Antifungal drug resistance of pathogenic fungi

Robust, pleiotropic drug resistance 5 (Pdr5)-mediated multidrug resistance is vigorously maintained in Saccharomyces cerevisiae cells during glucose and nitrogen limitation

Saccharomyces cerevisiae has sophisticated nutrient-sensing programs for responding to harsh environments containing limited nutrients. As a result, yeast cells can live in diverse environments, including animals, as a commensal or a pathogen. Because they live in mixed populations with other organisms that excrete toxic chemicals, it is of interest to know whether yeast cells maintain functional multidrug resistance mechanisms during nutrient stress. We measured the activity of Pdr5, the major Saccharomyces drug efflux pump under conditions of limiting nutrients. We demonstrate that the steady-state level of this transporter remains unchanged during growth in low concentrations of glucose and nitrogen even though two-dimensional gel electrophoresis revealed a decrease in the level of many proteins. We also evaluated rhodame 6G transport and resistance to three xenobiotic agents in rich (synthetic dextrose) and starvation medium. We demonstrate that Pdr5 function is vigorously maintained under both sets of conditions.

The Yin and Yang of Current Antifungal Therapeutic Strategies: How Can We Harness Our Natural Defenses?

Fungal infections have aroused much interest over the last years because of their involvement in several human diseases. Immunocompromission due to transplant-related therapies and malignant cancer treatments are risk factors for invasive fungal infections, but also aggressive surgery, broad-spectrum antibiotics and prosthetic devices are frequently associated with infectious diseases. Current therapy is based on the administration of antifungal drugs, but the occurrence of resistant strains to the most common molecules has become a serious health-care problem. New antifungal agents are urgently needed and it is essential to identify fungal molecular targets that could offer alternatives for development of treatments. The fungal cell wall and plasma membrane are the most important structures that offer putative new targets which can be modulated in order to fight microbial infections. The development of monoclonal antibodies against new targets is a valid therapeutic strategy, both to solve resistance problems and to support the immune response, especially in immunocompromised hosts. In this review, we summarize currently used antifungal agents and propose novel therapeutic approaches, including new fungal molecular targets to be considered for drug development.

Fluorescent Tracking of the Endoplasmic Reticulum in Live Pathogenic Fungal Cells

In fungal cells, the endoplasmic reticulum (ER) harbors several of the enzymes involved in the biosynthesis of ergosterol, an essential membrane component, making this organelle the site of action of antifungal azole drugs, used as a first-line treatment for fungal infections. This highlights the need for specific fluorescent labeling of this organelle in cells of pathogenic fungi. Here we report on the development and evaluation of a collection of fluorescent ER trackers in a panel of Candida, considered the most frequently encountered pathogen in fungal infections. These trackers enabled imaging of the ER in live fungal cells. Organelle specificity was associated with the expression of the target enzyme of antifungal azoles that resides in the ER; specific ER labeling was not observed in mutant cells lacking this enzyme. Labeling of live Candida cells with a combination of a mitotracker and one of the novel fungal ER trackers revealed sites of contact between the ER and mitochondria. These fungal ER trackers therefore offer unique molecular tools for the study of the ER and its interactions with other organelles in live cells of pathogenic fungi.

Primary antifungal prophylaxis for cryptococcal disease in HIV-positive people

BACKGROUND

Cryptococcal disease remains one of the main causes of death in HIV-positive people who have low cluster of differentiation 4 (CD4) cell counts. Currently, the World Health Organization (WHO) recommends screening HIV-positive people with low CD4 counts for cryptococcal antigenaemia (CrAg), and treating those who are CrAg-positive. This Cochrane Review examined the effects of an approach where those with low CD4 counts received regular prophylactic antifungals, such as fluconazole.

OBJECTIVES

To assess the efficacy and safety of antifungal drugs for the primary prevention of cryptococcal disease in adults and children who are HIV-positive.

SEARCH METHODS

We searched the CENTRAL, MEDLINE PubMed, Embase OVID, CINAHL EBSCOHost, WHO International Clinical Trials Registry Platform (WHO ICTRP), ClinicalTrials.gov, conference proceedings for the International AIDS Society (IAS) and Conference on Retroviruses and Opportunistic Infections (CROI), and reference lists of relevant articles up to 31 August 2017.

SELECTION CRITERIA

Randomized controlled trials of adults and children, who are HIV-positive with low CD4 counts, without a current or prior diagnosis of cryptococcal disease that compared any antifungal drug taken as primary prophylaxis to placebo or standard care.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility and risk of bias, and extracted and analysed data. The primary outcome was all-cause mortality. We summarized all outcomes using risk ratios (RR) with 95% confidence intervals (CI). Where appropriate, we pooled data in meta-analyses. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

Nine trials, enrolling 5426 participants, met the inclusion criteria of this review. Six trials administered fluconazole, while three trials administered itraconazole.Antifungal prophylaxis may make little or no difference to all-cause mortality (RR 1.07, 95% CI 0.80 to 1.43; 6 trials, 3220 participants; low-certainty evidence). For cryptococcal specific outcomes, prophylaxis probably reduces the risk of developing cryptococcal disease (RR 0.29, 95% CI 0.17 to 0.49; 7 trials, 5000 participants; moderate-certainty evidence), and probably reduces deaths due to cryptococcal disease (RR 0.29, 95% CI 0.11 to 0.72; 5 trials, 3813 participants; moderate-certainty evidence). Fluconazole prophylaxis may make no clear difference to the risk of developing clinically resistant Candida disease (RR 0.93, 95% CI 0.56 to 1.56; 3 trials, 1198 participants; low-certainty evidence); however, there may be an increased detection of fluconazole-resistant Candida isolates from surveillance cultures (RR 1.25, 95% CI 1.00 to 1.55; 3 trials, 539 participants; low-certainty evidence). Antifungal prophylaxis was generally well-tolerated with probably no clear difference in the risk of discontinuation of antifungal prophylaxis compared with placebo (RR 1.01, 95% CI 0.91 to 1.13; 4 trials, 2317 participants; moderate-certainty evidence). Antifungal prophylaxis may also make no difference to the risk of having any adverse event (RR 1.07, 95% CI 0.88 to 1.30; 4 trials, 2317 participants; low-certainty evidence), or a serious adverse event (RR 1.08, 95% CI 0.83 to 1.41; 4 trials, 888 participants; low-certainty evidence) when compared to placebo or standard care.

AUTHORS' CONCLUSIONS

Antifungal prophylaxis reduced the risk of developing and dying from cryptococcal disease. Therefore, where CrAG screening is not available, antifungal prophylaxis may be used in patients with low CD4 counts at diagnosis and who are at risk of developing cryptococcal disease.

Candida Infections and Therapeutic Strategies: Mechanisms of Action for Traditional and Alternative Agents

The Candida genus comprises opportunistic fungi that can become pathogenic when the immune system of the host fails. Candida albicans is the most important and prevalent species. Polyenes, fluoropyrimidines, echinocandins, and azoles are used as commercial antifungal agents to treat candidiasis. However, the presence of intrinsic and developed resistance against azole antifungals has been extensively documented among several Candida species. The advent of original and re-emergence of classical fungal diseases have occurred as a consequence of the development of the antifungal resistance phenomenon. In this way, the development of new satisfactory therapy for fungal diseases persists as a major challenge of present-day medicine. The design of original drugs from traditional medicines provides new promises in the modern clinic. The urgent need includes the development of alternative drugs that are more efficient and tolerant than those traditional already in use. The identification of new substances with potential antifungal effect at low concentrations or in combination is also a possibility. The present review briefly examines the infections caused by Candida species and focuses on the mechanisms of action associated with the traditional agents used to treat those infections, as well as the current understanding of the molecular basis of resistance development in these fungal species. In addition, this review describes some of the promising alternative molecules and/or substances that could be used as anticandidal agents, their mechanisms of action, and their use in combination with traditional drugs.

The synergistic fungicidal effect of low-frequency and low-intensity ultrasound with amphotericin B-loaded nanoparticles on C. albicans in vitro

It is difficult to effectively eradicate C. albicans using traditional antifungal agents, mainly because the low permeability of the C. albicans cell wall creates strong drug resistance. The aim of this study was to investigate the synergistic fungicidal effect and the underlying mechanisms of low-frequency and low-intensity ultrasound combined with a treatment of amphotericin B-loaded nanoparticles (AmB-NPs) against C. albicans. AmB-NPs were prepared by a poly(lactic-co-glycolic acid) (PLGA) double emulsion method. C. albicans was treated by AmB-NPs combined with 42 kHz ultrasound irradiation at an intensity of 0.30 W/cm² for 15 min. The results demonstrate that the application of ultrasound enhanced the antibacterial effectiveness of AmB-NPs (P < 0.01), and the antifungal efficiency increased significantly with increasing AmB concentration of drug-loaded nanoparticles under ultrasonic irradiation. Additionally, the mycelial morphology of C. albicans suffered from the most severe damage and loss of normal microbial morphology after the combined treatment of AmB-NPs and ultrasound, as revealed by electron microscope. Furthermore, we verified the safe use of low-frequency ultrasound on exposed skin and discussed the potential mechanism of ultrasound enhanced fungicidal activity. The results reveal that the mechanism may be associated with the ultrasound cavitation effect and an increase in intracellular reactive oxygen species.

Invasive Fungal Infections in Patients with Hematological Malignancies: Emergence of Resistant Pathogens and New Antifungal Therapies

Invasive fungal infections caused by drug-resistant organisms are an emerging threat to heavily immunosuppressed patients with hematological malignancies. Modern early antifungal treatment strategies, such as prophylaxis and empirical and preemptive therapy, result in long-term exposure to antifungal agents, which is a major driving force for the development of resistance. The extended use of central venous catheters, the nonlinear pharmacokinetics of certain antifungal agents, neutropenia, other forms of intense immunosuppression, and drug toxicities are other contributing factors. The widespread use of agricultural and industrial fungicides with similar chemical structures and mechanisms of action has resulted in the development of environmental reservoirs for some drug-resistant fungi, especially azole-resistant Aspergillus species, which have been reported from four continents. The majority of resistant strains have the mutation TR34/L98H, a finding suggesting that the source of resistance is the environment. The global emergence of new fungal pathogens with inherent resistance, such as Candida auris, is a new public health threat. The most common mechanism of antifungal drug resistance is the induction of efflux pumps, which decrease intracellular drug concentrations. Overexpression, depletion, and alteration of the drug target are other mechanisms of resistance. Mutations in the ERG11 gene alter the protein structure of C-demethylase, reducing the efficacy of antifungal triazoles. Candida species become echinocandin-resistant by mutations in FKS genes. A shift in the epidemiology of Candida towards resistant non-albicans Candida spp. has emerged among patients with hematological malignancies. There is no definite association between antifungal resistance, as defined by elevated minimum inhibitory concentrations, and clinical outcomes in this population. Detection of genes or mutations conferring resistance with the use of molecular methods may offer better predictive values in certain cases. Treatment options for resistant fungal infections are limited and new drugs with novel mechanisms of actions are needed. Prevention of resistance through antifungal stewardship programs is of paramount importance.

Characterization of Herbal Antifungal Agent, Origanum vulgare against Oral Candida spp. Isolated from Patients with Candida-Associated Denture Stomatitis: An In vitro Study

Background:

Candida Associated Denture Stomatitis is the prevalent fungal pathosis in denture wearers, especially in immunocompromized patients. Existing antifungal agents are ineffective since the Candida species become resistant and also, they become toxic. Origanum vulgare is a herbal plant with high anti-fungal activity against Candida of blood and urine origin. However, it has never been explored against Candida from oral cavity.

Materials & Methodology:

Dry leaves of the plant were purchased and authenticated. Oil extraction was done using Hydro-distillation method. Clinical isolates of Candida from denture wearers was speciated using CHROMagar. Well Diffusion test was used to confirm the antifungal activity. Hydro-distillation & Maceration methods of extraction were compared. MIC/MFC was determined using CSLI guidelines. Infra-Red Spectroscopy was used to identify the active functional group.

Results:

O.vulgare showed 30±3mm of zone of inhibition as against 19mm for fluconazole. The suitable extraction method was Hydro-distillation. MIC & MFC were found to be 0.024% and 0.097% respectively which was much lesser than for fluconazole (0.25%). The active functional group had chemically similar structure as Carvacrol, usually found in antifungal herbs.

Conclusion:

within the limitations of the study, it was concluded that (a)O.vulgare is anticandidal for clinical isolates of oral Candida, (b) Hydro-distillation is an effective method as compared to Maceration (c) MIC & MFC are much lower than that of fluconazole (d) the major functional group was structurally similar to Carvacrol.

Recent advances in delivery of antifungal agents for therapeutic management of candidiasis

Candidiasis is a fungal infection caused by yeasts that belong to the genus Candida. There are over twenty species of Candida yeasts that can cause infection in humans, the most common of which is Candida albicans. Candida yeasts normally reside in the intestinal tract and can be found on mucous membranes and skin without causing infection; however, overgrowth of these organisms can cause symptoms to develop. Presence of other diseases that compromises the patient's immunity makes it more difficult to treat. Candidiasis is majorly divided into superficial infections (oral or vaginal) and systemic infections, also known as invasive candidiasis. The conventional therapeutic modalities used to treat candidiasis are associated with several side effects that limits the dose and dosing frequency. Development of novel drug delivery systems for reduction in dose and alleviation of side effects is an important strategy to improve the clinical efficacy and patient acceptability. This review gives a bird's eye view of the classification and current therapeutic regime of candidiasis. It presents the varied types of drug delivery systems that have been exploited for delivery of antifungal agents with measurable benefits. It also touches upon echinocandins a relatively new class of drugs that are amenable for translation into novel dosage forms with application against biofilm producing and fluconazole resistant strains contributing to a better therapeutic management of candidiasis.

Candida species diversity and antifungal susceptibility patterns in oral samples of HIV/AIDS patients in Baja California, Mexico

Candidiasis is the most common opportunistic fungal infection in HIV patients. The aims of this study were to identify the prevalence of carriers of Candida, Candida species diversity, and in vitro susceptibility to antifungal drugs. In 297 HIV/AIDS patients in Baja California, Mexico, Candida strains were identified by molecular methods (PCR-RFLP) from isolates of oral rinses of patients in Tijuana, Mexicali, and Ensenada. 56.3% of patients were colonized or infected with Candida. In Tijuana, there was a significantly higher percentage of carriers (75.5%). Out of the 181 strains that were isolated, 71.8% were Candida albicans and 28.2% were non-albicans species. The most common non-albicans species was Candida tropicalis (12.2%), followed by Candida glabrata (8.3%), Candida parapsilosis (2.2%), Candida krusei (1.7%), and Candida guilliermondii (1.1%). Candida dubliniensis was not isolated. Two associated species were found in 11 patients. In Mexicali and Ensenada, there was a lower proportion of Candida carriers compared to other regions in Mexico and worldwide, however, in Tijuana, a border town with many peculiarities, a higher carrier rate was found. In this population, only a high viral load was associated with oral Candida carriers. Other factors such as gender, use of antiretroviral therapy, CD4+ T-lymphocyte levels, time since diagnosis, and alcohol/ tobacco consumption, were not associated with Candida carriers.

Emerging Infections and Pertinent Infections Related to Travel for Patients with Primary Immunodeficiencies

In today's global economy and affordable vacation travel, it is increasingly important that visitors to another country and their physician be familiar with emerging infections, infections unique to a specific geographic region, and risks related to the process of travel. This is never more important than for patients with primary immunodeficiency disorders (PIDD). A recent review addressing common causes of fever in travelers provides important information for the general population Thwaites and Day (N Engl J Med 376:548-560, 2017). This review covers critical infectious and management concerns specifically related to travel for patients with PIDD. This review will discuss the context of the changing landscape of infections, highlight specific infections of concern, and profile distinct infection phenotypes in patients who are immune compromised. The organization of this review will address the environment driving emerging infections and several concerns unique to patients with PIDD. The first section addresses general considerations, the second section profiles specific infections organized according to mechanism of transmission, and the third section focuses on unique phenotypes and unique susceptibilities in patients with PIDDs. This review does not address most parasitic diseases. Reference tables provide easily accessible information on a broader range of infections than is described in the text.

Changes in In Vitro Susceptibility Patterns of Aspergillus to Triazoles and Correlation With Aspergillosis Outcome in a Tertiary Care Cancer Center, 1999-2015

BACKGROUND

Azole-resistant aspergillosis in high-risk patients with hematological malignancy or hematopoietic stem cell transplantation (HSCT) is a cause of concern.

METHODS

We examined changes over time in triazole minimum inhibitory concentrations (MICs) of 290 sequential Aspergillus isolates recovered from respiratory sources during 1999-2002 (before introduction of the Aspergillus-potent triazoles voriconazole and posaconazole) and 2003-2015 at MD Anderson Cancer Center. We also tested for polymorphisms in ergosterol biosynthetic genes (cyp51A, erg3C, erg1) in the 37 Aspergillus fumigatus isolates isolated from both periods that had non-wild-type (WT) MICs. For the 107 patients with hematologic cancer and/or HSCT with invasive pulmonary aspergillosis, we correlated in vitro susceptibility with 42-day mortality.

RESULTS

Non-WT MICs were found in 37 (13%) isolates and was only low level (MIC <8 mg/L) in all isolates. Higher-triazole MICs were more frequent in the second period and were Aspergillus-species specific, and only encountered in A. fumigatus. No polymorphisms in cyp51A, erg3C, erg1 genes were identified. There was no correlation between in vitro MICs with 42-day mortality in patients with invasive pulmonary aspergillosis, irrespective of antifungal treatment. Asian race (odds ratio [OR], 20.9; 95% confidence interval [CI], 2.5-173.5; P = .005) and azole exposure in the prior 3 months (OR, 9.6; 95% CI, 1.9-48.5; P = .006) were associated with azole resistance.

CONCLUSIONS

Non-WT azole MICs in Aspergillus are increasing and this is associated with prior azole exposure in patients with hematologic cancer or HSCT. However, no correlation of MIC with outcome of aspergillosis was found in our patient cohort.

Plant bioactive molecules bearing glycosides as lead compounds for the treatment of fungal infection: A review

Despite therapeutic advancement in the treatment of fungal infections, morbidity and mortality caused by these infections are still very high. There are approximately 300 fungal species that are infectious and can cause a variety of diseases. At present, several synthetic antifungal drugs are in clinical practice, many of them, however, are vulnerable to multidrug-resistant strains of microbes, and thus compromising the overall treatment outcomes. Glycosides are naturally occurring plant secondary metabolites with important therapeutic potential and clinical utility. The aim of this review was to focus on the antifungal effects of glycosides in preclinical studies with possible mechanism(s) wherein described. Published research show significant susceptibility of different fungi towards phytoglycosides, mediated through multiple mechanisms. Further detailed studies are needed to explain the clinical applications and limitations of these glycosides.

Expression of C-5 sterol desaturase from an edible mushroom in fisson yeast enhances its ethanol and thermotolerance

Bioethanol is an environment friendly and renewable source of energy produced by the fermentation of agricultural raw material by a variety of microorganisms including yeast. Obtaining yeast strains that are tolerant to stresses like high levels of ethanol and high temperature is highly desirable as it reduces cost and increases yield during bioethanol production. Here, we report that heterologous expression of C-5 Sterol desaturase (FvC5SD)-an ergosterol biosynthesis enzyme from an edible mushroom Flammulina velutipes in fission yeast, not only imparts increased thermotolerance but also tolerance towards high ethanol concentration and low pH. This tolerance could be attributed to an increase of ≈1.5 fold in the level of ergosterol and oleic acid (C-18 unsaturated fatty acid) as analysed by gas chromatography- mass spectrometry. FvC5SD is a membrane localized iron binding enzyme that introduces double bond at C-5 position into the Δ7-sterol substrates to yield Δ5, 7- sterols as products. In F. velutipes, FvC5SD transcript was observed to be upregulated by ≈5 fold under low pH condition and by ≈ 9 folds and ≈5 fold at 40°C and 4°C respectively when compared to normal growth temperature of 23°C. Besides, susceptibility to cell wall inhibiting drugs like Congo red and Calcoflour white was also found to increase in FvC5SD expressing S. pombe strain. Alteration in membrane sterol and fatty acid composition could also lead to increase in susceptibility to cell wall inhibiting drugs. Thus, this study has immense industrial application and can be employed to ensure competitiveness of fermentation process.

β-(1,3)-Glucan Unmasking in Some Candida albicans Mutants Correlates with Increases in Cell Wall Surface Roughness and Decreases in Cell Wall Elasticity

Candida albicans is among the most common human fungal pathogens, causing a broad range of infections, including life-threatening systemic infections. The cell wall of C. albicans is the interface between the fungus and the innate immune system. The cell wall is composed of an outer layer enriched in mannosylated glycoproteins (mannan) and an inner layer enriched in β-(1,3)-glucan and chitin. Detection of C. albicans by Dectin-1, a C-type signaling lectin specific for β-(1,3)-glucan, is important for the innate immune system to recognize systemic fungal infections. Increased exposure of β-(1,3)-glucan to the immune system occurs when the mannan layer is altered or removed in a process called unmasking. Nanoscale changes to the cell wall during unmasking were explored in live cells with atomic force microscopy (AFM). Two mutants, the cho1Δ/Δ and kre5Δ/Δ mutants, were selected as representatives that exhibit modest and strong unmasking, respectively. Comparisons of the cho1Δ/Δ and kre5Δ/Δ mutants to the wild type reveal morphological changes in their cell walls that correlate with decreases in cell wall elasticity. In addition, AFM tips functionalized with Dectin-1 revealed that the forces of binding of Dectin-1 to all of the strains were similar, but the frequency of binding was highest for the kre5Δ/Δ mutant, decreased for the cho1Δ/Δ mutant, and rare for the wild type. These data show that nanoscale changes in surface topology are correlated with increased Dectin-1 adhesion and decreased cell wall elasticity. AFM, using tips functionalized with immunologically relevant molecules, can map epitopes of the cell wall and increase our understanding of pathogen recognition by the immune system.

Membrane Proteomics Analysis of the Candida glabrata Response to 5-Flucytosine: Unveiling the Role and Regulation of the Drug Efflux Transporters CgFlr1 and CgFlr2

Resistance to 5-flucytosine (5-FC), used as an antifungal drug in combination therapy, compromises its therapeutic action. In this work, the response of the human pathogen Candida glabrata to 5-FC was evaluated at the membrane proteome level, using an iTRAQ-based approach. A total of 32 proteins were found to display significant expression changes in the membrane fraction of cells upon exposure to 5-FC, 50% of which under the control of CgPdr1, the major regulator of azole drug resistance. These proteins cluster into functional groups associated to cell wall assembly, lipid metabolism, amino acid/nucleotide metabolism, ribosome components and translation machinery, mitochondrial function, glucose metabolism, and multidrug resistance transport. Given the obtained indications, the function of the drug:H+ antiporters CgFlr1 (ORF CAGL0H06017g) and CgFlr2 (ORF CAGL0H06039g) was evaluated. The expression of both proteins, localized to the plasma membrane, was found to confer flucytosine resistance. CgFlr2 further confers azole drug resistance. The deletion of CgFLR1 or CgFLR2 was seen to increase the intracellular accumulation of 5-FC, or 5-FC and clotrimazole, suggesting that these transporters play direct roles in drug extrusion. The expression of CgFLR1 and CgFLR2 was found to be controlled by the transcription factors CgPdr1 and CgYap1, major regulator of oxidative stress resistance.

Future therapies targeted towards eliminating Candida biofilms and associated infections

INTRODUCTION

Candida species are common human commensals and cause either superficial or invasive opportunistic infections. The biofilm form of candida as opposed to its suspended, planktonic form, is predominantly associated with these infections. Alternative or adjunctive therapies are urgently needed to manage Candida infections as the currently available short arsenal of antifungal drugs has been compromised due to their systemic toxicity, cross-reactivity with other drugs, and above all, by the emergence of drug-resistant Candida species due to irrational drug use. Areas covered: Combination anti-Candida therapies, antifungal lock therapy, denture cleansers, and mouth rinses have all been proposed as alternatives for disrupting candidal biofilms on different substrates. Other suggested approaches for the management of candidiasis include the use of natural compounds, such as probiotics, plants extracts and oils, antifungal quorum sensing molecules, anti-Candida antibodies and vaccines, cytokine therapy, transfer of primed immune cells, photodynamic therapy, and nanoparticles. Expert commentary: The sparsity of currently available antifungals and the plethora of proposed anti-candidal therapies is a distinct indication of the urgent necessity to develop efficacious therapies for candidal infections. Alternative drug delivery approaches, such as probiotics, reviewed here is likely to be a reality in clinical settings in the not too distant future.

Persistently Vitreous Culture-Positive Exogenous Fungal Endophthalmitis

PURPOSE

To report the clinical settings, microbiological isolates, and best-corrected visual acuities (BCVA) of patients with persistently culture-positive exogenous fungal endophthlamitis.

DESIGN

Retrospective consecutive case series.

METHODS

Setting: Tertiary referral center.

PATIENT POPULATION

Sixteen eyes of 16 patients with at least 2 consecutive positive vitreous cultures between 1981 and 2015.

INTERVENTIONS

Intravitreal antifungal injection, pars plana vitrectomy (PPV).

MAIN OUTCOME MEASURE

Clinical settings, microbiologic isolates, BCVA.

RESULTS

The most common clinical settings were after cataract surgery (9/16, 56%), glaucoma surgery (4/16, 25%), and trauma (2/16, 13%). The most common single fungal isolate was Candida (4/16, 25%), but 75% of all isolates were molds. Treatment for presumed bacterial endophthalmitis was given initially in 14 patients (88%). All patients underwent a vitrectomy during the course of their treatment, and all received intravitreal or systemic antifungal therapy. The mean initial BCVA was 1.76 ± 0.9 logMAR (Snellen equivalent ≈20/1200), and the mean final BCVA was 1.84 ± 1.2 logMAR (≈20/1400, P = .83). The 9 patients (56%) who had intraocular lens (IOL) and capsular bag removals had better final BCVAs than those who did not (P = .011). The BCVAs were similar in eyes with yeast and mold (P = .37). The visual acuity at the last follow-up was ≥20/40 in 13% (2/16), ≥20/400 in 50% (8/16), and no light perception in 25% (4/16).

CONCLUSIONS

Candida was the single most common isolate, but the majority of isolates were molds. Eyes managed with PPV and removal of the IOL and capsular bag had better visual outcomes. Persistently culture-positive fungal endophthalmitis was associated with poor final visual acuities.

Amphotericin B-copper(II) complex shows improved therapeutic index in vitro

The AmB-Cu(II) complex has recently been reported as an antifungal agent with reduced aggregation of AmB in aqueous solutions, increased anti C. albicans activity and lower toxicity against human cells in vitro. In the present work, investigations of the activity of the AmB-Cu (II) complex against fungal pathogens with varying susceptibility, including C. albicans and C. parapsilosis strains and intrinsically resistant A. niger, and cytotoxicity in normal human dermal fibroblasts (NHDF) in vitro were performed. For better understanding of the mechanism of reduced cytotoxicity and increased fungicidal activity, the influence of the AmB-Cu (II) complex on membrane integrity and accumulation of cellular reactive oxygen species (ROS) and mitochondrial superoxide was compared with that of conventional AmB. In the sensitive C. albicans and C. parapsilosis strains, the AmB-Cu(II) complex showed higher fungicidal activity (the MIC value was 0.35-0.7μg/ml for the AmB-Cu (II) complex, and 0.45-0.9μg/ml for Fungizone) due to increased induction of oxidative damage with rapid inhibition of the ability to reduce tetrazolium dye (MTT). In the NHDF cell line, the CC₅₀ value was 30.13±1.53μg/ml for the AmB-Cu(II) complex and 17.46±1.24μg/ml for (Fungizone), therefore, the therapeutic index (CC₅₀/MIC₉₀) determined in vitro was 86.09-43.04 for the AmB-Cu(II) complex and 38.80-19.40 for Fungizone. The lower cytotoxicity of the AmB-Cu(II) complex in human cells resulted from lower accumulation of cellular and mitochondrial reactive oxygen species. This phenomenon was probably caused by the induction of successful antioxidant defense of the cells. The mechanism of the reduced cytotoxicity of the AmB-Cu(II) complex needs further investigation, but the preliminary results are very promising.

Quinone derivatives isolated from the endolichenic fungus Phialocephala fortinii are Mdr1 modulators that combat azole resistance in Candida albicans

One of the main azole-resistance mechanisms in Candida pathogens is the upregulation of drug efflux pumps, which compromises the efficacy of azoles and results in treatment failure. The combination of azole-antifungal agents with efflux pump inhibitors represents a promising strategy to combat fungal infection. High-throughput screening of 150 extracts obtained from endolichenic fungal cultures led to the discovery that the extract of Phialocephala fortinii exhibits potent activity for the reversal of azole resistance. From P. fortinii cultures, a total of 15 quinone derivatives, comprising 11 new derivatives and 4 known compounds, were obtained. Among these compounds, palmarumycin P3 (3) and phialocephalarin B (8) specifically modulate the expression of MDR1 to inhibit the activity of drug efflux pumps and therefore reverse azole resistance. The present study revealed Mdr1 targeting as an alternative mechanism for the discovery of new agents to fight antifungal drug resistance.

Chitosan Derivatives Active against Multidrug-Resistant Bacteria and Pathogenic Fungi: In Vivo Evaluation as Topical Antimicrobials

The continuous rise of antimicrobial resistance and the dearth of new antibiotics in the clinical pipeline raise an urgent call for the development of potent antimicrobial agents. Cationic chitosan derivatives, N-(2-hydroxypropyl)-3-trimethylammonium chitosan chlorides (HTCC), have been widely studied as potent antibacterial agents. However, their systemic structure-activity relationship, activity toward drug-resistant bacteria and fungi, and mode of action are very rare. Moreover, toxicity and efficacy of these polymers under in vivo conditions are yet to be established. Herein, we investigated antibacterial and antifungal efficacies of the HTCC polymers against multidrug resistant bacteria including clinical isolates and pathogenic fungi, studied their mechanism of action, and evaluated cytotoxic and antimicrobial activities in vitro and in vivo. The polymers were found to be active against both bacteria and fungi (MIC = 125-250 μg/mL) and displayed rapid microbicidal kinetics, killing pathogens within 60-120 min. Moreover, the polymers were shown to target both bacterial and fungal cell membrane leading to membrane disruption and found to be effective in hindering bacterial resistance development. Importantly, very low toxicity toward human erythrocytes (HC₅₀ = >10000 μg/mL) and embryo kidney cells were observed for the cationic polymers in vitro. Further, no inflammation toward skin tissue was observed in vivo for the most active polymer even at 200 mg/kg when applied on the mice skin. In a murine model of superficial skin infection, the polymer showed significant reduction of methicillin-resistant Staphylococcus aureus (MRSA) burden (3.2 log MRSA reduction at 100 mg/kg) with no to minimal inflammation. Taken together, these selectively active polymers show promise to be used as potent antimicrobial agents in topical and other infections.

Antifungal effect of Echinophora platyloba on expression of CDR1 and CDR2 genes in fluconazole-resistant Candida albicans

BACKGROUND

Several studies examined the effect of the Echinophora platyloba extract in treatment of azole-resistant Candida albicans clinical isolates.

OBJECTIVE

We investigated the effect of E. platyloba extract on expression of CDR1 and CDR2 genes in fluconazole-resistant clinical isolates of C. albicans using real-time PCR.

MATERIALS AND METHODS

The crude extract of E. platyloba was obtained using percolation method. Using serial dilution method, different concentrations of extract were achieved. Two hundred microlitres of fungal suspension (10(6) CFU/ml) was added to the media and cultured with different concentrations and then incubated at 37 °C for 48 h. The concentration of extract in the first tube, which inhibited the growth of C. albicans, was recorded as the Minimal Inhibitory Concentration (MIC). In order to analyse the expression of CDR1 and CDR2 genes, RNA was extracted from C. albicans isolates before and after treatment with MIC of E. platyloba using glass beads and the denaturing buffer agents in an RNase-free environment and then the cDNA was synthesised and used for real-time PCR assay.

RESULTS

Twenty of total of 148 isolates were resistant to fluconazole. The MIC and MFC for the alcoholic extract of E. Platyloba were 64 mg/ml and 128 mg/ml, respectively. Real-time PCR results revealed that the mRNA levels of CDR1 and CDR2 genes significantly declined after incubation with E. Platyloba (both p values < 0.001).

CONCLUSION

E. Platyloba is effective in reducing CDR1 and CDR2 expression which in turn plays an important role in fluconazole resistance in Candida species.

Effectiveness of magnetic fluid hyperthermia against Candida albicans cells

Candida albicans is one of the most frequently isolated fungal pathogens causing opportunistic infections in humans. Targeted magnetic fluid hyperthermia (MFH) is a promising method in thermal therapy facilitating selective heating of pathogen cells like C. albicans. In the paper, we used meso-2,3-dimercaptosuccinic acid (DMSA)-coated magnetic nanoparticles (MNPs) and functionalised anti-C. albicans immunomagnetic nanoparticles (IMNPs) to investigate the potential of MFH in combating C. albicans cells in vitro. Using Mössbauer spectroscopy it was found that synthesised MNPs exhibited superparamagnetic phenomena. On the basis of calorimetric experiments, the maximum SAR (specific absorption rate) was found and a proper concentration of MNPs was established to control the temperature. MFH based on both DMSA-coated MNPs and functionalised anti-C. albicans IMNPs was more effective in combating C. albicans cells in vitro than thermostat hyperthermia. Especially promising results were obtained using functionalised IMNPs, which eradicated most of the pathogen colonies at the temperature of 43 °C.

Homology model, molecular dynamics simulation and novel pyrazole analogs design of Candida albicans CYP450 lanosterol 14 α-demethylase, a target enzyme for antifungal therapy

Candida albicans infections and their resistance to clinically approved azole drugs are major concerns for human. The azole antifungal drugs inhibit the ergosterol synthesis by targeting lanosterol 14α-demethylase of cytochrome P450 family. The lack of high-resolution structural information of fungal pathogens has been a barrier for the design of modified azole drugs. Thus, a preliminary theoretical molecular dynamic study is carried out to develop and validate a simple homologous model using crystallographic structure of the lanosterol 14α-demethylase of Mycobacterium tuberculosis (PDB ID-1EA1) in which the active site residues are substituted with that of C. albicans (taxid 5476). Further, novel designed pyrazole analogs (SGS1-16) docked on chimeric 1EA1 and revealed that SGS-16 show good binding affinity through non-bonding interaction with the heme, which is different from the leading azole antifungals. The ADME-T results showed these analogs can be further explored in design of more safe and effective antifungal agents.

Design, Synthesis and Antifungal Activity of Novel Benzofuran-Triazole Hybrids

A series of novel benzofuran-triazole hybrids was designed and synthesized by click chemistry, and their structures were characterized by HRMS, FTIR and NMR. The in vitro antifungal activity of target compounds was evaluated using the microdilution broth method against five strains of pathogenic fungi. The result indicated that the target compounds exhibited moderate to satisfactory activity. Furthermore, molecular docking was performed to investigate the binding affinities and interaction modes between the target compound and N-myristoyltransferase. Based on the results, preliminary structure activity relationships (SARs) were summarized to serve as a foundation for further investigation.

Anti- Sporothrix spp. activity of medicinal plants

ABSTRACT Cases of sporotrichosis in humans and animals without satisfactory clinical response have increased, a warning sign of strains resistant to conventional antifungal agents. The urgent search for alternative therapies was an incentive for research on medicinal plants with anti-Sporothrix spp. properties. A bibliographic survey was performed based on scientific papers about in vitro and in vivo antifungal activity of essential oils and extracts of plants in differents solvents against the fungal of the Sporothrix schenckii complex. The study methodology consisted of a literature review in Google Scholar, Science Direct, Pubmed, Bireme and Springer link with papers from 1986 to 2015. We found 141 species of plants that were investigated, of which 100 species were concentrated in 39 botanical families that had confirmed anti-Sporothrix activity. Combretaceae, Asteraceae and Lamiaceae represented the botanical families with the greatest number of plants species with antifungal potential, using different methodologies. However, there are few studies with medicinal plants in experimental infection in animals that prove their activity in the treatment of sporotrichosis. It reinforces the need for further research related to standardization of in vitro methodologies and in vivo studies related to safety and to toxicity potential of these plants with anti-Sporothrix spp. activity.

Cytopiloyne, a polyacetylenic glucoside from Bidens pilosa, acts as a novel anticandidal agent via regulation of macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Bidens pilosa, a tropical and sub-tropical herbal plant, is used as an ethnomedicine for bacterial infection or immune modulation in Asia, America and Africa. It has been demonstrated that cytopiloyne (CP), a bioactive polyacetylenic glucoside purified from B. pilosa, increases the percentage of macrophages in the spleen but the specific effects on macrophages remain unclear.

AIM OF THE STUDY

The aim of this study was to evaluate the effects of CP on macrophage activity and host defense in BALB/c mice with Candida parapsilosis infection and investigate the likely mechanisms.

MATERIALS AND METHODS

RAW264.7 cells, a mouse macrophage cell line, were used to assess the effects of CP on macrophage activity by phagocytosis assay, colony forming assay and acridine orange/crystal violet stain. To evaluate the activity of CP against C. parapsilosis, BALB/c mouse infection models were treated with/without CP and histopathological examination was performed. The role of macrophages in the infection model was clarified by treatment with carrageenan, a selective macrophage-toxic agent. RAW264.7 macrophage activities influenced by CP were further investigated by lysosome staining, phagosomal acidification assay, lysosome enzyme activity and PKC inhibitor GF109203X.

RESULTS

The results showed that CP in vitro enhances the ability of RAW264.7 macrophages to engulf and clear C. parapsilosis. In the mouse model, CP treatment improved the survival rate of Candida-infected mice and lowered the severity of microscopic lesions in livers and spleens via a macrophage-dependent mechanism. Furthermore, with CP treatment, the fusion and acidification of phagolysosomes were accelerated and the lysosome enzyme activity of RAW264.7 macrophages was elevated. PKC inhibitor GF109203X reversed the increase in phagocytic activity by CP demonstrating that the PKC pathway is involved in the macrophage-mediated phagocytosis of C. parapsilosis.

CONCLUSIONS

Our data suggested that CP, as an immunomodulator, enhances macrophage activity against C. parapsilosis infections.

Antifungal susceptibility of 175 Aspergillus isolates from various clinical and environmental sources

Some environmental Aspergillus spp. isolates have been described as resistant to antifungals, potentially causing an emerging medical problem. In the present work, the antifungal susceptibility profile of 41 clinical and 134 environmental isolates of Aspergillus was determined using the CLSI microdilution method. The aim of this study was to compare environmental and clinical isolates with respect to their susceptibility, and assess the potential implications for therapy of isolates encountered in different environments. To our knowledge, this is the first report comparing antifungal susceptibility profiles of Aspergillus collected from different environmental sources (poultries, swineries, beach sand, and hospital environment). Significant differences were found in the distribution of the different species sections for the different sources. Significant differences were also found in the susceptibility profile of the different Aspergillus sections recovered from the various sources. Clear differences were found between the susceptibility of clinical and environmental isolates for caspofungin, amphotericin B and posaconazole, with clinical isolates showing overall greater susceptibility, except for caspofungin. In comparison to clinical isolates, hospital environmental isolates showed significantly less susceptibility to amphotericin B and posaconazole. These data indicate that species section identity and the site from which the isolate was recovered influence the antifungal susceptibility profile, which may affect initial antifungal choices.

Exploration of anti-Malassezia potential of Nyctanthes arbor-tristis L. and their application to combat the infection caused by Mala s1 a novel allergen

Background

Malassezia commensal yeasts along with multitude of antigens have been found to be associated with various skin disorders including Pityriasis versicolor (PV). Amongst them Mala s1, a 37 kDa protein has been proved to be a major allergen reacting with a large panel of sera. However, there exists no therapeutic alternative to combat such problems in form of plant based natural compounds. The purpose of this study is in the first place, to determine the anti-Malassezia activity of Nyctanthes arbor-tristis L. (NAT) ethanolic leaf extract through turbidimetric growth curves, disruption of plasma membrane and secondly, it aims to present in silico validation of its active constituents over Mala s1a novel allergen.

Methods

The antifungal susceptibility 50 % ethanolic extract of NAT was determined by broth microdilution method according to CLSI guidelines. Further MICs and IC₅₀ were determined spectrophotometrically using the software SoftMax® Pro-5 (Molecular Devices, USA). Active constituents mediated disruption of plasma membrane was studied through flowcytometry by permeabilization of fluorescent dye Propidium Iodide (PI). Antioxidant activity of the extract was determined using the DPPH stable radical. Molecular validation of fungal DNA from the extract was observed using PCR amplification. In silico analysis of its active constituents over Mala s1 was performed using HEX software and visualized through Pymol.

Results

The anti-Malassezia potential of NAT leaf extracts reflected moderate MIC 1.05 μg/μl against M. globosa, while least effective against M. restricta with MIC 1.47 μg/μl. A linear correlation coefficient R² = 0.866 was obtained in case of M. globosa while minimum was observed in M. restricta with R² = 0.732. The flow cytometric data reveal ~ 75 % cell death when treated with active constituents β-Sitosterol and Calceolarioside A. The docking confirmations and the interaction energies between Mala s1 and the active constituents (β-Sitosterol and Calceolarioside A) from extracts showed an effective binding which suggests Mala s1 as efficient allergen for site specific targeting.

Conclusions

This study revealed that Nyctanthes arbor-tristis L. (NAT) extracts possess high anti-Malassezia potential which is driven mainly by disruption of plasma membrane. Also in silico validation and molecular modeling studies establishes Mala s1 as a novel allergen that could be a potential target in disease treatment. Our results would also provide a foundation for the development of new therapeutic approach using NAT extract as lead compound with high antioxidant property as an added trait for skin care.

Lysine enhances the effect of amphotericin B against Candida albicans in vitro

Amphotericin B (AmB) is a polyene antibiotic produced by Streptomyces nodosus and has been used for >50 years in the treatment of acute systemic fungal infections. In the present study, we demonstrated that lysine, an essential amino acid, could enhance the effect of AmB against Candida albicans in vitro, although lysine itself did not exert a fungicidal effect. In addition, the combination of AmB with lysine could provide an enhanced action against Candida parapsilosis and Cryptococcus neoformans compared with AmB alone. Lysine could also enhance the antifungal effect of caspofungin or nystatin. An enhanced effect of the combination of lysine with AmB was observed for the prevention of biofilm and hypha formation. Furthermore, our results demonstrated that lysine-mediated oxidative damage, such as the generation of endogenous reactive oxygen species, may be the mechanism underlying the enhancing effect of lysine on AmB. Our results also showed that CaMCA1 gene plays an important role in increasing the sensitivity of C. albicans cells upon AmB treatment. Using AmB together with lysine may be a promising strategy for the therapy of disseminated candidiasis.

Facile synthesis of new N-sulfonamidyl-4-thiazolidinone derivatives and their biological evaluation

A one-pot three-component facile synthesis of N-sulfonamidyl-4-thiazolidinone derivatives using a [HDBU][HSO₄] reusable ionic liquid was carried out, together with an investigation into their antifungal and antioxidant properties and a molecular docking study.

Antifungal effect and action mechanism of antimicrobial peptide polybia-CP

The incidence of life-threatening invasive fungal infections increased significantly in recent years. However, the antifungal therapeutic options are very limited. Antimicrobial peptides are a class of potential lead chemical for the development of novel antifungal agents. Antimicrobial peptide polybia-CP was purified from the venom of the social wasp Polybia paulista. In this study, we synthesized polybia-CP and determined its antifungal effects against a series of Candidian species. Our results showed that polybia-CP has potent antifungal activity and fungicidal activity against the tested fungal cells with a proposed membrane-active action mode. In addition, polybia-CP could induce the increase of cellular reactive oxygen species production, which would attribute to its antifungal activity. In conclusion, the present study suggests that polybia-CP has potential as an antifungal agent or may offer a new strategy for antifungal therapeutic option.

Identification of New Antifungal Compounds Targeting Thioredoxin Reductase of Paracoccidioides Genus

The prevalence of invasive fungal infections worldwide has increased in the last decades. The development of specific drugs targeting pathogenic fungi without producing collateral damage to mammalian cells is a daunting pharmacological challenge. Indeed, many of the toxicities and drug interactions observed with contemporary antifungal therapies can be attributed to “nonselective” interactions with enzymes or cell membrane systems found in mammalian host cells. A computer-aided screening strategy against the TRR1 protein of Paracoccidioides lutzii is presented here. Initially, a bank of commercially available compounds from Life Chemicals provider was docked to model by virtual screening simulations. The small molecules that interact with the model were ranked and, among the best hits, twelve compounds out of 3,000 commercially-available candidates were selected. These molecules were synthesized for validation and in vitro antifungal activity assays for Paracoccidioides lutzii and P. brasiliensis were performed. From 12 molecules tested, 3 harbor inhibitory activity in antifungal assays against the two pathogenic fungi. Corroborating these findings, the molecules have inhibitory activity against the purified recombinant enzyme TRR1 in biochemical assays. Therefore, a rational combination of molecular modeling simulations and virtual screening of new drugs has provided a cost-effective solution to an early-stage medicinal challenge. These results provide a promising technique to the development of new and innovative drugs.

Heat Shock Protein 90 (Hsp90) as a Molecular Target for the Development of Novel Drugs Against the Dermatophyte Trichophyton rubrum

Treatment of fungal infections is difficult due to several reasons, such as side effects of drugs, emergence of resistant strains, and limited number of molecular targets for the drug compounds. In fungi, heat shock proteins (Hsps) have been implicated in several processes with the conserved molecular chaperone Hsp90 emerging as a potential target for antifungal therapy. It plays key cellular roles by eliciting molecular response to environmental changes, morphogenesis, antifungal resistance, and fungal pathogenicity. Here, we evaluated the transcription profiles of hsp genes of the most prevalent dermatophyte Trichophyton rubrum in response to different environmental challenges including nutrient availability, interaction with cells and molecules of the host tissue, and drug exposure. The results suggest that each Hsp responds to a specific stress condition and that the cohort of Hsps facilitates fungal survival under various environmental challenges. Chemical inhibition of Hsp90 resulted in increased susceptibility of the fungus to itraconazole and micafungin, and decreased its growth in human nails in vitro. Moreover, some hsp and related genes were modulated by Hsp90 at the transcriptional level. We are suggesting a role of Hsp90 in the pathogenicity and drug susceptibility of T. rubrum as well as the regulation of other Hsps. The synergism observed between the inhibition of Hsp90 and the effect of itraconazole or micafungin in reducing the fungal growth is of great interest as a novel and potential strategy to treat dermatophytoses.

In Vitro Susceptibilities of Candida albicans Isolates to Antifungal Agents in Tokat, Turkey

Background:

Candida albicans is the pathogenic species most commonly isolated from fungal infections. Management of these infections depends on the immune status of the host, severity of disease, and the choice of antifungal drug. In spite of the development of new antifungal drugs, epidemiological studies have shown that resistance to antifungal drugs in C. albicans strains is becoming a serious problem.

Objectives:

The aim of this study was to evaluate the in vitro susceptibility of C. albicans isolates to ketoconazole, fluconazole, itraconazole, voriconazole, posaconazole, amphotericin B, caspofungin, and anidulafungin.

Materials and Methods:

A total of 201 C. albicans isolates were collected from clinical specimens. Antifungal susceptibility tests were performed using the Etest.

Results:

All the tested C. albicans isolates were found to be susceptible to amphotericin B and anidulafungin. Although none of the isolates showed resistance to caspofungin, 15% of the isolates were classified as showing intermediate resistance. The resistance rates of C. albicans isolates to ketoconazole, fluconazole, itraconazole, voriconazole and posaconazole were 32%, 34%, 21%, 14% and 14%, respectively.

Conclusions:

Our findings indicate that resistance of C. albicans strains to azoles is more common in Tokat, Turkey. Therefore, a strategy to control the inappropriate and widespread use of antifungal drugs is urgently needed. Fungal culturing and antifungal susceptibility testing will be useful in patient management as well as resistance surveillance.

In Vitro Susceptibilities of Candida albicans Isolates to Antifungal Agents in Tokat, Turkey

BACKGROUND

Candida albicans is the pathogenic species most commonly isolated from fungal infections. Management of these infections depends on the immune status of the host, severity of disease, and the choice of antifungal drug. In spite of the development of new antifungal drugs, epidemiological studies have shown that resistance to antifungal drugs in C. albicans strains is becoming a serious problem.

OBJECTIVES

The aim of this study was to evaluate the in vitro susceptibility of C. albicans isolates to ketoconazole, fluconazole, itraconazole, voriconazole, posaconazole, amphotericin B, caspofungin, and anidulafungin.

MATERIALS AND METHODS

A total of 201 C. albicans isolates were collected from clinical specimens. Antifungal susceptibility tests were performed using the Etest.

RESULTS

All the tested C. albicans isolates were found to be susceptible to amphotericin B and anidulafungin. Although none of the isolates showed resistance to caspofungin, 15% of the isolates were classified as showing intermediate resistance. The resistance rates of C. albicans isolates to ketoconazole, fluconazole, itraconazole, voriconazole and posaconazole were 32%, 34%, 21%, 14% and 14%, respectively.

CONCLUSIONS

Our findings indicate that resistance of C. albicans strains to azoles is more common in Tokat, Turkey. Therefore, a strategy to control the inappropriate and widespread use of antifungal drugs is urgently needed. Fungal culturing and antifungal susceptibility testing will be useful in patient management as well as resistance surveillance.