 in orchestrating the cell response to elevated temperatures. Despite their not showing evident growth or morphological defects, biofilm formation by cells lacking HSP104 proved to be defective in two established in vitro models that use polystyrene and polyurethane as the substrates. Biofilms formed by the wild-type and HSP104 -reconstituted strains showed patterns of intertwined hyphae in the extracellular matrix. In contrast, biofilm formed by the hsp104 Δ/ hsp104 Δ mutant showed structural defects and appeared patchy and loose. Decreased virulence of the hsp104 Δ/ hsp104 Δ mutant was observed in the Caenorhabditis elegans infection model, in which high in vivo temperature does not play a role. In agreement with the view that stress responses in fungal pathogens may have evolved to provide niche-specific adaptation to environmental conditions, these results provide an indication of a temperature-independent role for Hsp104 in support of Candida albicans virulence, in addition to its key role in governing thermotolerance.

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In VitroInteractions between Aspirin and Amphotericin B against Planktonic Cells and Biofilm Cells of Candida albicans and C. parapsilosis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.06082-11 ◽

2012 ◽

Vol 56 (6) ◽

pp. 3250-3260 ◽

Cited By ~ 43

Author(s):

Yabin Zhou ◽

Ganggang Wang ◽

Yutang Li ◽

Yang Liu ◽

Yu Song ◽

...

Keyword(s):

Candida Albicans ◽

Amphotericin B ◽

Antimicrobial Agents ◽

Positive Interactions ◽

Antibiofilm Activity ◽

Data Generation ◽

Planktonic Cells ◽

Content Type ◽

Time Kill

ABSTRACTThe increase in drug resistance and invasion caused by biofilm formation brings enormous challenges to the management ofCandidainfection. Aspirin's antibiofilm activityin vitrowas discovered recently. The spectrophotometric method and the XTT {2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide} reduction assay used for data generation make it possible to evaluate fungal biofilm growth accurately. The combined use of the most commonly used methods, the fractional inhibitory concentration index (FICI) and a newly developed method, the ΔEmodel, which uses the concentration-effect relationship over the whole concentration range instead of using the MIC index alone, makes the interpretation of results more reliable. As an attractive tool for studying the pharmacodynamics of antimicrobial agents, time-kill curves can provide detailed information about antimicrobial efficacy as a function of both time and concentration. In the present study,in vitrointeractions between aspirin (acetylsalicylic acid [ASA]) and amphotericin B (AMB) against planktonic cells and biofilm cells ofCandida albicansandC. parapsilosiswere evaluated by the checkerboard microdilution method and the time-kill test. Synergistic and indifferent effects were found for the combination of ASA and AMB against planktonic cells, while strong synergy was found against biofilm cells analyzed by FICI. The ΔEmodel gave more consistent results with FICI. The positive interactions in concentration were also confirmed by the time-kill test. Moreover, this approach also revealed the pharmacodynamics changes of ASA and synergistic action on time. Our findings suggest a potential clinical use for combination therapy with ASA and AMB to augment activity against biofilm-associated infections.

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The Candida albicans ATO Gene Family Promotes Neutralization of the Macrophage Phagolysosome

Infection and Immunity ◽

10.1128/iai.00984-15 ◽

2015 ◽

Vol 83 (11) ◽

pp. 4416-4426 ◽

Cited By ~ 30

Author(s):

Heather A. Danhof ◽

Michael C. Lorenz

Keyword(s):

Amino Acids ◽

Candida Albicans ◽

Hyphal Growth ◽

Dominant Negative ◽

Dependent Manner ◽

Ph Change ◽

Content Type ◽

Ammonia Release ◽

Hyphal Formation

ABSTRACTCandida albicansis an opportunistic human fungal pathogen that causes a variety of diseases, ranging from superficial mucosal to life-threatening systemic infections, the latter particularly in patients with defects in innate immune function.C. albicanscells phagocytosed by macrophages undergo a dramatic change in their metabolism in which amino acids are a key nutrient. We have shown that amino acid catabolism allows the cell to neutralize the phagolysosome and initiate hyphal growth. We show here that members of the 10-geneATOfamily, which are induced by phagocytosis or the presence of amino acids in an Stp2-dependent manner and encode putative acetate or ammonia transporters, are important effectors of this pH changein vitroand in macrophages. When grown with amino acids as the sole carbon source, the deletion ofATO5or the expression of a dominant-negativeATO1G53Dallele results in a delay in alkalinization, a defect in hyphal formation, and a reduction in the amount of ammonia released from the cell. These strains also form fewer hyphae after phagocytosis, have a reduced ability to escape macrophages, and reside in more acidic phagolysosomal compartments than wild-type cells. Furthermore, overexpression of many of the 10ATOgenes accelerates ammonia release, and anato5Δ ATO1G53Ddouble mutant strain has additive alkalinization and ammonia release defects. Taken together, these results indicate that the Ato protein family is a key mediator of the metabolic changes that allowC. albicansto overcome the macrophage innate immunity barrier.

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