Treatment Of Candida Infections Research Articles

Menthol as an effective inhibitor of quorum sensing and biofilm formation in Candida albicans and Candida glabrata by targeting the transcriptional repressor TUP1.

Menthol, a natural quorum sensing molecule, is derived from the Mentha species. Combating pathogenicity by inactivating quorum sensing is an emerging approach. Therefore, our objective was to investigate anti-quorum sensing and anti-biofilm potentials of menthol in Candida albicans and Candida glabrata. The antifungal properties of menthol were evaluated using a broth microdilution assay and a time-kill assay, and its effects on quorum sensing-mediated virulence factors, cellular reactive oxygen species (ROS), and biofilm formation were tested by evaluating TUP1 expression levels in both C. albicans and C. glabrata. Quorum sensing-mediated virulence factors and biofilm formation were inhibited by menthol in both C. albicans and C. glabrata. Furthermore, coinciding with elevated ROS levels, mRNAs of the quorum sensing-related gene TUP1 were upregulated in both C. albicans and C. glabrata. This study highlights the anti-quorum sensing potential of menthol through the inhibition of quorum sensing-mediated virulence factors, ROS generation, and biofilm development by targeting TUP1, which could have potential in the treatment of Candida infections.

Impact of Obesity on Echinocandin Effectiveness in Treating Candida Infections: A Retrospective Observational Cohort Study.

Echinocandins are used to treat invasive candidiasis (IC), with FDA-approved doses indicated for both obese and non-obese patients. Pharmacokinetic (PK) studies have identified subtherapeutic exposure in obese patients receiving standard doses (SDs) of echinocandins. However, research on clinical outcome differences of echinocandins' SDs between obese and non-obese patients is lacking. Therefore, this study aimed to evaluate the effectiveness of echinocandins' SDs in obese compared to normal-weight patients with IC. This retrospective cohort study was conducted at King Saud University Medical City (KSUMC) from Jan 2017 to Feb 2023. The study included adult patients diagnosed with Candida infections who received ≥ 4 doses of echinocandins. Patients with body mass index (BMI) less than 18 kg/m2 were excluded from the study. The primary and secondary outcomes included the total length of stay (LOS), IC duration, frequency of clinical resolution and all-cause mortality. This study included 132 patients (47 obese; 85 non-obese) with a median age of 61 years. The median BMI and weight were different between the obese (34.5 kg/m2, 88 kg) and non-obese (24 kg/m2, 65 kg) groups (P= 0.01). Micafungin and caspofungin were used in 63.6% and 36.4% of patients, respectively. The total LOS and length of IC infections were similar between both groups, with median values of 29.5 days (P= 0.896) and 18 days (P = 0.160), respectively. The clinical improvement percentages were 68.1% for obese and 65.9% for non-obese patients (P= 0.797), with all-cause mortality rates at 44.7% and 42.4%, respectively (P= 0.796). The study found no clinical outcome differences between obese and non-obese patients, with Similar effectiveness of the echinocandins' SDs in both groups. Further research in multi-centre settings is recommended to detect any potential differences between the two groups.

Candida glabrata maintains two Hap1 homologs, Zcf27 and Zcf4, for distinct roles in ergosterol gene regulation to mediate sterol homeostasis under azole and hypoxic conditions.

Candida glabrata exhibits innate resistance to azole antifungal drugs but also has the propensity to rapidly develop clinical drug resistance. Azole drugs, which target Erg11, is one of the three major classes of antifungals used to treat Candida infections. Despite their widespread use, the mechanism controlling azole-induced ERG gene expression and drug resistance in C. glabrata has primarily revolved around Upc2 and/or Pdr1. In this study, we determined the function of two zinc cluster transcription factors, Zcf27 and Zcf4, as direct but distinct regulators of ERG genes. Our phylogenetic analysis revealed C. glabrata Zcf27 and Zcf4 as the closest homologs to Saccharomyces cerevisiae Hap1. Hap1 is a known zinc cluster transcription factor in S. cerevisiae in controlling ERG gene expression under aerobic and hypoxic conditions. Interestingly, when we deleted HAP1 or ZCF27 in either S. cerevisiae or C. glabrata, respectively, both deletion strains showed altered susceptibility to azole drugs, whereas the strain deleted for ZCF4 did not exhibit azole susceptibility. We also determined that the increased azole susceptibility in a zcf27Δ strain is attributed to decreased azole-induced expression of ERG genes, resulting in decreased levels of total ergosterol. Surprisingly, Zcf4 protein expression is barely detected under aerobic conditions but is specifically induced under hypoxic conditions. However, under hypoxic conditions, Zcf4 but not Zcf27 was directly required for the repression of ERG genes. This study provides the first demonstration that Zcf27 and Zcf4 have evolved to serve distinct roles allowing C. glabrata to adapt to specific host and environmental conditions.

The TAC1 Gene in Candida albicans: Structure, Function, and Role in Azole Resistance: A Mini-Review.

Candidiasis is a common fungal infection caused by Candida species, with Candida albicans being the most prevalent. Resistance to azole drugs, commonly used to treat Candida infections, poses a significant challenge. Transcriptional activator candidate 1 (TAC1) gene has emerged as a key player in regulating drug resistance in C. albicans. This review explores the structure and function of the TAC1 gene and its role in azole resistance. This gene encodes a transcription factor that controls the expression of genes involved in drug resistance, such as efflux pump genes (CDR1, CDR2, and MDR1) and ERG11. Mutations in TAC1 can increase these genes' expression and confer resistance to azoles. Various TAC1 gene mutations, mostly gain-of-function mutations, have been identified, which upregulate CDR1 and CDR2 expression, resulting in azole resistance. Understanding the mechanisms of azole resistance mediated by the TAC1 gene is crucial for the strategies in the effective antifungal development pipeline.

Manganese(II), copper(II) and silver(I) complexes containing 1,10-phenanthroline/1,10-phenanthroline-5,6-dione against Candida species.

Background: New chemotherapeutics are urgently required to treat Candida infections caused by drug-resistant strains. Methods: The effects of 16 1,10-phenanthroline (phen)/1,10-phenanthroline-5,6-dione/dicarboxylate complexed with Mn(II), Cu(II) and Ag(I) were evaluated against ten different Candida species. Results: Proliferation of Candida albicans, Candida dubliniensis, Candida famata, Candida glabrata, Candida guilliermondii, Candida kefyr, Candida krusei, Candida lusitaniae, Candida parapsilosis and Candida tropicalis was inhibited by three of six Cu(II) (MICs 1.52-21.55μM), three of three Ag(I) (MICs 0.11-12.74μM) and seven of seven Mn(II) (MICs 0.40-38.06μM) complexes. Among these [Mn2(oda)(phen)4(H2O)2][Mn2(oda)(phen)4(oda)2].4H2O, where oda=octanedioic acid, exhibited effective growth inhibition (MICs 0.4-3.25μM), favorable activity indexes, low toxicity against Vero cells and good/excellent selectivity indexes (46.88-375). Conclusion: [Mn2(oda)(phen)4(H2O)2][Mn2(oda)(phen)4(oda)2].4H2O represents a promising chemotherapeutic option for emerging, medically relevant and drug-resistant Candida species.

Возможности применения препаратов рекомбинантного интерферона α-2b в комплексной терапии кандидозной инфекции слизистых оболочек у пациентов групп риска

Background: despite the availability of various antifungal medications, achieving complete relief of fungal infections can be challenging, particularly in cases where Candida spp. exhibit resistance to antimycotic agents or in patients who are at increased risk of developing candidiasis, such as those with immunosuppression, decompensated diabetes mellitus, or undergoing prolonged antibacterial treatment. The limited success of antifungal monotherapy in treating candida infections highlights the necessity for alternative treatment tactics. Aim: this study aims to assess the impact of recombinant interferon α-2b combined with antioxidants, administered as rectal suppositories, on extending the relapse-free period in high-risk patients following successful antifungal treatment of oral and genital mucosal candidiasis. Patients and Methods: the study comprised 50 patients with different forms of oral and genital mucosal candidiasis, all having insulin- independent diabetes mellitus and suboptimal glycated hemoglobin levels. Initial antifungal treatment involved drugs from the imidazole or triazole groups. Patients were then randomized into two cohorts: one receiving recombinant interferon α-2b with antioxidants (n=17) and the other receiving a placebo (n=18). Clinical outcomes and microbial content of Candida fungi were evaluated pre- and post-treatment. Results: the median age of participants was 55.5 years, with females constituting 56% (28 patients) of the cohort. Vulvovaginal candidiasis was the most prevalent diagnosis, affecting 42% of patients. The initial mean microbial load of Candida was 1.4×105 CFU/ml. Post initial antifungal treatment, 70% (35 patients) exhibited full symptom regression and marked reduction in CFU levels. The group treated with interferon α-2b experienced a mean clinical remission duration of 53.6±7.5 days, with 76.5% (13 patients) maintaining remission throughout the 60-day follow-up and CFU levels dropping below 1×103. In contrast, the placebo group had a mean remission duration of 30.1±9.6 days post- antimycotic therapy. Conclusion: integrating recombinant interferon α-2b with antioxidants into the treatment regimens for oral and genital mucosal candidiasis in high-risk patients significantly extends clinical remission periods. These findings suggest that this combination therapy could be a promising option for rehabilitation and potentially preventive interventions for patients susceptible to candida infections. KEYWORDS: Candida spp., mucosal candidiasis, diabetes mellitus, interferon alpha-2b. FOR CITATION: Zlobin D.E., Gureeva M.A., Molochkov A.V., Misnikova I.V., Polesko I.V., Guseva T.S. Possibilities of recombinant interferon α-2b drugs in the complex therapy of mucosal candidiasis infection in patients at risk. Russian Medical Inquiry. 2024;8(7):433–438 (in Russ.). DOI: 10.32364/2587-6821-2024-8-7-10.

Investigation of Luliconazole-Loaded Mucoadhesive Electrospun Nanofibers for Anticandidal Activity in the Management of Vaginal Candidiasis.

In this study, we fabricated and evaluated luliconazole-loaded electrospun nanofibers for anticandidal activity in the management of vaginal candidiasis. Polycaprolactone (PCL)/gelatin nanofibers were designed by the electrospinning technique, and the Box-Behnken design (BBD) was adopted for optimization to get tailored fibers. The luliconazole (LCZ) drug was mixed into different concentrations (2.5, 5, 7.5, and 10%) of tea tree oil (TT oil) and loaded into the PCL/gelatin nanofibrous mats. The effective anticandidal potential of nanofiber samples were analyzed by the disk-diffusion method. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), XRD analysis, and in silico study were performed. The entrapment efficiency, swelling degree, mechanical strength, contact angle, mucoadhesion, drug release, and permeation study were assessed. The average diameter of the PCL/gelatin-optimized nanofiber was 153 nm. SEM reflected that the fabricated nanofibers were uniform and bead-free. FTIR and DSC analyzed the interaction and physical entrapment of the drug in the polymeric fibers. The entrapment efficiency of the drug-loaded nanofiber was found to be 89.2 ± 0.8%. Maximum swelling percentages at 4 h were 40.8, 18.9, and 14.0% and contact angles were 46.5°, 62.95°, and 65.78° for the blank, TT oil-loaded, and drug-loaded nanofiber, respectively, which indicated the hydrophilic nature of the fibers. The drug-loaded nanofiber had a high tensile strength with satisfactory mucoadhesive property that led to its adhesion to the vaginal mucosa with no tear. The drug-loaded nanofiber had a cumulative drug release of 67.7 ± 3.4% in 48 h, and the 12.8 ± 0.53 mm of zone of inhibition (ZOI) in 48 h illustrated an effective anticandidal activity. The TT oil-loaded nanofiber also exhibited a small ZOI of 4.3 ± 0.30 mm, indicating a synergistic effect to the antifungal activity of the drug-loaded nanofiber. LCZ-loaded nanofibers can emerge as a novel approach for vaginal drug delivery in the treatment of candida infection. Thus, this pharmaceutical investigation can help in formulating preclinical and clinical models.

Antifungal Effectiveness Test of Cinnamon Extract (Cinnamomum Burmannii) Against Candida Albicans

Background: Candida albicans, is a normal flora that lives on the oral mucosa, digestive tract and vagina. Candida albicans can cause infection such as oral candidiasis. A number of antifungal agents are widely used in the treatment of Candida infections, but some antifungal drugs sometimes have unpleasant side effects. This prompted researchers to examine the contents of natural ingredients that have antifungal activity, one of which is cinnamon. Cinnamon (Cinnamomum burmannii) contains several chemical compounds including cinnamaldehyde and eugenol which are components that have antifungal effects. Objective: to analyze the effectiveness of cinnamon (Cinnamomum burmannii) antifungal against Candida albicans. Materials and Methods: The research was performed as laboratory experiment that calculates the diameter of inhibition using the agar-well diffusion method. 25 samples tested were Candida albicans cultured in SDA (Saboroud Dextrose Agar) medium. Variations in treatment concentrations were cinnamon extract (Cinnamomum burmannii) 25%, 50%, 75%, nystatin oral suspension (positive control), and aquades (negative control). Results: The average inhibition of 75% cinnamon extract (Cinnamomum burmannii) was 16.8 mm, whereas in the positive control nystatin oral suspension was 13.4 mm. The hypothesis test has a value of p=0.000 (p<0.05). Conclusion: There is an antifungal effectiveness of cinnamon (Cinnamomum burmannii) against Candida albicans at a concentration of 75%.

Spectrum and functional properties of <i>ERG11</i> gene mutations in fluconazole-resistant <i>Candida albicans</i> strains isolated from HIV-infected patients

Rationale. The low efficacy of azole antimycotics in treatment of Candida infections, especially in HIV-infected patients, is often associated with overexpression of the ERG11 gene in Candida spp., which results in increased production of ergosterol the target of the above antimycotic drugs. Researchers have found ERG11 gene mutations that can modify its overexpression effects by increasing or decreasing it. However, the findings reported by different laboratories and countries are highly contradictory.
 The purpose of the study is to explore the spectrum and functional properties of ERG11 gene mutations in fluconazole-resistant Candida albicans strains isolated from HIV-infected patients.
 Materials and methods. The study was performed using 10 C. albicans strains inherently resistant to fluconazole and voriconazole and isolated from the oropharynx of HIV-infected patients; the strains were provided from the collection of the Gabrichevsky Moscow Research Institute of Epidemiology and Microbiology. The strains were assessed by their sensitivity to antimycotic agents: anidulafungin, micafungin, caspofungin, posaconazole, voriconazole, itraconazole, fluconazole, amphotericin B, 5-flucytosine. Expression levels of the ERG11 gene were measured by quantitative PCR. ERG11 gene mutations were identified by Sanger sequencing.
 Results. Five mutations (E266D, G464S, I471L, D116E, and V488I) were detected in the ERG11 gene in seven C. albicans strains; six strains carried non-associated co-occurring mutations. Increased expression of the ERG11 gene was found in six C. albicans strains. The V488I mutation demonstrated a strong negative association with the increased expression of the ERG11 gene (r = 0.845; p 0.05). The minimum inhibitory concentration (MIC) in strains carrying mutations was a hundred times as low (p 0.05) as MIC in strains without mutations. In mutation carriers, posaconazole and itraconazole MICs were on average 16.5 times as low as MICs of voriconazole and fluconazole (p 0.001). The presence of mutations in the ERG11 gene had almost no effect on MICs of the tested antimycotics of the echinocandin, polyene, and pyrimidine groups.
 Conclusion. Multiple mutations were detected in the ERG11 gene in most of the C. albicans strains isolated from HIV-infected patients and resistant to fluconazole and voriconazole. Except for the V488I mutation, the detected mutations were not associated with the overexpression of the ERG11 gene and decreased the effects of overexpression of the ERG11 gene by up to 100 times, though they did not eliminate the inherent resistance to triazole antimycotics.

Identification of potent anti-Candida metabolites produced by the soft coral associated Streptomyces sp. HC14 using chemoinformatics

Candida albicans is the most common pathogen responsible for both spontaneous and recurrent candidiasis. The available treatment of Candida infections has several adverse effects, and the development of new drugs is critical. The current study looked at the synthesis of anti-Candida metabolites by Streptomyces sp. HC14 recovered from a soft coral. Using the Plackett Burman design, the medium composition was formulated to maximize production. Using GC–MS, the compounds have been identified, and a cheminformatics approach has been used to identify the potential source of activity. The compounds that showed high potential for activity were identified as pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(phenylmethyl)-3 and di-n-octyl based on their docking score against the cytochrome monooxygenase (CYP51) enzyme in Candida albicans. As a result of their discovery, fewer molecules need to be chemically synthesized, and fermentation optimization maximizes their synthesis, providing a strong foundation for the development of novel anti-Candida albicans agents.

Antimicrobial Peptides: Avant-Garde Antifungal Agents to Fight against Medically Important Candida Species

Expanding the antifungal drug arsenal for treating Candida infections is crucial in this era of the rising life expectancy of patients with immunosuppression and comorbidities. Infections caused by Candida species are on the rise, including those caused by multidrug-resistant strains or species, and the list of antifungals approved for the treatment of these infections is still limited. Antimicrobial peptides (AMPs) are short cationic polypeptides whose antimicrobial activity is under intense investigation. In this review, we present a comprehensive summary of the AMPs with anti-Candida activity that have undergone successful preclinical or clinical trials. Their source, mode of action, and animal model of infection (or clinical trial) are presented. In addition, as some of these AMPs have been tested in combination therapy, the advantages of this approach, as well as the studied cases that have used AMPs and other drugs concomitantly to fight Candida infections, are described.

Rational design, synthesis, antifungal evaluation and docking studies of antifungal peptide CGA-N12 analogues based on the target CtKRE9

Candida tropicalis is a major non-albicans species that causes invasive candidiasis. CGA-N12, an anti-Candida peptide found by our group, disrupted cell wall architecture by inhibiting the activity of the protein killer-resistant 9 (KRE9), a β-1,6-glucan synthase specific to Candida spp. and plants. Herein, a set of CGA-N12 analogues were rationally designed based on the interaction networks between CGA-N12 and C. tropicalis KRE9 (CtKRE9). Seven CGA-N12 analogues with significantly improved antifungal activity against C. tropicalis were screened by reducing the docking energy of CGA-N12 and CtKRE9 and increasing the number of positive charges on CGA-N12 based on a stable three-dimensional model of CtKRE9. CGA-N12 and its analogues exhibited antifungal activity against C. tropicalis and its persist cells; they also inhibited biofilm formation and eradicated preformed biofilms. Compared with fluconazole, they displayed higher activities against the growth of persister cells and more effective preformed biofilm eradication. Among them, CGA-N12-0801, CGA-N12-0902 and CGA-N12-1002 displayed much higher activity and anti-proteinase digestion stability than CGA-N12. Specifically, CGA-N12-0801 was the optimal analogue, with a minimum inhibitory concentration of 3.46 μg/mL and a therapeutic index of 158.07. The results of electronic microscopy observations and KRE9 activity inhibition assays showed that CGA-N12 and its analogues killed C. tropicalis by disrupting the architecture of the cell wall and the integrity of the cell membrane. In conclusion, for the first time, we provide a simple and reliable method for the rational design of antimicrobial peptides and ideal candidates for treating Candida infections that not effectively eliminated by azole drugs.

THE EXPERIMENTAL DETERMINATION OF THE NUMBER OF FREEZING STAGES OF CANDIDA TROPICALIS FUNGAL CELLS FOR THEIR DESTRUCTION AND OBTAINING OF PROTEINS AND POLYSACCHARIDES

Candidiasis is a disease that occurs due to excessive growth of the Candida fungus. Several types of this pathogen are known, each of which can cause damage to various organs and systems. Recently, there have been reports of the loss of sensitivity of Candida fungi to most of antifungal drugs that have been used for more than 40 years. An alternative to antifungal drugs for candidiasis can be the use of a vaccine for the prevention and treatment of candidal infection. In our opinion, it is promising to use a candidal vaccine based on a subunit vaccine that contains fragments of a microorganism without ballast substances. Cell fragments of Candida fungi that have antigenic properties include proteins and polysaccharides. To isolate antigenic substances from Candida fungal cells, we chose freezing as the method of destruction. The aim of this work was to experimentally substantiate the number of freezing stages for the destruction of C. tropicalis АТСС 20336 fungi cells and the subsequent production of proteins and polysaccharides. To determine the optimal number of freezing stages in the temperature range from (25 ± 2)°С to (-25 ± 2)°С, in order to destroy the cells of C. tropicalis fungi, the studies were conducted with freezing stages 3, 4, 5, and 6. Centrifugation was used to separate the excess components. Then the preliminary and sterilizing filtration was performed on membrane filters with pore diameters of 0.45 μm and 0.22 μm. The content of protein, polysaccharides and monosaccharides were determined in each case. The protein content was determined according to the State Pharmacopoeia of Ukraine (SPhU). To determine polysaccharides, a reaction with phenol and sulfuric acid was performed. Chromatographic studies of monosaccharides were conducted using paper chromatography according to the SPhU. Based on the results of the research, it was found that solutions obtained at stages 5 and 6 of freezing the biomass of C. tropicalis fungi cells at a temperature from (25 ± 2) °C to (-25 ± 2) °C contained the highest amount of proteins and polysaccharides. It is likely that with these number of stages for freezing the biomass of C. tropicalis fungi cells, active substances are released from all layers of Candida fungi cells. Thus, it can be concluded that five stages of freezing are the optimal number that ensures the maximum extraction of polysaccharides and proteins quickly and economically.

Broad-spectrum antifungal activity of Phyllanthus niruri leaves tested against Candida species

Introduction: The emergence of resistant pathogenic microorganisms against conventional antimicrobials has become a global concern. To combat new and re-emerging infectious illnesses, new antimicrobial agents with different chemical structures and novel modes of action are required. Therefore, this study evaluated ethanolic extracts of Phyllanthus niruri for their antimicrobial activities against Candida species isolated from different clinical samples. Materials and Methods: This involved the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method for the identification of Candida species. The ethanolic extraction of P. niruri leaves was examined. The agar well diffusion method was used to determine the antifungal activity of the leaf extracts against standard American Type Culture Collection strains as well as clinical isolates of Candida species. Results: Using PCR-RFLP, Candida tropicalis was found to be the most prevalent species of Candida, followed by Candida albicans, Candida glabrata, Candida krusei and Candida parapsilosis. The ethanol extract of P. nirui leaves showed good activity against all the clinical and standard strains of Candida which were comparable to the standard drug fluconazole. The activity of P. niruri against C. albicans was highest followed by C. parapsilosis, C. tropicalis, C. glabrata and C. krusei at a concentration of 100 mg/ml. Conclusion: The findings of this study support the use of P. niruri plant to treat Candida infections, particularly fluconazole-resistant Candida species.

Amphiphilic hyperbranched polyglycerol nanoarchitectures for Amphotericin B delivery in Candida infections.

Although Amphotericin B (AMB) is considered the most effective anti-mycotic agent for treating Candida infections, its clinical use is limited due to its high toxicity. To address this issue, we developed cholesterol-based dendritic micelles of hyperbranched polyglycerol (HPG), including cholesterol-cored HPG (Chol-HPG) and cholesterol end-capped HPG (HPG@Chol), for AMB delivery. The findings suggested that the presence of cholesterol moieties could control AMB loading and release properties. Dendritic micelles inhibited AMB hemolysis and cytotoxicity in HEK 293 and RAW 264.7 cell lines while increasing antifungal activity against C. albicans biofilm formation. Furthermore, significantly lower levels of renal and liver toxicity biomarkers compared to Fungizone® ensured AMB-incorporated dendritic micelle biosafety, which was confirmed by histopathological evaluations. Overall, the Chol-HPG and HPG@Chol dendritic micelles may be a viable alternative to commercially available AMB formulations as well as an effective delivery system for other poorly soluble antifungal agents.

Antifungal Activity of Select Essential Oils against Candida auris and Their Interactions with Antifungal Drugs.

Candida auris is an emerging fungal pathogen that commonly causes nosocomial blood infections in the immunocompromised. Several factors make this pathogen a global threat, including its misidentification as closely related species, its ability to survive for weeks on fomites, and its resistance to commonly prescribed antifungal drugs, sometimes to all three classes of systemic antifungal drugs. These factors demonstrate a need for the development of novel therapeutic approaches to combat this pathogen. In the present study, the antifungal activities of 21 essential oils were tested against C. auris. Several essential oils were observed to inhibit the growth and kill C. auris, Candida lusitaniae, and Saccharomyces cerevisiae when in direct contact and at concentrations considered safe for topical use. The most effective essential oils were those extracted from lemongrass, clove bud, and cinnamon bark. These essential oils also elicited antifungal activity in gaseous form. The efficacies of formulations comprised of these three essential oils in combination with fluconazole, amphotericin B, flucytosine, and micafungin were explored. While synergism was neither observed with cinnamon bark oil nor any of the antifungal drugs, lemongrass oil displayed synergistic, additive, and indifferent interactions with select drugs. Formulations of clove bud oil with amphotericin B resulted in antagonistic interactions but displayed synergistic interactions with fluconazole and flucytosine. These essential oils and their combinations with antifungal drugs may provide useful options for surface disinfection, skin sanitization, and possibly even the treatment of Candida infections.

Postantifungal Effect of Antifungal Drugs against Candida: What Do We Know and How Can We Apply This Knowledge in the Clinical Setting?

The study of the pharmacological properties of an antifungal agent integrates the drug pharmacokinetics, the fungal growth inhibition, the fungicidal effect and the postantifungal activity, laying the basis to guide optimal dosing regimen selection. The current manuscript reviews concepts regarding the postantifungal effect (PAFE) of the main classes of drugs used to treat Candida infections or candidiasis. The existence of PAFE and its magnitude are highly dependent on both the fungal species and the class of the antifungal agent. Therefore, the aim of this article was to compile the information described in the literature concerning the PAFE of polyenes, azoles and echinocandins against the Candida species of medical interest. In addition, the mechanisms involved in these phenomena, methods of study, and finally, the clinical applicability of these studies relating to the design of dosing regimens were reviewed and discussed. Additionally, different factors that could determine the variability in the PAFE were described. Most PAFE studies were conducted in vitro, and a scarcity of PAFE studies in animal models was observed. It can be stated that the echinocandins cause the most prolonged PAFE, followed by polyenes and azoles. In the case of the triazoles, it is worth noting the inconsistency found between in vitro and in vivo studies.

A New Variant of Mutational and Polymorphic Signatures in the ERG11 Gene of Fluconazole-Resistant Candida albicans.

BackgroundResistance to antifungal drugs for treating Candida infections remains a major concern globally despite the range of medications available. Most of these drugs target key proteins essential to the life cycle of the organism. An enzyme essential for fungal cell membrane integrity, lanosterol 14–α demethylase (CYP51), is encoded by the ERG11 gene in Candida species. This enzyme is the target of azole–based drugs. The organism has, however, devised molecular adaptations to evade the activity of these drugs.Materials and MethodsClassical methods were employed to characterize clinical isolates sampled from women and dogs of reproductive age. For fluconazole efficacy studies, CLSI guidelines on drug susceptibility testing were used. To understand the susceptibility pattern, various molecular and structural analytic approaches, including sequencing, in silico site-directed mutagenesis, and protein-ligand profiling, were applied to the ERG11 gene and CYP51 protein sequences. Several platforms, comprising Clustal Omega, Pymol plugin manager, Pymol molecular visualizer, Chimera–curated Dynameomics rotamer library, protein–ligand interaction profiler, Charmm36 force field, GROMACS, Geneious, and Mega7, were employed for this analysis.ResultsThe following Candida species distribution was obtained: 37.84% C. albicans, 8.12% C. glabrata, 10.81% C. krusei, 5.41% C. tropicalis, and 37.84% of other unidentified Candida species. Two codons in the nucleotide sequence of the wild-type (CTC and CCA) coding for LEU–370 and PRO–375, respectively, were mutated to L370S and P375H in the resistant strain. The mutation stabilized the protein at the expense of the heme moiety. We found that the susceptible isolate from dogs (Can–iso–029/dog) is closely related to the most resistant isolate from humans.ConclusionTaken together, our results showed new mutations in the heme-binding pocket of caCYP51 that explain the resistance to fluconazole exhibited by the Candida isolates. So far, the L370S and P375H resistance-linked mutations have not been previously reported.

Antifungal activity of Rhopalurus crassicauda venom against Candida spp.

Fungal infections are becoming a serious problem of human diseases, being one of the most important fungal pathogens the yeast of the genus Candida. So far, fungal infection treatment faces different challenges, including the limited number of therapeutic drugs. Scorpions are known to be a valuable source of biologically active molecules, especially of peptide-derived molecules with a variety of biological effects and useful, lead compounds for drugs development. Here, we pioneer described the antifungal effect of venom, mucus, and the major toxin (Rc1) from Rhopalurus crassicauda scorpion. These results support the potential for Rc1 to be further investigated as a novel antifungal therapeutic to treat Candida infections.

Inhibitory Potential of Artificial Saliva Containing Vanillin against Biofilm Formation of Candida

Saliva plays a crucial role in oral health. Reduced salivary flow (hyposalivation) and xerostomia (dry mouth) are commonly found in many groups of patients, such as cancer patients with head and neck radiotherapy, patients taking medications with antisialogogic effects, diabetic patients, autoimmune patients, and the elderly. When salivary function is diminished, there is more risk of patients to develop opportunistic infections. One of therapeutic methods to restore lost or improve existing functions of natural saliva is the use of saliva substitutes. Several types of salivary substitutes have been developed to simulate human saliva as well as having antimicrobial property. Vanillin, an extensive flavor and aromatic component used worldwide, has been revealed to have antimicrobial potential against many types of bacteria yeasts and molds. The objective of this study was to evaluate the antimicrobial potential of vanillin-incorporated artificial saliva against biofilm formation of Candida. Artificial saliva containing different concentrations of vanillin (8, 4, 2, 1, 0.5 and 0.25 mg/mL) was prepared. Candida albicans ATCC 10231 and a clinical strain isolated from oral lesion of patient were used in this study. The Candida biofilm formation assay was performed on a 96-well plate by adding 150 μl 107colony forming unit (CFU)/ml of each Candida suspension and 50 μl of artificial saliva and incubated at 37°C in shaking incubator for 24 h. The vital Candida in biofilm formed on the bottom surface of microwell was determined by WST-8 microbial viability assay kit (Dojindo, USA). Artificial saliva without vanillin was used as a control. All tests were done in triplicate and repeated three times. Kruskal-Wallis and Dunn’ tests were used as statistical analysis. It was found that in the presence of vanillin (at concentrations > 0.5 mg/mL) the amount of vital biofilm formation of both strains of C. albicans was significantly reduced (31-56%) compared with a control. The suppressive activity was not different between both strains of Candida. Similarly, dose dependent effects were found except at 2 mg/mL and 1 mg/mL. The result was conformed to the previous study of our group that the incorporation of vanillin to surgical obturator resin could reduce the Candida biofilm formation to nearly 46-54%. The mechanisms of antifungal property of vanillin had been demonstrated to be the induction of oxidative stress, and an interference of metabolic pathways. In conclusion, artificial saliva containing vanillin exhibited a distinct inhibitory effect on biofilm formation of C. albicans as demonstrated in the present study. Attention is required for further studies to implement vanillin added artificial saliva to be used as a productive saliva substitute for the prevention or treatment of Candida infection.