Successful treatment of experimental murine vulvovaginal candidiasis with gentian violet.

Aim: This study evaluated the antifungal efficacy of gentian violet (GV) in an experimental vulvovaginal candidiasis (VVC) model. Materials & methods: In vitro susceptibility and cytotoxicity assays were performed to validate the antifungal potential and safety of GV. The antifungal efficacy was then evaluated in vivo through comparative analysis of the fungal burden following treatment with GV or nystatin, as well as assessment of the vaginal tissue by histology and electron microscopy. Results: GV demonstrated a safe antifungal profile against C. albicans, with a significant decrease in fungal burden and an improvement in the inflammatory process evaluated histologically. Conclusion: The results of this study motivate further assessment of GV as a promising alternative for VVC therapy.

Analysis of the antifungal potential of Macrocybe titans extract against Candida albicans.

Aim: To investigate the antifungal potential of Macrocybe titans extracts against Candida albicans. Material & methods: Extracts were obtained as aqueous (EfraMat-22 and EfraMat-45) and methanolic/ethyl acetate fractions. Results: Broth microdilution and disk diffusion assays showed that EfraMat-45 provided the best results in terms of minimum inhibitory concentration. Scanning electron microscopy analysis revealed morphological changes and slight damage on the surfaces of cells exposed to EfraMat-45 at the MIC. Fluorescence microscopy analysis of the yeasts showed cell elongation. EfraMat-45 presented high levels of phenolic compounds and flavonoids, high antioxidant activity and absence of in vitro cytotoxicity. Conclusion: The results indicated that the aqueous extract of M. titans is highly promising as an antifungal agent.

Polycaprolactone nanofibers colonized by HeLa cells: an alternative for in vitro investigation of fungal infection.

Introduction: In vitro 3D equivalent tissues can be used for studies of fungal infections. Objectives: To develop 3D electrospun nanofibers using polycaprolactone (PCL) colonized by HeLa cells as a possible in vitro model for the investigation of fungal infection. Materials & methods: A PCL solution was synthesized and electrospun. HeLa cells were cultured on the nanostructured PCL scaffolds, forming a 3D structure. Physicochemical, biological and Candida albicans infection assays were performed in this model. Results: The nanostructured PCL scaffolds showed favorable physicochemical characteristics and allowed the colonization of HeLa cells, which showed indications of extracellular matrix production. Conclusions: Fungal infection was evidenced in the 3D nanostructured PCL scaffolds, being viable, economical and compatible to study fungal infections in vitro.

Insight into the antifungals used to address human infection due to Trichosporon spp.: a scoping review.

Trichosporonosis infections have been increasing worldwide. Providing adequate treatment for these infections remains a challenge. This scoping review contains information about potential antifungals to treat this pathology. Using online databases, we found 76 articles published between 2010 and 2020 related to this topic. Classic antifungals, molecules and biomolecules, repositioned drugs and natural products have been tested against species of Trichosporon. Experimental research has lacked depth or was limited to in vitro and in vivo tests, so there are no promising new candidates for the clinical treatment of patients with trichosporonosis. Furthermore, most studies did not present appropriate scientific criteria for drug tests, compromising their quality.

Different expression levels of ALS and SAP genes contribute to recurrent vulvovaginal candidiasis by Candida albicans.

Aim: To study the behavior of Candida albicans in women with vulvovaginal candidiasis (VVC), recurrent VVC (RVVC) and asymptomatic (AS), regarding adhesion on HeLa cells and their ability to express secreted aspartic proteinases (SAP) genes, agglutinin-like sequence (ALS) genes and HWP1. Materials & methods: The adhesion of Candida albicans to HeLa cells was evaluated by colony-forming units, and the expressed genes were evaluated by qRT-PCR. Results: AS and VVC isolates showed greater ability to adhere HeLa cells when compared with RVVC isolate. Nevertheless, RVVC isolate exhibited upregulation of a large number of genes of ALS and SAP gene families and HWP1 gene. Conclusion: The results demonstrated that RVVC isolate expressed significantly important genes for invasion and yeast-host interactions.

Impact of serial systemic infection on Candida albicans virulence factors.

Aim: To evaluate changes in virulence and pathogenicity approaches from Candida albicans after successive passages in a murine model of systemic candidiasis. Materials & methods: Phenotypic assays were performed using colonies recovered from animals infected serially, totalizing five passages. Results: A progressive infection was observed along the passages, with increased fungal burden and the presence of greater inflammatory areas in the histopathological findings. Recovered strains exhibited increased filamentation and biofilm abilities, along with modulation of phospholipase and proteinase activities. Conclusion: Repeated contact between yeast and host increased the expression of virulence factors. Furthermore, a correspondence between phenotypic profile and proteomic data obtained previously was observed.

Vulvovaginal candidiasis in a murine model of diabetes emphasizing the invasive ability of etiological agents.

Aim: To compare the pathogenesis of vulvovaginal candidiasis by three Candida species in diabetic mice. Materials & methods: Estrogenized and diabetic mice were challenged with C. albicans, C. tropicalis and C. glabrata. Results: Diabetic animals infected with C. albicans and C. tropicalis maintained the highest fungal burden, despite of high levels of proinflammatory cytokines (IL-6 and TNF-α), respectively. For C. glabrata, the results were similar in diabetic and nondiabetic groups. Conclusion:C. tropicalis was as invasive as C. albicans, and both were more effective than C. glabrata. This ability was attributed to filamentation, which may be stimulated by glucose levels from vaginal fluid. In addition, the high burden may be attributed to the apparent immunological inefficiency of the diabetic host.

Silver nanoparticles stabilized with propolis show reduced toxicity and potential activity against fungal infections.

Aim: Elucidate the antifungal efficacy of biologically synthesized silver nanoparticles with ethanolic propolis extract (AgNPs PE) against the planktonic forms and biofilms of clinically important fungi. Materials & methods: AgNPs were synthesized, characterized and evaluated for cytotoxicity, mutagenicity and antimicrobial activity. Results: AgNPs PE displayed a colloidal appearance, good stability and size of 2.0-40.0 nm. AgNPs PE demonstrated lower cytotoxicity and nonmutagenic potential. In addition, AgNPs PE displayed antifungal properties against all tested isolates, inhibiting growth at concentrations lower than the cytotoxic effect. Mature biofilms treated for 48 h with AgNPs PE showed significant reduction of viable cells, metabolic activity and total biomass. Conclusion: This is the first time that AgNPs have been synthesized from an ethanolic extract of propolis only, proving antifungal, antibiofilm, atoxic and nonmutagenic properties.

Copolymeric micelles as efficient inert nanocarrier for hypericin in the photodynamic inactivation of Candida species.

Aim: To evaluate the efficacy of photodynamic inactivation (PDI) mediated by hypericin encapsulated in P-123 copolymeric micelles (P123-Hyp) alone and in combination with fluconazole (FLU) against planktonic cells and biofilm formation of Candida species Materials & methods: PDI was performed using P123-Hyp and an LED device with irradiance of 3.0 mW/cm2 . Results: Most of isolates (70%) were completely inhibited with concentrations up to 2.0 µmol/l of HYP and light fluence of 16.2 J/cm2. FLU-resistant strains had synergic effect with P123-HYP-PDI and FLU. The biofilm formation was inhibited in all species, in additional the changes in Candida morphology observed by scanning electron microscopy. Conclusion: P123-Hyp-PDI is a promising option to treat fungal infections and medical devices to prevent biofilm formation and fungal spread.

Fusarium oxysporum is an onychomycosis etiopathogenic agent.

AIM: To evaluate and characterize the etiopathogenesis of the fusarial onychomycosis in an ex vivo study through fragments of sterile human nail, without the addition of any nutritional source. MATERIALS & METHODS: The infection and invasion of Fusarium oxysporum in the nail were evaluated by scanning electron microscopy (SEM), CFU, matrix, histopathology and Fourier Transform Infrared Spectrometer coupled to an equipment with diamond accessory (FTIR-ATR). RESULTS: F. oxysporum infected and invaded across the nail, regardless of application face. However, the dorsal nail surface was the strongest barrier, while the ventral was more vulnerable to infection and invasion process. The fungal-nail interaction resulted in the formation of a dense biofilm. CONCLUSION: F. oxysporum infect and invade the healthy human nail, resulting in biofilm formation. Therefore, F. oxysporum is likely a primary onychomycosis agent.

γ-irradiation from radiotherapy improves the virulence potential of Candida tropicalis.

AIM: To evaluate if radiation used in radiotherapy can cause changes in the virulence potential of Candida tropicalis ATCC 750. MATERIALS & METHODS: C. tropicalis was exposed in vitro to identical dose and scheme of irradiation would be used in patients with head and neck cancer. Some virulence parameters were analyzed before and after irradiation. RESULTS: Colony morphologies were irreversibly affected by irradiation. Increase in growth rate, filamentation, adhesion on cell lines and phagocytosis process were also observed. Overall the irradiated C. tropicalis cells became more efficient at causing systemic infection in mice. CONCLUSION: γ-radiation induced important changes in C. tropicalis increasing its virulence profile, which could directly affect the relationship between yeasts and hosts.

A new small-molecule KRE2 inhibitor against invasive Candida parapsilosis infection.

AIM: To investigate the antifungal activity of MOL3, a small molecule that was selected by virtual screening, against Candida spp. MATERIALS & METHODS: The antifungal activity of MOL3 was evaluated using standard strains and clinical isolates. Activity was evaluated in both in vitro tests and animal models. RESULTS: The minimum fungicidal concentration of MOL3 against Candida spp. ranged from 16 to 128 mg/l. MOL3 at the sub-minimum fungicidal concentration inhibited hyphal elongation. The remaining yeast cells presented morphological changes and were metabolically inactive. MOL3 was toxicologically inert both in vitro and in the animal model. MOL3 also reduced experimental systemic infection by C. parapsilosis in mice. CONCLUSION: The selection of MOL3 by virtual screening was successful, revealing a promising antifungal candidate.

Propolis: a potential natural product to fight Candida species infections.

AIM: To evaluate the effect of propolis against Candida species planktonic cells and its counterpart's biofilms. MATERIALS & METHODS: The MIC values, time-kill curves and filamentation form inhibition were determined in Candida planktonic cells. The effect of propolis on Candida biofilms was assessed through quantification of CFUs. RESULTS: MIC values, ranging from 220 to 880 µg/ml, demonstrated higher efficiency on C. albicans and C. parapsilosis than on C. tropicalis cells. In addition, propolis was able to prevent Candida species biofilm's formation and eradicate their mature biofilms, coupled with a significant reduction on C. tropicalis and C. albicans filamentation. CONCLUSION: Propolis is an inhibitor of Candida virulence factors and represents an innovative alternative to fight candidiasis.

Animal models for the effective development of atrophic vaginitis therapies: possibilities and limitations.

INTRODUCTION: Vaginal atrophy (VA) is an inflammation of the vagina that develops when there is a significant decrease in levels of the estrogen. Prolonged periods of hypoestrogenism may induce severe VA and treatment is essential. This is a significant problem which requires more focused attention for the development of existing and future therapies. AREAS COVERED: This review evaluates the suitable animal models of VA, including: mice, rodents and non-human primates. It focuses particularly on the possibilities and limitations of these in vivo models for the effective development of VA therapies. EXPERT OPINION: Hormone replacement therapy (HRT) has been prescribed and successfully used for VA. However, some studies have shown that HRT may be linked to an increased risk of breast cancer, coronary heart diseases and others risks. Thus, there is a growing interest in effective and safe alternatives to VA symptoms. There are, however, a number of things that must be considered for future drug discovery efforts. One major consideration is what animal model should be used and whether the model is appropriate for the study aim. Similarly, research studies must also consider the influencing factors on these animal models, so that these models can effectively mimic the actual disease. The authors also highlight the need to standardize research parameters to produce more reliable and reproducible data.