Lichen Polyphenolic Compounds for the Eradication of Candida albicans Biofilms

Lichens, due to their symbiotic nature (association between fungi and algae), constitute a chemical factory of original compounds. Polyphenolic compounds (depsides and depsidones) are the main constituents of lichens and are exclusively biosynthesized by these organisms. A panel of 11 polyphenols was evaluated for their anti-biofilm activity against Candida albicans biofilms on the maturation phase (anti-maturation) (MMIC50) as well as on preformed 24-h-old biofilm (anti-biofilm) (MBIC50) using the XTT assay. Minimum inhibitory concentrations of compounds (MICs) against C. albicans planktonic yeast were also determined using a broth microdilution method. While none of the tested compounds were active against planktonic cells (IC50 > 100 µg/ml), three depsides slowed the biofilm maturation (MMIC50 ≤12.5 µg/ml after 48 h of contact with Candida cells). Evernic acid was able to both slow the maturation and reduce the already formed biofilms with MBIC50 ≤12.5 µg/ml after 48 h of contact with the biofilm. This compound shows a weak toxicity against HeLa cells (22%) at the minimal active concentration and no hemolytic activity at 100 µg/ml. Microscopic observations of evernic acid and optimization of its solubility were performed to further study this compound. This work confirmed the anti-biofilm potential of depsides, especially evernic acid, and allows to establish the structure–activity relationships to better explain the anti-biofilm potential of these compounds.

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Flow Cytometry Antifungal Susceptibility Testing of Pathogenic Yeasts other than Candida albicans and Comparison with the NCCLS Broth Microdilution Test

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.44.10.2752-2758.2000 ◽

2000 ◽

Vol 44 (10) ◽

pp. 2752-2758 ◽

Cited By ~ 44

Author(s):

Rama Ramani ◽

Vishnu Chaturvedi

Keyword(s):

Flow Cytometry ◽

Candida Albicans ◽

Amphotericin B ◽

Susceptibility Testing ◽

Antifungal Susceptibility ◽

Antifungal Susceptibility Testing ◽

Broth Microdilution ◽

Nitrogen Base ◽

Microdilution Method ◽

Broth Microdilution Method

ABSTRACT Candida species other than Candida albicansfrequently cause nosocomial infections in immunocompromised patients. Some of these pathogens have either variable susceptibility patterns or intrinsic resistance against common azoles. The availability of a rapid and reproducible susceptibility-testing method is likely to help in the selection of an appropriate regimen for therapy. A flow cytometry (FC) method was used in the present study for susceptibility testing ofCandida glabrata, Candida guilliermondii,Candida krusei, Candida lusitaniae,Candida parapsilosis, Candida tropicalis, andCryptococcus neoformans based on accumulation of the DNA binding dye propidium iodide (PI). The results were compared with MIC results obtained for amphotericin B and fluconazole using the NCCLS broth microdilution method (M27-A). For FC, the yeast inoculum was prepared spectrophotometrically, the drugs were diluted in either RPMI 1640 or yeast nitrogen base containing 1% dextrose, and yeast samples and drug dilutions were incubated with amphotericin B and fluconazole, respectively, for 4 to 6 h. Sodium deoxycholate and PI were added at the end of incubation, and fluorescence was measured with a FACScan flow cytometer (Becton Dickinson). The lowest drug concentration that showed a 50% increase in mean channel fluorescence compared to that of the growth control was designated the MIC. All tests were repeated once. The MICs obtained by FC for all yeast isolates except C. lusitaniae were in very good agreement (within 1 dilution) of the results of the NCCLS broth microdilution method. Paired ttest values were not statistically significant (P = 0.377 for amphotericin B; P = 0.383 for fluconazole). Exceptionally, C. lusitaniae isolates showed higher MICs (2 dilutions or more) than in the corresponding NCCLS broth microdilution method for amphotericin B. Overall, FC antifungal susceptibility testing provided rapid, reproducible results that were statistically comparable to those obtained with the NCCLS method.

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In vitro activity of a new echinocandin, LY303366, compared with those of amphotericin B and fluconazole against clinical yeast isolates.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.41.5.1156 ◽

1997 ◽

Vol 41 (5) ◽

pp. 1156-1157 ◽

Cited By ~ 54

Author(s):

O Uzun ◽

S Kocagöz ◽

Y Cetinkaya ◽

S Arikan ◽

S Unal

Keyword(s):

Candida Albicans ◽

Amphotericin B ◽

Vitro Activity ◽

In Vitro Activity ◽

Broth Microdilution ◽

Microdilution Method ◽

Broth Microdilution Method

The in vitro activity of LY303366, a new echinocandin derivative, was evaluated with 191 yeast isolates by a broth microdilution method. The MICs at which 50% of the isolates were inhibited were 0.125 microg/ml for Candida albicans and C. tropicalis, 0.25 microg/ml for C. krusei, C. kefyr, and C. glabrata, and 2.0 microg/ml for C. parapsilosis.

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Novel Fluorescent Broth Microdilution Method for Fluconazole Susceptibility Testing of Candida albicans

Journal of Clinical Microbiology ◽

10.1128/jcm.39.7.2708-2712.2001 ◽

2001 ◽

Vol 39 (7) ◽

pp. 2708-2712 ◽

Cited By ~ 10

Author(s):

R. S. Liao ◽

R. P. Rennie ◽

J. A. Talbot

Keyword(s):

Candida Albicans ◽

Susceptibility Testing ◽

Broth Microdilution ◽

Microdilution Method ◽

Broth Microdilution Method

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Lipidomics of Candida albicans biofilms reveals phase-dependent production of phospholipid molecular classes and role for lipid rafts in biofilm formation

Microbiology ◽

10.1099/mic.0.051086-0 ◽

2011 ◽

Vol 157 (11) ◽

pp. 3232-3242 ◽

Cited By ~ 63

Author(s):

Ali Abdul Lattif ◽

Pranab K. Mukherjee ◽

Jyotsna Chandra ◽

Mary R. Roth ◽

Ruth Welti ◽

...

Keyword(s):

Candida Albicans ◽

Biosynthetic Pathway ◽

Bloodstream Infections ◽

Unsaturation Index ◽

Lipid Profiles ◽

Planktonic Cells ◽

Gene Encoding ◽

Aureobasidin A ◽

Developmental Phases ◽

Candida Albicans Biofilms

Candida albicans-associated bloodstream infections are linked to the ability of this yeast to form biofilms. In this study, we used lipidomics to compare the lipid profiles of C. albicans biofilms and planktonic cells, in early and mature developmental phases. Our results showed that significant differences exist in lipid composition in both developmental phases. Biofilms contained higher levels of phospholipid and sphingolipids than planktonic cells (nmol per g biomass, P<0.05 for all comparisons). In the early phase, levels of lipid in most classes were significantly higher in biofilms compared to planktonic cells (P≤0.05). The ratio of phosphatidylcholine to phosphatidylethanolamine was lower in biofilms compared to planktonic cells in both early (1.17 vs 2.52, P≤0.001) and late (2.34 vs 3.81, P≤0.001) developmental phases. The unsaturation index of phospholipids decreased with time, with this effect being particularly strong for biofilms. Inhibition of the biosynthetic pathway for sphingolipid [mannosyl diinositolphosphoryl ceramide, M(IP)2C] by myriocin or aureobasidin A, and disruption of the gene encoding inositolphosphotransferase (Ipt1p), abrogated the ability of C. albicans to form biofilms. The differences in lipid profiles between biofilms and planktonic Candida cells may have important implications for the biology and antifungal resistance of biofilms.

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Exopolysaccharide matrix of developed candida albicans biofilms after exposure to antifungal agents

Brazilian Dental Journal ◽

10.1590/s0103-64402012000600016 ◽

2012 ◽

Vol 23 (6) ◽

pp. 716-722 ◽

Cited By ~ 10

Author(s):

Wander José da Silva ◽

Letícia Machado Gonçalves ◽

Jayampath Seneviratne ◽

Nipuna Parahitiyawa ◽

Lakshman Perera Samaranayake ◽

...

Keyword(s):

Candida Albicans ◽

Metabolic Activity ◽

Laser Scanning ◽

Antifungal Agents ◽

Live Cells ◽

Confocal Laser ◽

Xtt Assay ◽

Significance Level ◽

Biofilm Architecture ◽

Candida Albicans Biofilms

This study aimed to evaluate the effects of fluconazole or nystatin exposure on developed Candida albicans biofilms regarding their exopolysaccharide matrix. The minimal inhibitory concentration (MIC) against fluconazole or nystatin was determined for C. albicans reference strain (ATCC 90028). Poly(methlymethacrylate) resin (PMMA) specimens were fabricated according to the manufacturer's instructions and had their surface roughness measured. Biofilms were developed on specimens surfaces for 48 h and after that were exposed during 24 h to fluconazole or nystatin prepared in a medium at MIC, 10 x MIC or 100 x MIC. Metabolic activity was evaluated using an XTT assay. Production of soluble and insoluble exopolysaccharide and intracellular polysaccharides was evaluated by the phenol-sulfuric method. Confocal laser scanning microscope was used to evaluate biofilm architecture and percentage of dead/live cells. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. The presence of fluconazole or nystatin at concentrations higher than MIC results in a great reduction of metabolic activity (p<0.001). At MIC or 10 x MIC, fluconazole showed high amounts of intracellular polysaccharides (p<0.05), but did not affect the exopolysaccharide matrix (p>0.05). The exposure to nystatin also did not alter the exopolysaccharide matrix at all the tested concentrations (p>0.05). Biofilm architecture was not affected by either of the antifungal agents (p>0.05). Nystatin promoted higher proportion of dead cells (p<0.05). It may be concluded that fluconazole and nystatin above the MIC concentration reduced the metabolic activity of C. albicans biofilms; however, they were not able to alter the exopolysaccharide matrix and biofilm architecture.

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Analysis of Proteus mirabilis Distribution in Multi-Species Biofilms on Urinary Catheters and Determination of Bacteria Resistance to Antimicrobial Agents

Polish Journal of Microbiology ◽

10.33073/pjm-2013-052 ◽

2013 ◽

Vol 62 (4) ◽

pp. 377-384 ◽

Cited By ~ 7

Author(s):

Magdalena Moryl ◽

Agnieszka Torzewska ◽

Paweł Jałmużna ◽

Antoni Różalski

Keyword(s):

High Throughput Screening ◽

Bacterial Resistance ◽

Antimicrobial Agents ◽

Planktonic Cells ◽

Screening Assay ◽

Microdilution Method ◽

High Throughput Screening Assay ◽

Broth Microdilution Method ◽

Catheter Surface

The objectives of the investigation presented in this paper were: to examine the frequency of P. mirabilis isolation from catheters and assess the complexity of multi-species biofilms which these bacteria form, as well as to determine the vulnerability of planktonic and sessile P. mirabilis populations to popular antibiotics and compare it to the susceptibility of other Gram-negative bacteria isolated as associated flora from multi-species biofilm. 88 urological catheters, collected from long-term catheterized patients were examined. Uropathogens were recovered from the catheter surface by sonication, and identified on standard diagnostic media. The broth-microdilution method and the MBEC High-throughput Screening assay were used to determine the bacterial resistance to antibiotics. 279 microorganisms were isolated from 88 urinary catheter biofilms. The Enterobacteriaceae family were the most frequently detected bacteria (53.2% of isolates), whereas Proteus spp. isolation accounted for 17.9%, which placed these bacilli on the third position in the Enterobacteraceae family. Among all the tested drugs, amikacin and cephalosporins (ceftriaxone, cefotaxime and cefaclor) exhibited the highest activity against P. mirabilis planktonic cells, 86% and 73% of strains were susceptible to these antibiotics, respectively. 100% of P. mirabilis sessile forms were resistant to cefepime, ciprofloxacin, gatifloxacin, and norfloxacin. Amikacin and ceftriaxone affected only 5% of sessile forms. The planktonic cells of the other studied uropathogens were mostly vulnerable to the all tested drugs (exception P. aeruginosa strains), the most effective of which occurred to be amikacin and cefepime. Obtained MBECs values were 2-512-fold higher than MICs assessed for planktonic forms.

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Comparative resistance of Candida albicans clinical isolates to fluconazole and itraconazole in vitro and in vivo in a murine model.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.40.6.1342 ◽

1996 ◽

Vol 40 (6) ◽

pp. 1342-1345 ◽

Cited By ~ 18

Author(s):

A Valentin ◽

R Le Guennec ◽

E Rodriguez ◽

J Reynes ◽

M Mallie ◽

...

Keyword(s):

Candida Albicans ◽

Murine Model ◽

Survival Rates ◽

Drug Regimen ◽

Clinical Isolates ◽

In Vitro Susceptibility ◽

Microdilution Method ◽

Broth Microdilution Method

Relationships between azole susceptibility and in vivo response to antifungal therapy in a murine model of candidiasis were investigated for Candida albicans isolates sampled from human immunodeficiency virus type 1-positive patients with oropharyngeal candidiasis. The susceptibilities of seven clinical isolates and two reference strains to fluconazole (FCZ) and itraconazole (ITZ) were determined in vitro by the broth microdilution method. Four isolates were resistant to FCZ and ITZ, two were susceptible to both azoles, and three were resistant to FCZ and susceptible to ITZ (dissociated resistance). CD1 mice were inoculated with each isolate and treated with either FCZ or ITZ (drug regimen, 5 mg/kg of body weight twice daily for 5 days). Quantitative cultures of kidneys were performed at the end of the treatment. On the other hand, the survival rates of the mice were followed daily. These two parameters were clearly correlated with in vitro susceptibility. Thus, the phenomenon of a dissociation of resistance to FCZ and ITZ may be found in vivo as well as in vitro.

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The Structure-Activity Relationship of Pterostilbene Against Candida albicans Biofilms

Molecules ◽

10.3390/molecules22030360 ◽

2017 ◽

Vol 22 (3) ◽

pp. 360 ◽

Cited By ~ 7

Author(s):

Dan-Dan Hu ◽

Ri-Li Zhang ◽

Yong Zou ◽

Hua Zhong ◽

En-Sheng Zhang ◽

...

Keyword(s):

Candida Albicans ◽

Structure Activity Relationship ◽

Activity Relationship ◽

Structure Activity ◽

Relationship Of ◽

Candida Albicans Biofilms

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Comparative Evaluation of a New Fluorescent Carboxyfluorescein Diacetate-Modified Microdilution Method for Antifungal Susceptibility Testing of Candida albicans Isolates

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.46.10.3236-3242.2002 ◽

2002 ◽

Vol 46 (10) ◽

pp. 3236-3242 ◽

Cited By ~ 9

Author(s):

Robert S. Liao ◽

Robert P. Rennie ◽

James A. Talbot

Keyword(s):

Candida Albicans ◽

Susceptibility Testing ◽

Antifungal Susceptibility ◽

Antifungal Drugs ◽

Alamar Blue ◽

Broth Microdilution ◽

Modified Method ◽

Microdilution Method ◽

Growth Phenomenon ◽

Broth Microdilution Method

ABSTRACT This report presents a fluorescent carboxyfluorescein diacetate (CFDA)-modified microdilution method used for the susceptibility testing of Candida albicans to amphotericin B, fluconazole, ketoconazole, itraconazole, voriconazole, and flucytosine. Four different broth microdilution susceptibility testing methods were simultaneously evaluated at 24 and 48 h. The MICs determined using the CFDA-modified method (MICcfda) were compared to those obtained by the standard broth microdilution method (MICvisual) and a procedure employing the indicator Alamar blue (MICalamar). The reference MIC was determined visually as recommended by the NCCLS M27-A protocol, and then quantified spectrophotometrically following agitation (MICspec). The CFDA-modified microdilution method was demonstrated to effectively determine the MICs for all the antifungal drugs tested at both 24 and 48 h. The results from both the MICspec and MICcfda methods yielded >80% agreement within ±1 dilution and >90% agreement within ±2 dilutions at 24 h in comparison to the reference MICvisual method, respectively. The trailing growth phenomenon that occurs with azole antifungal drugs and many strains of C. albicans did not inhibit the effectiveness of the MICspec and MICcfda methods. The MICspec and MICcfda methods shared 92.8% agreement within ±1 dilution at 24 h and 87.6% agreement within ±1 dilution at 48 h.

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