Lipid core nanoparticles as a broad strategy to reverse fluconazole resistance in multiple Candida species

Lipid-core nanocapsules containing simvastatin do not affect the biochemical and hematological indicators of toxicity in rats

Our research group previously studied the effectiveness of lipid-core nanocapsules (LNC) containing simvastatin (SV-LNC) in treating cognitive impairment in rats. While our results were promising, we needed to evaluate the potential toxicity of the nanoparticles themselves. This study aimed to compare the biochemical and hematological parameters of adult Wistar rats receiving LNC or SV-LNC to those receiving low doses of simvastatin crystals dispersed in a saline solution over 45 days. We discovered that LNC and SV-LNC, which are both nanometers in size with low polydispersity index, negative zeta potential, and high SV encapsulation efficacy, were not more toxic than SV crystals based on various biochemical markers of hepatic, pancreatic, renal, mineral, bony, alkaline phosphatase, glucose, and uric acid damage. Furthermore, LNC exhibited no toxicity for hematological parameters, including red and white blood cell counts. Based on this animal model of toxicological study, our findings suggest that long-term administration of LNC is a safe and promising nanocarrier.

Improving antifungal lipid-based drug delivery against Candida: a review

INTRODUCTION

Fungal infections, particularly those caused by Candida spp. have increased in recent years. A primary contributor to this surge was the COVID-19 pandemic, where many hospitalized patients had secondary fungal infections. Additionally, the emergence of resistant and multi-resistant fungal strains has become increasingly problematic due to the limited therapeutic options available in antifungal treatments.

AREAS COVERED

This review presents a comprehensive analysis of recent studies focused on the development and characterization of lipid-based nanosystems as an emerging and promising therapeutic alternative. These systems have been evaluated for their potential to deliver antifungal agents specifically targeting resistant Candida spp. strains, offering a controlled and sustained release of drugs.

EXPERT OPINION

Lipid-based nanomaterials are promising tools for the controlled and sustained release of drugs, particularly in treating Candida spp. infections. Although substantial research has been dedicated to development of these nanomaterials, only a few have reached clinical application, such as liposomal amphotericin B, for example. Therefore, it is critical to push forward with advancements to bring these nanomedicines into clinical practice, where they can contribute meaningfully to mitigating the challenge of resistant and lethal fungal strains.

Pluronic F-127 Enhances the Antifungal Activity of Fluconazole against Resistant Candida Strains

Candida strains as the most frequent causes of infections, along with their increased drug resistance, pose significant clinical and financial challenges to the healthcare system. Some polymeric excipients were reported to interfere with the multidrug resistance mechanism. Bearing in mind that there are a limited number of marketed products with fluconazole (FLU) for the topical route of administration, Pluronic F-127 (PLX)/FLU formulations were investigated in this work. The aims of this study were to investigate (i) whether PLX-based formulations can increase the susceptibility of resistant Candida strains to FLU, (ii) whether there is a correlation between block polymer concentration and the antifungal efficacy of the FLU-loaded PLX formulations, and (iii) what the potential mode of action of PLX assisting FLU is. The yeast growth inhibition upon incubation with PLX formulations loaded with FLU was statistically significant. The highest efficacy of the azole agent was observed in the presence of 5.0 and 10.0% w/v of PLX. The upregulation of the CDR1/CDR2 genes was detected in the investigated Candida strains, indicating that the efflux of the drug from the fungal cell was the main mechanism of the resistance.

Nanotherapeutics for the delivery of antifungal drugs

The treatment of fungal infections is challenging with high death rates reported among immunocompromised patients. The currently available antifungals suffer from poor bioavailability and solubility, pharmacokinetics, and drug resistance, with limited cellular uptake. The clinical pipeline of new antifungals is dry. The incorporation of antifungal drugs into polymer-based nanocarriers to form nanotherapeutics is a promising approach to enhance the therapeutic outcomes of the available antifungal drugs. This review summarizes different polymer-based nanotherapeutics strategies that have been explored for the delivery of antifungals, resulting in enhanced therapeutic outcomes, such as improved pharmacokinetics, targeted/sustained delivery, prolonged drug circulation, retention of the drugs at the localized site of action, and overcoming drug resistance when compared with the free antifungal drugs.

A pH-tuned chitosan-PLGA nanocarrier for fluconazole delivery reduces toxicity and improves efficacy against resistant Candida

Fluconazole (FLZ) is a broad-spectrum antifungal used against Candida infections. Candida auris displays resistance to FLZ. Drug nanocarriers composed of natural (chitosan, C) or synthetic polymers (polylactide co-glycolide, PLGA) show improved drug characteristics, efficacy and reduction in toxicity. Here, C-PLGA nanoparticles (110 nm) were synthesized by coacervation method and loaded with FLZ, achieving ~8-wt% drug loading. The nanoformulation displayed pH-tuned slow sustained drug release (83 %) up to 5 d, at pH 4, while 34 % release occurred at pH 7.0. Fluorescent-tagged C-PLGA-NPs were localized on the Candida cell wall/membrane as seen by confocal microscopy. This resulted in ~1.9-fold reduced efflux of R6G dye as compared to bare drug treatment in Candida albicans and resistant C. auris. The nanoformulation showed a significant 16- and 64-fold (p < 0.0001) enhanced antifungal activity (MIC 5 and 2.5 μg/ml) against C. albicans and C. auris, respectively, as compared to FLZ. The nanoformulation showed highly effective antifungal activity in-vivo against C. albicans and C. auris. Moreover, the nephrotoxicity and hepatotoxicity was negligible. Thus, PLGA NPs-mediated fluconazole delivery can contribute to increased drug efficacy and to reduce the problem of fungal resistance.

Advances in the Application of the Non-Conventional Yeast Pichia kudriavzevii in Food and Biotechnology Industries

Pichia kudriavzevii is an emerging non-conventional yeast which has attracted increased attention for its application in food and biotechnology areas. It is widespread in various habitats and often occurs in the spontaneous fermentation process of traditional fermented foods and beverages. The contributions of P. kudriavzevii in degrading organic acid, releasing various hydrolase and flavor compounds, and displaying probiotic properties make it a promising starter culture in the food and feed industry. Moreover, its inherent characteristics, including high tolerance to extreme pH, high temperature, hyperosmotic stress and fermentation inhibitors, allow it the potential to address technical challenges in industrial applications. With the development of advanced genetic engineering tools and system biology techniques, P. kudriavzevii is becoming one of the most promising non-conventional yeasts. This paper systematically reviews the recent progress in the application of P. kudriavzevii to food fermentation, the feed industry, chemical biosynthesis, biocontrol and environmental engineering. In addition, safety issues and current challenges to its use are discussed.

Progress of polymer-based strategies in fungal disease management: Designed for different roles

Fungal diseases have posed a great challenge to global health, but have fewer solutions compared to bacterial and viral infections. Development and application of new treatment modalities for fungi are limited by their inherent essential properties as eukaryotes. The microorganism identification and drug sensitivity analyze are limited by their proliferation rates. Moreover, there are currently no vaccines for prevention. Polymer science and related interdisciplinary technologies have revolutionized the field of fungal disease management. To date, numerous advanced polymer-based systems have been developed for management of fungal diseases, including prevention, diagnosis, treatment and monitoring. In this review, we provide an overview of current needs and advances in polymer-based strategies against fungal diseases. We high light various treatment modalities. Delivery systems of antifungal drugs, systems based on polymers' innate antifungal activities, and photodynamic therapies each follow their own mechanisms and unique design clues. We also discuss various prevention strategies including immunization and antifungal medical devices, and further describe point-of-care testing platforms as futuristic diagnostic and monitoring tools. The broad application of polymer-based strategies for both public and personal health management is prospected and integrated systems have become a promising direction. However, there is a gap between experimental studies and clinical translation. In future, well-designed in vivo trials should be conducted to reveal the underlying mechanisms and explore the efficacy as well as biosafety of polymer-based products.

Enhancing the Antifungal Activity and Ophthalmic Transport of Fluconazole from PEGylated Polycaprolactone Loaded Nanoparticles

Fungal eye infections are caused mainly by an eye injury and can result in serious eye damage. Fluconazole (FLZ), a broad-spectrum antifungal agent, is a poorly soluble drug with a risk of hepatotoxicity. This work aimed to investigate the antifungal activity, ocular irritation, and transport of FLZ-loaded poly (ε-caprolactone) nanoparticles using a rabbit eye model. Three formulation factors affecting the nanoparticle's size, zeta potential, and entrapment efficiency were optimized utilizing the Box-Behnken design. Morphological characteristics and antifungal activity of the optimized nanoparticles were studied. The optimized nanoparticles were loaded into thermosensitive in situ hydrogel and hydroxypropylmethylcellulose (HPMC) hydrogel ophthalmic formulations. The rheological behavior, in vitro release and in vivo corneal transport were investigated. Results revealed that the percentage of poly (ε-caprolactone) in the nanoparticle matrix, polymer addition rate, and mixing speed significantly affected the particle size, zeta potential, and entrapment efficiency. The optimized nanoparticles were spherical in shape and show an average size of 145 nm, a zeta potential of -28.23 mV, and a FLZ entrapment efficiency of 98.2%. The antifungal activity of FLZ-loaded nanoparticles was significantly higher than the pure drug. The developed ophthalmic formulations exhibited a pseudoplastic flow, prolonged the drug release and were found to be non-irritating to the cornea. The prepared FLZ pegylated nanoparticles were able to reach the posterior eye segment without eye irritation. As a result, the developed thermosensitive in situ hydrogel formulation loaded with FLZ polymeric nanoparticles is a promising drug delivery strategy for treating deep fungal eye infections.

Role of nanostructured lipid carriers in the expression alterations of ATP-binding cassette transporter genes in fluconazole-resistant Candida glabrata

Introduction: This study was proposed to assess the potential role of efflux transporters in reversing fluconazole resistance in Candida glabrata isolates treated with fluconazole loaded nanostructured lipid carriers (FLZ-NLCs). Methods: The ultrasound technique was used to synthesize the FLZ-NLCs. Four fluconazole-resistant, as well as one susceptible standard C. glabrata isolates, were applied and exposed to FLZ/ FLZ-NLCs for 20 h at 37°C. Real-time PCRs were done to estimate the likely changes in ATP-binding cassette transporter genes. Results: Similar to the FLZ-exposed-susceptible standard strain which showed no alteration, the genes were not up-regulated significantly under the FLZ-NLCs treated condition. While they were over-expressed when the yeasts were treated with fluconazole. Conclusion: It is highly suggested that due to the nature of the NLCs which shields the whole conformation of the drug, FLZ is not recognized by the efflux transporter subunits and consequently the translocation would not happen.

Validation of an innovative analytical method for simultaneous quantification of curcumin and fluconazole using high-performance liquid chromatography from nanostructured lipid carriers

Vulvovaginal candidiasis is a public health problem with a high incidence among female patients. Currently, there is an increase in the identification of Candida spp. resistant to current therapy, making it necessary to search for new therapeutic alternatives. The synergistic potential of curcumin with fluconazole is described in the literature. However, due to its high lipophilicity, it is necessary to use drug-delivery systems to adequately explore its potential, among which is the nanostructured lipid carrier. However, to date, there is no validated method of high-performance liquid chromatography for simultaneous determination of fluconazole and curcumin in the literature. Thus, the present work developed a high-performance liquid chromatography method for simultaneous determination of fluconazole and curcumin co-encapsulated in nanostructured lipid carrier which was validated according to the International Conference on Harmonization (Technical Requirements for Registration of Pharmaceuticals for Human Use) - Q2 (R1) and the Food and Drug Administration - Guidance for Bioanalytical Method. The method was applied to determine the encapsulation efficiency and drug-loading of curcumin and fluconazole in nanostructured lipid carriers. The developed method proved to be selective, precise, accurate, and robust for the simultaneous determination of both drugs, enabling the quantification of encapsulation efficiency and drug-loading of curcumin and fluconazole in nanostructured lipid carriers.

Striking Back against Fungal Infections: The Utilization of Nanosystems for Antifungal Strategies

Fungal infections have become a major health concern, given that invasive infections by Candida, Cryptococcus, and Aspergillus species have led to millions of mortalities. Conventional antifungal drugs including polyenes, echinocandins, azoles, allylamins, and antimetabolites have been used for decades, but their limitations include off-target toxicity, drug-resistance, poor water solubility, low bioavailability, and weak tissue penetration, which cannot be ignored. These drawbacks have led to the emergence of novel antifungal therapies. In this review, we discuss the nanosystems that are currently utilized for drug delivery and the application of antifungal therapies.

Silver nanoparticles, a promising treatment against clinically important fluconazole-resistant Candida glabrata

Resistance to azole antifungal agents is a challenging limitation in Candida glabrata treatment. It is associated with decreased intracellular concentrations of antifungal agents as a result of overexpression of efflux pumps on the cellular plasma membranes. This work evaluates the potential of silver nanoparticles (AgNPs) to reverse the resistance of fungal cells to fluconazole. Silver nanoparticles were prepared using wet chemical method and characterised by UV-Vis spectrophotometry, dynamic light scattering, and zeta potential. Broth microdilution and pour plates methods were used to study the anticandidal activity using two C. glabrata fluconazole-resistant strains (DSY565 and CBS138) known to overexpress active efflux pumps, and a standard fluconazole sensitive strain ATCC 22553. Silver nanoparticles-fluconazole combinations decreased concentrations of fluconazole substantially without compromising the activity. These findings suggest that AgNPs enhance the efficacy of fluconazole and offer a promising application in therapy of C. glabrata infections.

New nanotechnological formulation based on amiodarone-loaded lipid core nanocapsules displays anticryptococcal effect

Cryptococcus neoformans is the etiological agent of cryptococcal meningoencephalitis. The recommended available treatment has low efficiency, with high toxicity and resistance as recurrent problems. In the search of new treatment protocols, the proposal of new pharmacological approaches is considered an innovative strategy, mainly nanotechnological systems considering fungal diseases. The antiarrhythmic drug amiodarone has demonstrated antifungal activity against a range of fungi, including C. neoformans. Here, considering the importance of calcium storage mediated by transporters on cryptococcal virulence, we evaluated the use of the calcium channel blocker amiodarone as an alternative therapy for cryptococcosis. C. neoformans displayed high sensitivity to amiodarone, which was also synergistic with fluconazole. Amiodarone treatment influenced some virulence factors, interrupting the calcium-calcineurin signaling pathway. Experiments with murine cryptococcosis models revealed that amiodarone treatment increased the fungal burden in the lungs, while its combination with fluconazole did not improve treatment compared to fluconazole alone. In addition, we have developed different innovative nanotechnological formulations, one of which combining two drugs with different mechanisms of action. Lipid-core nanocapsules (LNC) loaded with amiodarone (LNC_AMD), fluconazole (LNC_FLU) and both (LNC_AMD+FLU) were produced to achieve a better efficacy in vivo. In an intranasal model of treatment, all the LNC formulations had an antifungal effect. In an intraperitoneal treatment, LNC_AMD showed an enhanced anticryptococcal effect compared to the free drug, whereas LNC_FLU or LNC_AMD+FLU displayed no differences from the free drugs. In this way, nanotechnology using amiodarone formulations could be an effective therapy for cryptococcal infections.

HPLC Method Validated for Quantification of Fluconazole Co-Encapsulated with Propolis Within Chitosan Nanoparticles

Considering the cases of fungal resistance to classic antifungals, it is necessary to develop more efficient and innovative therapies capable of reversing this situation. Fluconazole is an antifungal frequently used in the treatment of mycosis and some fungi developed resistance to its mechanism of action. In this work, fluconazole and green propolis were co-encapsulated in chitosan nanoparticles to be explored in order to promote a synergistic effect to enhance its therapeutic efficacy. However, because of the complexity of the chemical composition of green propolis, it was necessary to develop a simple and precise methodology to quantify fluconazole in the formulation. High Efficiency Liquid Chromatography methodology was developed and validated following the Brazilian regulatory guidelines (ANVISA, RDC 166/2017) for the separation of co-eluted peaks of fluconazole and green propolis in the nanoparticle supernatant. Applying the method developed, it was possible to quantify fluconazole in the same sample containing propolis. Thus, the results allow to affirm that it is a specific test, effective, precise and robust, which helped to determine the efficiency of association of the compounds within the nanoparticle. The method can be applied to quantify compounds that have similar chromatographic retention times.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-021-00954-2.

Nanoparticles as a Tool for Broadening Antifungal Activities

Fungal infections are diseases that are considered neglected although their infection rates have increased worldwide in the last decades. Thus, since the antifungal arsenal is restricted and many strains have shown resistance, new therapeutic alternatives are necessary. Nanoparticles are considered important alternatives to promote drug delivery. In this sense, the objective of the present study was to evaluate the contributions of newly developed nanoparticles to the treatment of fungal infections. Studies have shown that nanoparticles generally improve the biopharmaceutical and pharmacokinetic characteristics of antifungals, which is reflected in a greater pharmacodynamic potential and lower toxicity, as well as the possibility of prolonged action. It also offers the proposition of new routes of administration. Nanotechnology is known to contribute to a new drug delivery system, not only for the control of infectious diseases but for various other diseases as well. In recent years, several studies have emphasized its application in infectious diseases, presenting better alternatives for the treatment of fungal infections.

Lipo-PEG nano-ocular formulation successfully encapsulates hydrophilic fluconazole and traverses corneal and non-corneal path to reach posterior eye segment

The present study describes a special lipid-polyethylene glycol matrix solid lipid nanoparticles (SLNs; 138 nm; -2.07 mV) for ocular delivery. Success of this matrix to encapsulate (entrapment efficiency - 62.09%) a hydrophilic drug, fluconazole (FCZ-SLNs), with no burst release (67% release in 24 h) usually observed with most water-soluble drugs, is described presently. The system showed 164.64% higher flux than the marketed drops (Zocon^®) through porcine cornea. Encapsulation within SLNs and slow release did not compromise efficacy of FCZ-SLNs. Latter showed in vitro and in vivo antifungal effects, including antibiofilm effects comparable to free FCZ solution. Developed system was safe and stable (even to sterilisation by autoclaving); and showed optimal viscosity, refractive index and osmotic pressure. These SLNs could reach up to retina following application as drops. The mechanism of transport via corneal and non-corneal transcellular pathways is described by fluorescent and TEM images of mice eye cross sections. Particles streamed through the vitreous, crossed inner limiting membrane and reached the outer retinal layers.

Omeprazole nanoparticles suspension: Development of a stable liquid formulation with a view to pediatric administration

Omeprazole (OME) is often used to treat disorders associated with gastric hypersecretion in children but a liquid pediatric formulation of this medicine is not currently available. The aim of this study is to develop OME loaded nanoparticles with a view to the obtention of a liquid pharmaceutical dosage form. Eudragit® RS100 was selected as the skeleton material in the inner core and pH-sensitive Eudragit® L100-55 was used as the outer coating of the nanoparticles prepared by the nanoprecipitation method. Pharmacological activity was evaluated by induction of ethanol ulcers in mice. The OME nanoparticles exhibited mean diameters of 174 nm (±17), polydispersity index of 0.229 (±0.01), zeta potential values of -13 mV (±2.60) and encapsulation efficiency of 68.1%. The in vivo pharmacological assessment showed the ability of nanoparticles to protect mice stomach against ulcer formation. The prepared suspension of OME nanoparticles represents effective therapeutic strategy in a liquid pharmaceutical form with the possibility of pediatric administration.

The use of nanoparticles as alternative therapeutic agents against Candida infections: an up-to-date overview and future perspectives

Candida spp. are opportunistic fungi that can cause severe infections especially in immunocompromised patients. Candidiasis is currently the most frequent fungal disease affecting humans globally. This rise is attributed to the vast increase in resistance to antifungal agents. In recent years, the epidemiological and clinical relevance of fungal infections caused by Candida species have attracted a lot of interest with increasing reports of intrinsic and acquired resistance among Candida species. Thus, the formulation of novel, and efficient therapy for Candida infection persists as a critical challenge in modern medicine. The use of nanoparticle as a potential biomaterial to achieve this feat has gained global attention. Nanoparticles have shown promising antifungal activity, and thus, could be seen as the next generation antifungal agents. This review concisely discussed Candida infection with emphasis on anti-candida resistance mechanisms and the use of nanoparticles as potential therapeutic agents against Candida species. Moreover, the mechanisms of activity of nanoparticles against Candida species, recent findings on the anti-candida potentials of nanoparticles and future perspectives are also presented.

Phytol-Loaded Solid Lipid Nanoparticles as a Novel Anticandidal Nanobiotechnological Approach

Phytol is a diterpene alcohol and can be found as a product of the metabolism of chlorophyll in plants. This compound has been explored as a potential antimicrobial agent, but it is insoluble in water. In this study, we describe a novel approach for an interesting anticandidal drug delivery system containing phytol. Different formulations of phytol-loaded solid lipid nanoparticles (SLN) were designed and tested using a natural lipid, 1,3-distearyl-2-oleyl-glycerol (TG1). Different compositions were considered to obtain three formulations with 1:10, 1:5, and 1:3 w/w phytol/TG1 ratios. All the formulations were prepared by emulsification solvent evaporation method and had their physicochemical properties assessed. The biocompatibility assay was performed in the HEK-293 cell line and the antifungal efficacy was demonstrated in different strains of Candida ssp., including different clinical isolates. Spherical and uniform SLN (<300 nm, PdI < 0.2) with phytol-loading efficiency >65% were achieved. Phytol-loaded SLN showed a dose-dependent cytotoxic effect in the HEK-293 cell line. The three tested formulations of phytol-loaded SLN considerably enhanced the minimal inhibitory concentration of phytol against 15 strains of Candida spp. Considering the clinical isolates, the formulations containing the highest phytol/TG1 ratios showed MICs at 100%. Thus, the feasibility and potential of phytol-loaded SLN was demonstrated in vitro, being a promising nanocarrier for phytol delivery from an anticandidal approach.

Therapies and Vaccines Based on Nanoparticles for the Treatment of Systemic Fungal Infections

Treatment modalities for systemic mycoses are still limited. Currently, the main antifungal therapeutics include polyenes, azoles, and echinocandins. However, even in the setting of appropriate administration of antifungals, mortality rates remain unacceptably high. Moreover, antifungal therapy is expensive, treatment periods can range from weeks to years, and toxicity is also a serious concern. In recent years, the increased number of immunocompromised individuals has contributed to the high global incidence of systemic fungal infections. Given the high morbidity and mortality rates, the complexity of treatment strategies, drug toxicity, and the worldwide burden of disease, there is a need for new and efficient therapeutic means to combat invasive mycoses. One promising avenue that is actively being pursued is nanotechnology, to develop new antifungal therapies and efficient vaccines, since it allows for a targeted delivery of drugs and antigens, which can reduce toxicity and treatment costs. The goal of this review is to discuss studies using nanoparticles to develop new therapeutic options, including vaccination methods, to combat systemic mycoses caused by Candida sp., Cryptococcus sp., Paracoccidioides sp., Histoplasma sp., Coccidioides sp., and Aspergillus sp., in addition to providing important information on the use of different types of nanoparticles, nanocarriers and their corresponding mechanisms of action.

Nanosystems against candidiasis: a review of studies performed over the last two decades

The crescent number of cases of candidiasis and the increase in the number of infections developed by non-albicans species and by multi-resistant strains has taken the attention of the scientific community, which has been searching for new therapeutic alternatives. Among the alternatives found the use of nanosystems for delivery of drugs already commercialized and new biomolecules have grown, in order to increase stability, solubility, optimize efficiency and reduce adverse effects. In view of the growing number of studies involving technological alternatives for the treatment of candidiasis, the present review came with the intention of gathering studies from the last two decades that used nanotechnology for the treatment of candidiasis, as well as analysing them critically and pointing out the future perspectives for their application with this purpose. Different studies were considered for the development of this review, addressing nanosystems such as metallic nanoparticles, mesoporous silica nanoparticles, polymeric nanoparticles, liposomes, nanoemulsion, microemulsion, solid lipid nanoparticle, nanostructured lipid carrier, lipidic nanocapsules and liquid crystals; and different clinical presentations of candidiasis. As a general overview, nanotechnology has proven to be an important ally for the treatment against the diversity of candidiasis found in the clinic, whether in increasing the effectiveness of commercialized drugs and reducing their adverse effects, as well as allowing exploring more effectively properties therapeutics of new biomolecules.

Current Aspects in the Biology, Pathogeny, and Treatment of Candida krusei, a Neglected Fungal Pathogen

Fungal infections represent a constant and growing menace to human health, because of the emergence of new species as causative agents of diseases and the increment of antifungal drug resistance. Candidiasis is one of the most common fungal infections in humans and is associated with a high mortality rate when the fungi infect deep-seated organs. Candida krusei belongs to the group of candidiasis etiological agents, and although it is not isolated as frequently as other Candida species, the infections caused by this organism are of special relevance in the clinical setting because of its intrinsic resistance to fluconazole. Here, we offer a thorough revision of the current literature dealing with this organism and the caused disease, focusing on its biological aspects, the host-fungus interaction, the diagnosis, and the infection treatment. Of particular relevance, we provide the most recent genomic information, including the gene prediction of some putative virulence factors, like proteases, adhesins, regulators of biofilm formation and dimorphism. Moreover, C. krusei veterinary aspects and the exploration of natural products with anti-C. krusei activity are also included.

An update on the application of nano-scaled carriers against fluconazole-resistant Candida species: nanostructured lipid carriers or solid lipid nanoparticles?

Background and Purpose:

Encapsulation can lead to improved efficacy and safety of antifungal compounds. The attention of scientists has recently turned to biocompatible lipids as the carriers for the delivery of antifungal drugs, such as fluconazole. Although several research reports have already been published on fluconazole loaded solid lipid nanoparticles (FLZ-SLNs) and fluconazole loaded nanostructured lipid carriers (FLZ-NLCs), the possible advantages of NLCs over SLNs have not yet been fully established. Studies performed so far have given several contradictory results.

Materials and Methods:

Both formulations of fluconazole were synthesized using probe ultrasonication method and the characteristics were analyzed. Antifungal susceptibility testing (AFST) was performed with FLZ, FLZ-SLNs, and FLZ-NLCs using CLSI document M60 against some common fluconazole-resistant Candida species.

Results:

A significant decrease was observed in minimum inhibitory concentration values when both formulations were applied. Nonetheless, FLZ-NLCs were significantly more effective (P<0.05). However, three species groups were not statistically different in terms of the activity of FLZ-NLCs.

Conclusion:

Based on the obtained results, FLZ-NLCs could reverse the azole-resistance phenomenon in the most common Candida species more effectively, as compared to FLZ-SLNs.