In Vitro Pharmacodynamic Properties of Three Antifungal Agents against Preformed<i>Candida albicans</i>Biofilms Determined by Time-Kill Studies

Ramage, Gordon; VandeWalle, Kacy; Bachmann, Stefano P.; Wickes, Brian L.; López-Ribot, José L.

doi:10.1128/aac.46.11.3634-3636.2002

Cited by 228 publications

(165 citation statements)

References 15 publications

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“…The development and characterization of Candida biofilms on bioprosthetic surfaces that are components of indwelling devices are well documented (5,13,14,23). These studies have shown that Candida biofilm development is closely associated with the generation of an extracellular matrix and that mature biofilms show a highly heterogeneous structure and grow variably depending on the topography of the substrate.…”

Section: Discussionmentioning

confidence: 95%

“…It is now recognized that antibiotic resistance is a general trait associated with biofilm organisms, including bacteria (21,22) and fungi (15,23). Several theories have been proposed to explain this phenomenon, including the growth rate differen- tials (9, 10), a recalcitrant phenotypic state (4), the production of antibiotic-degrading enzymes (11), and the extracellular polymeric material that may act as an adsorbent or a reactant with the antimicrobial (30).…”

Section: Discussionmentioning

confidence: 99%

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In Vitro Method To Study Antifungal Perfusion in Candida Biofilms

Samaranayake

Yau

et al. 2005

J Clin Microbiol

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Antimycotic perfusion through Candida biofilms was demonstrated by a modification of a simple in vitro diffusion cell bioassay system. Using this model, the perfusion of three commonly used antifungal agents, amphotericin B, fluconazole, and flucytosine, was investigated in biofilms of three different Candida species (i.e., Candida albicans, Candida parapsilosis, and Candida krusei) that were developed on microporous filters. Scanning electron microscopy revealed that C. albicans formed a contiguous biofilm with tightly packed blastospores and occasional hyphae compared with C. parapsilosis and C. krusei, which developed confluent biofilms displaying structural heterogeneity and a lesser cell density, after 48 h of incubation on nutrient agar. Minor structural changes were also perceptible on the superficial layers of the biofilm after antifungal perfusion. The transport of antifungals to the distal biofilm-substratum interface was most impeded by C. albicans biofilms in comparison to C. parapsilosis and C. krusei. Fluconazole and flucytosine demonstrated similar levels of perfusion, while amphotericin B was the least penetrant through all three biofilms, although the latter appeared to cause the most structural damage to the superficial cells of the biofilm compared with the other antifungals. These results suggest that the antifungal perfusion through biofilm mode of growth in Candida is dependent both on the antimycotic and the Candida species in question, and in clinical terms, these phenomena could contribute to the failure of Candida biofilm-associated infections. Finally, the in vitro model we have described should serve as a useful system to investigate the complex interactions that appear to operate in vivo within the biofilm-antifungal interphase.

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Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

In Vitro Method To Study Antifungal Perfusion in Candida Biofilms

Samaranayake

Yau

et al. 2005

J Clin Microbiol

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“…Overall this microtiter platebased model of biofilm formation offers a simple, flexible, relatively inexpensive, accurate and reproducible alternative for biofilm formation that is compatible with the widely available 96 well microplate platform. It can be used to examine multiple parameters and factors influencing biofilm formation, to estimate the biofilm-forming ability of multiple fungal isolates and mutant strains, and more importantly for the purpose of these studies, it can be easily adapted for antifungal susceptibility testing of fungal biofilms following the procedures described below 25,31,32 .…”

Section: Introductionmentioning

confidence: 99%

A simple and reproducible 96-well plate-based method for the formation of fungal biofilms and its application to antifungal susceptibility testing

et al. 2008

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The incidence of fungal infections has increased significantly over the past decades. Very often these infections are associated with biofilm formation on implanted biomaterials and/or host surfaces. This has important clinical implications since fungal biofilms display properties that are dramatically different from planktonic (free-living) populations, including increased resistance to antifungal agents. Here we describe a rapid and highly reproducible 96 well microtiter-based method for the formation of fungal biofilms which is easily adaptable for antifungal susceptibility testing. This model is based on the ability of metabolically active sessile cells to reduce a tetrazolium salt (XTT) to water-soluble orange formazan compounds, the intensity of which can then be determined using a microtiter-plate reader. The entire procedure takes approximately two days to complete. This technique simplifies biofilm formation and quantification, making it more reliable and comparable among different laboratories, a necessary step towards the standardization of antifungal susceptibility testing of biofilms.

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“…93 Researchers have observed that 20 times the MIC of commonly used antifungals was required to achieve a significant reduction in cell numbers. 94 Thus, higher levels of AmB-D are required to manage biofilm-related infection in the clinic, and this is not advisable because of the toxic behavior of AmB.…”

Section: Regression Of C Albicans Biofilm Induced By Amb-pgamentioning

confidence: 99%

Self-assembled amphotericin B-loaded polyglutamic acid nanoparticles: preparation, characterization and in vitro potential against Candida albicans

Zia¹,

Khan²,

Zubair³

et al. 2015

IJN

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In the present study, we developed a self-assembled biodegradable polyglutamic acid (PGA)-based formulation of amphotericin B (AmB) and evaluated its in vitro antifungal potential against Candida albicans . The AmB-loaded PGA nanoparticles were prepared in-house and had a mean size dimension of around 98±2 nm with a zeta potential of −35.2±7.3 mV. Spectroscopic studies revealed that the drug predominantly acquires an aggregated form inside the formulation with an aggregation ratio above 2. The PGA-based AmB formulation was shown to be highly stable in phosphate-buffered saline as well as in serum (only 10%–20% of the drug was released after 10 days). The AmB–PGA nanoparticles were less toxic to red blood cells (<15% lysis at an AmB concentration of 100 μg/mL after 24 hours) when compared with Fungizone ® , a commercial antifungal product. An MTT assay showed that the viability of mammalian cells (KB and RAW 264.7) was negligibly affected at AmB concentrations as high as 200 μg/mL. Histopathological examination of mouse kidney revealed no signs of tissue necrosis. The AmB–PGA formulation showed potent antimicrobial activity similar to that of Fungizone against C. albicans . Interestingly, AmB-bearing PGA nanoparticles were found to inhibit biofilm formation to a considerable extent. In summary, AmB–PGA nanoparticles showed highly attenuated toxicity when compared with Fungizone, while retaining equivalent active antifungal properties. This study indicates that the AmB–PGA preparation could be a promising treatment for various fungal infections.

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In Vitro Pharmacodynamic Properties of Three Antifungal Agents against PreformedCandida albicansBiofilms Determined by Time-Kill Studies

Cited by 228 publications

References 15 publications

In Vitro Method To Study Antifungal Perfusion in Candida Biofilms

In Vitro Method To Study Antifungal Perfusion in Candida Biofilms

A simple and reproducible 96-well plate-based method for the formation of fungal biofilms and its application to antifungal susceptibility testing

Self-assembled amphotericin B-loaded polyglutamic acid nanoparticles: preparation, characterization and in vitro potential against Candida albicans

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