Farnesol modulation of Rhodotorula mucilaginosa in biofilm and planktonic forms.

Biofilms are important to the virulence of human pathogenic fungi, and some molecules have been found to play key roles in the growth and regulation of fungal biofilms. Farnesol, one of these molecules, is well-described for some microorganisms but is still scarcely known for Rhodotorula spp. This study aimed to evaluate the influence of farnesol on the biofilm of R. mucilaginosa. Initially, screening with 0.2 mM to 2.1 mM of farnesol was evaluated against planktonic forms. A concentration of this compound was then chosen and evaluated for its effect on biofilm in formation and on preformed biofilm after 24, 48 and 72 hours. The impact of farnesol was evaluated by colony-forming units (CFU) counts, determination of metabolic activity and quantification of total biomass. In the presence of 0.9 mM, farnesol was able to decrease the CFU number, at 48 hours, when the biofilm was in formation, although it did not affect the preformed biofilms. Thus, our results show that farnesol exerts a modulating activity during biofilm formation for R. mucilaginosa, with this compound reducing the metabolic activity and total biomass of the biofilms.

Promising effect of propolis and a by-product on planktonic cells and biofilm formation by the main agents of human fungal infections.

Few antifungals available today are effective in treating biofilms. Thus, it is urgent to discover new compounds, such as natural products, that provide improvements to existing treatments or the development of new antifungal therapies. This study aimed to perform a comparative analysis between the green propolis extract (PE) and its by-product, a waste of propolis extract (WPE) through a screening with Candida sp., Fusarium sp. and Trichophyton sp. The antifungal property of PE and WPE was assessed by the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) determination in planktonic cells. The influence of both extracts on the inhibition of biofilm formation in these fungi was also tested. The WPE MIC and MFC values (68.75 to 275.0 µg/mL) were three to twelve times lower than the values obtained for PE (214.06 to 1712.5 µg/mL). PE was more efficient than WPE in inhibiting the biofilm initial phase, especially in C. albicans. Meanwhile, WPE had dose-dependent behavior for the three fungi, being more effective on filamentous ones. Both PE and WPE showed excellent antifungal activity on planktonic cells and demonstrated great efficacy for inhibiting biofilm formation in the three fungi evaluated.

Control of Cryptococcus Gattii Biofilms by an Ethanolic Extract of Cochlospermum Regium (Schrank) Pilger Leaves.

Cryptococcus gattii is an etiologic agent of cryptococcosis and a serious disease that affects immunocompromised and immunocompetent patients worldwide. The therapeutic arsenal used to treat cryptococcosis is limited to a few antifungal agents, and the ability of C. gattii to form biofilms may hinder treatment and decrease its susceptibility to antifungal agents. The objective of this study was to evaluate the antifungal and antibiofilm activities of an ethanolic extract of Cochlospermum regium (Schrank) Pilger leaves against C. gattii. The antifungal activity was assessed by measuring the minimum inhibitory concentration (MIC) using the broth microdilution technique and interaction of the extract with fluconazole was performed of checkerboard assay. The antibiofilm activity of the extract was evaluated in 96-well polystyrene microplates, and the biofilms were quantified by counting colony forming units. The extract showed antifungal activity at concentrations of 62.5 to 250 µg/mL and when the extract was evaluated in combination with fluconazole, C. gattii was inhibited at sub-MIC levels. The antibiofilm activity of the extract against C. gattii was observed both during biofilm formation and on an already established biofilm. The results showed that the ethanolic extract of the leaves of C. regium shows promise for the development of antifungal drugs to treat cryptococcosis and to combat C. gattii biofilms.

Influence of Eugenia uniflora Extract on Adhesion to Human Buccal Epithelial Cells, Biofilm Formation, and Cell Surface Hydrophobicity of Candida spp. from the Oral Cavity of Kidney Transplant Recipients.

This study evaluated the influence of the extract of Eugenia uniflora in adhesion to human buccal epithelial cells (HBEC) biofilm formation and cell surface hydrophobicity (CSH) of Candida spp. isolated from the oral cavity of kidney transplant patients. To evaluate virulence attributes in vitro, nine yeasts were grown in the presence and absence of 1000 µg/mL of the extract. Adhesion was quantified using the number of Candida cells adhered to 150 HBEC determined by optical microscope. Biofilm formation was evaluated using two methodologies: XTT (2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) and crystal violet assay, and further analyzed by electronic scan microscopy. CSH was quantified with the microbial adhesion to hydrocarbons test. We could detect that the extract of E. uniflora was able to reduce adhesion to HBEC and CSH for both Candida albicans and non-Candida albicansCandida species. We also observed a statistically significant reduced ability to form biofilms in biofilm-producing strains using both methods of quantification. However, two highly biofilm-producing strains of Candida tropicalis had a very large reduction in biofilm formation. This study reinforces the idea that besides growth inhibition, E. uniflora may interfere with the expression of some virulence factors of Candida spp. and may be possibly applied in the future as a novel antifungal agent.

Cellular Structural Changes in Candida albicans Caused by the Hydroalcoholic Extract from Sapindus saponaria L.

Vulvovaginal candidiasis (VVC) is a disease caused by the abnormal growth of yeast-like fungi in the mucosa of the female genital tract. Candida albicans is the principal etiological agent involved in VVC, but reports have shown an increase in the prevalence of Candida non-C. albicans (CNCA) cases, which complicates VVC treatment because CNCA does not respond well to antifungal therapy. Our group has reported the in vitro antifungal activity of extracts from Sapindus saponaria L. The present study used scanning electron microscopy and transmission electron microscopy to further evaluate the antifungal activity of hydroalcoholic extract from S. saponaria (HE) against yeast obtained from VVC and structural changes induced by HE. We observed the antifungal activity of HE against 125 vaginal yeasts that belonged to four different species of the Candida genus and S. cerevisae. The results suggest that saponins that are present in HE act on the cell wall or membrane of yeast at the first moments after contact, causing damage to these structures and cell lysis.

Early state research on antifungal natural products.

Nosocomial infections caused by fungi have increased greatly in recent years, mainly due to the rising number of immunocompromised patients. However, the available antifungal therapeutic arsenal is limited, and the development of new drugs has been slow. Therefore, the search for alternative drugs with low resistance rates and fewer side effects remains a major challenge. Plants produce a variety of medicinal components that can inhibit pathogen growth. Studies of plant species have been conducted to evaluate the characteristics of natural drug products, including their sustainability, affordability, and antimicrobial activity. A considerable number of studies of medicinal plants and alternative compounds, such as secondary metabolites, phenolic compounds, essential oils and extracts, have been performed. Thus, this review discusses the history of the antifungal arsenal, surveys natural products with potential antifungal activity, discusses strategies to develop derivatives of natural products, and presents perspectives on the development of novel antifungal drug candidates.

Colonization of the oral cavity by yeasts in patients with chronic renal failure undergoing hemodialysis.

OBJECTIVES: To determine the frequency of yeast in the oral cavity of patients with chronic renal failure, undergoing hemodialysis (PCRFH); identification and antifungal susceptibility profile of yeast and demographic profile of patients. METHODS: We performed mouthwash in 146 PCRFH; the rinse fluid was collected and cultured, yeasts grown were identified by phenotypic and molecular methods. The antifungal susceptibility profile was determined against nystatin, amphotericin B, fluconazole, voriconazole, and caspofungin based in Clinical and Laboratory Standards Institute (document M27-A3). RESULTS: Positive culture was observed in 39% of patients, of whom 53% were women; the median of dialysis time was 2.9 years. The age of the colonized patients varied between 26 and 84 years, with a median of 52.5 years. PCRFH over 45 years were significantly more colonized (P = 0.0108) as well as denture wearers (84.0%). We isolated 81 yeasts, predominantly Candida albicans (63%) followed by Candida glabrata. In general, yeasts were sensitive to the evaluated antifungal agents, but there was significant variation in the minimum inhibitory concentration, especially among non-C. albicans Candida (NCAC) compared to fluconazole, caspofungin, and amphotericin B. NCAC required significantly higher concentrations of fluconazole (P < 0.01). CONCLUSION: The rate of colonization by yeasts in PCRFH was high, and there was variability in species distribution and antifungal susceptibility profile. These results are little known in this group of patients and are important for controlling the risk of developing invasive fungal infections.

Spermicidal and anti-Trichomonas vaginalis activity of Brazilian Sapindus saponaria.

BACKGROUND: Sapindus saponaria is used traditionally for curing ulcers, external wounds and inflammations. The spermicidal and anti-Trichomonas activity of S. saponaria and its effect on Lactobacillus acidophilus were evaluated. METHODS: Water-ethanol (WE) and butanolic (BE) extracts, as well as a purified sample of saponins (SP) from S. saponaria were tested for spermicidal and anti-Trichomonas activity and for their effect on L. acidophilus. RESULTS: WE, BE and SP immobilized spermatozoa at a minimum effective concentration (MEC) of 2.5 (gram %) for extracts and 1.25 (gram %) for SP. The effective concentrations that caused 50% immobilization of spermatozoa (EC50) were 0.5 (gram %) for WE and SP, and 0.1 (gram %) for BE. The compounds were effective against Trichomonas vaginalis (Minimum Inhibitory Concentration = 0.156 mg/mL for WE and BE, and 0.078 mg/mL for SP against a clinical strain (CS); and 0.312, 0.156 and 0.078 mg/mL for WE, BE and SP, respectively, against an ATCC strain). In all concentrations tested, the growth of L. acidophilus was not reduced. CONCLUSION: The in vitro study proved the spermicidal and anti-Trichomonas activity of S. saponaria. Complementary in vivo studies should be made for establish the use as a vaginal spermicide, particularly in Brazil and Latin America.

In vitro antifungal activity of curcumin mediated by photodynamic therapy on Sporothrix brasiliensis.

BACKGROUND: Sporothrix brasiliensis is a pathogenic dimorphic fungus that affects humans and animals causing sporotrichosis. The treatment of this disease with conventional antifungals commonly results in therapeutic failures and resistance. Therefore, this study aimed to evaluate the in vitro effect of curcumin (CUR) mediated by photodynamic therapy (PDT) in its pure state and incorporated into pharmaceutical formulation in gel form, on the filamentous and yeast forms of S. brasiliensis. METHODS: Cells from both forms of the fungus were treated with pure curcumin (PDT-CUR). For this, CUR concentrations ranging from 0.09 to 50 µM were incubated for 15 min and then irradiated with blue LED at 15 J/cm². Similarly, it was performed with PDT-CUR-gel, at lower concentration with fungistatic action. After, a qualitative and quantitative (colony forming units (CFU)) analysis of the results was performed. Additionally, reactive oxygen species (ROS) were detected by flow cytometry. Results PDT with 0.78 µM of CUR caused a significant reduction (p < 0.05) in cells of the filamentous and yeast form, 1.38 log10 and 1.18 log10, respectively, in comparison with the control. From the concentration of 1.56 µM of CUR, there was a total reduction in the number of CFU (≥ 3 log10). The PDT-CUR-gel, in relation to its base without CUR, presented a significant reduction (p < 0.05) of 0.83 log10 for the filamentous form and for the yeast form, 0.72 log10. ROS release was detected after the PDT-CUR assay, showing that this may be an important pathway of death caused by photoinactivation. Conclusion PDT-CUR has an important in vitro antifungal action against S. brasiliensis strains in both morphologies.

Cell wall associated proteins involved in filamentation with impact on the virulence of Candida albicans.

Candida albicans is a commensal microorganism of the human microbiota that can be associated with superficial to disseminated infections. This species possesses several attributes that contribute to pathogenesis and virulence, such as the ability to transition from yeast to hyphae forms. During this transition, several changes occur in the fungal cell wall, which is the first point of contact between the pathogen and the host. The cell wall is a bi-layered structure, containing chitin, glucan, and proteins, the latter of which play important roles in pathogenesis. Given the importance of this structure, particularly in filamentation, this review focuses on the studies of C. albicans mutants for genes that encode cell wall-associated proteins that have an important role in the virulence, and also have a role in hyphal morphogenesis. Thus, we highlight some proteins whose mutation is associated with attenuated virulence in vivo and have defective filamentation. We also provide examples of proteins whose inactivation does not impair the filamentation yet are still important for C. albicans virulence.

The zoonosis sporotrichosis can be successfully treated by photodynamic therapy: A scoping review.

Sporotrichosis is a worldwide zoonosis, prevalent in tropical and subtropical regions. In recent years, there has been a substantial increase in human and feline cases reported in Brazil. Despite this, the antifungal treatment for sporotrichosis is still limited, and thus, research into new therapeutic modalities must be encouraged. Recently, photodynamic therapy has been introduced as a treatment for sporotrichosis. This work presents an overview of both in vitro and in vivo studies that have used photodynamic therapy in the context of photoinactivation of Sporothrix species. Until now, as far as the authors are aware, this is the first scope review specifically on photodynamic therapy for the treatment of sporotrichosis. A systematic electronic search was conducted in two databases: Web of Science and PubMed. Seven original articles published from 2010 to July 2021 were selected, six of which met the proposed inclusion and exclusion criteria and were considered in this scoping review. Concerning the photoinactivation of Sporothrix spp. the results have been promising as studies, in both animals and humans, have reported significant clinical and mycological effects. The most used photosensitizers were methylene blue and its derivatives, and aminolevulinic acid and its methyl derivative, methyl aminolevulinic acid. In conclusion, photodynamic therapy has great potential in treatment of sporotrichosis, as its fungicidal effect both in vitro and in vivo has clearly been demonstrated. Photodynamic therapy could be used in conjunction with classic antifungal agents to optimize treatment outcomes.

New approach to the use of propolis against dermatomycosis.

In recent years, propolis extract (PE) has demonstrated antimicrobial and anti-inflammatory properties. The aim of this study was to evaluate the antifungal activity of a bioadhesive thermoresponsive system containing 16% propolis (BTSP 16%) against Microsporum canis, Nannizzia gypsea, Trichophyton mentagrophytes and T. rubrum. We also evaluated PE alone against the same strains. The results showed that both PE and BTSP 16% significantly reduced the fungal viability of all evaluated strains. In addition, they interacted with the biofilm of these species in different stages of biofilm formation. We observed that the bioadhesive and thermoresponsive properties of BTSP 16% prolonged propolis presence at infection sites, leading to positive results against planktonic fungal cells and mature biofilms. These characteristics make this formulation a valuable alternative treatment for dermatomycosis.

In vivo activity of Sapindus saponaria against azole-susceptible and -resistant human vaginal Candida species.

BACKGROUND: Study of in vivo antifungal activity of the hydroalcoholic extract (HE) and n-BuOH extract (BUTE) of Sapindus saponaria against azole-susceptible and -resistant human vaginal Candida spp. METHODS: The in vitro antifungal activity of HE, BUTE, fluconazole (FLU), and itraconazole (ITRA) was determined by the broth microdilution method. We obtained values of minimal inhibitory concentration (MIC) and minimum fungicide concentration (MFC) for 46 strains of C. albicans and 10 of C. glabrata isolated from patients with vulvovaginal candidiasis (VVC). VVC was induced in hyperestrogenic Wistar rats with azole-susceptible C. albicans (SCA), azole-resistant C. albicans (RCA), and azole-resistant C. glabrata (RCG). The rats were treated intravaginally with 0.1 mL of HE or BUTE at concentrations of 1%, 2.5% and 5%; 100 µg/mL of FLU (treatment positive control); or distilled water (negative control) at 1, 24, and 48 h after induction of the infection, and the progress of VVC was monitored by culturing and scanning electron microscopy (SEM). The toxicity was evaluated in cervical cells of the HeLa cell line. RESULTS: The extracts showed in vitro inhibitory and fungicidal activity against all the isolates, and the MIC and MFC values for the C. glabrata isolates were slightly higher. In vivo, the SCA, RCA, and RCG infections were eliminated by 21 days post-infection, with up to 5% HE and BUTE, comparable to the activity of FLU. No cytotoxic action was observed for either extract. CONCLUSIONS: Our results demonstrated that HE and BUTE from S. saponaria show inhibitory and fungicidal activity in vitro, in addition to in vivo activity against azole-resistant vaginal isolates of C. glabrata and azole-susceptible and resistant isolates of C. albicans. Also considering the lack of cytotoxicity and the low concentrations of the extracts necessary to eliminate the infection in vivo, HE and BUTE show promise for continued studies with purified antifungal substances in VVC yeast isolates.

High colonization by Candida parapsilosis sensu stricto on hands and surfaces in an adult intensive care unit.

BACKGROUND: Yeasts of the Candida parapsilosis complex have frequently been reported as agents of fungal infection in Brazil and worldwide, most of the cases are related to hospital-acquired infection. C. parapsilosis is the third most common cause of candidemia, and the hands of hospital workers as well as hospital surfaces have been suggested as possible sources. OBJECTIVES: In this study we verified the frequency of C. parapsilosis on the hands of workers and on surfaces in the adult intensive care unit (AICU) of a tertiary hospital in Paraná-Brazil. METHODS: Surface samples were collected with swabs moistened with saline, and a plastic bag with distilled water was used to collect samples from hands. The yeasts were identified by morphology, MALDI-TOF mass spectrometry and PCR-RFLP of the secondary alcohol dehydrogenase-encoding gene (SADH) after digestion with the restriction enzyme BanI. RESULTS AND CONCLUSIONS: A total of 223 yeast were found, of which 101 (45.29%) were identified as C. parapsilosis sensu stricto. Of these, 46.66% (n=35) were found on surfaces and 44.59% (n=66) on the hands of the employees. The analysis of C. parapsilosis strains by microsatellite loci (CP1, CP4, CP6 and B5) showed 80 different genotypes. Their antifungal susceptibility profile, evaluated by the microdilution broth method, revealed that C. parapsilosis was sensitive to amphotericin B, fluconazole and voriconazole, but not to micafungin. The results revealed the heterogeneity of the yeast population, suggesting that there is no common source of contamination in the AICU of this hospital.

First Study of Naturally Formed Fungal Biofilms on the Surface of Intragastric Balloons.

BACKGROUND: Intragastric balloon (IGB) is a medical device used in the endoscopic treatment of pre-obesity and obesity. The involvement of IGB with biofilms has been previously reported; however, little is still known. We determine the frequency of biofilms naturally formed on the external surface of IGB, as well as some variables related to IGB types and patients features, species of fungi involved, and biofilm evidence. METHODS: A retrospective study was conducted based on endoscopies and medical records of patients with explanted IGB between 2015 and 2018, which had masses strongly adhered to the surface of the balloon, suspecting the presence of a biofilm. From 2018, the samples of those masses were investigated seeking biofilm characterization based on mycological and structural aspects. RESULTS: A total of 149 endoscopies were surveyed; 27 IGBs (18.12%) showed signs suggesting biofilm formation. There was no significant difference between biofilm involvement in IGB and the anthropometric and demographic profile of the patients. On the other hand, there was a significant difference regarding the IGB type, 24.05% of the adjustable IGB were compromised by biofilm, while in non-adjustable IGB, it was 11.43% (p = 0.04; OR 2.45; 95% CI, 0.98-6.12). Candida glabrata was the most isolated fungal species from the well-organized fungal biofilm. CONCLUSIONS: The frequency of fungal biofilm naturally formed on the external surface of IGB was elevated. The risk of biofilm formation was increased for the adjustable IGB, but it did not relate to the demographic data and anthropometric patient profile.

Hypericin-P123-photodynamic therapy in an ex vivo model as an alternative treatment approach for onychomycosis caused by Fusarium spp.

BackgroundFusarium has been considered an opportunistic pathogen, causing several infections in humans, including onychomycosis. In addition, a high resistance to conventional antifungals has been linked to this genus. Photodynamic Therapy (PDT), known as a non-invasive therapy, can be an alternative treatment for fungal infections, based on the excitation of a photosensitizing compound (PS) by a specific length of light, causing damage to the target. The aim of this study was to evaluate the effects of a formulation of Hypericin (Hyp) encapsulated in Pluronic™ (P123), via photodynamic therapy (PDT), on planktonic cells and biofilms in Fusarium spp. using in vitro and ex vivo assays. Materials & Methods epidemiology studies about Fusarium spp. in onychomycosis was perfomed, carried out molecular identification, compared the antifungal activity of the conventional antifungals with PDT with encapsulated Hypericin (Hyp-P123), carried out detection of reactive oxygen species, and measured the antibiofilm effect of the Hyp-P123-PDT in vitro and in an ex vivo model of onychomycosis. Results Hyp-P123-PDT exhibited a fungicidal effect in vitro with reductions ≥ 3 log10. ROS generation increased post-Hyp-P123-PDT in Fusarium spp. Hyp-P123-PDT showed a potent inhibitory effect on adhesion-phase and mature biofilms in vitro tests and an ex vivo model of onychomycosis (p<0.0001). Conclusion Hyp-P123-PDT had a potent effect against Fusarium spp., suggesting that photodynamic therapy with Hyp-P123 is a safe and promising treatment for onychomycosis in clinical practice.

Ultrastructural imaging of Candida albicans adhesion to rat genital epithelium through scanning and transmission electron microscopy.

The adhesion of Candida albicans to the genital epithelium has not been fully investigated in vivo. The objective of this study was to evaluate the ultrastructural aspects of C. albicans adhesion in the lower genital system of female Wistar rats through scanning and transmission electron microscopy. The genital infection persisted until the end of the experiment, and all rats showed the same adhesion aspects. Various associated yeast/hyphae were observed in the lumen and adhered both at the vaginal and endocervical levels where the fungal filamentation process occurred. In the vaginal epithelium, closely adhered yeasts were observed as stretched strands bridging between yeasts and the epithelium surface. Different stages of the adhesion, where yeasts internalized into the epithelial cell inside a cytoplasmic vacuole, resembling endocytosis, and a wide fibrillar-floccular, glycocalyx-like layer on the yeasts were observed. On the endocervix, the adhesion occurred between the cilia. In the uterine body, only a yeast-like form was observed with superficial contact. This study reached the initial goal of demonstrating an experimental model for in vivo studies. Continuation of this line of research is important for studies of vulvovaginal candidiasis.

Examination of potential virulence factors of Candida tropicalis clinical isolates from hospitalized patients.

Candida tropicalis has been reported to be one of the Candida species which is most likely to cause bloodstream and urinary tract infections in hospitalized patients. Accordingly, the aim of this study was to characterize the virulence of C. tropicalis by assessing antifungal susceptibility and comparing the expression of several virulence factors. This study was conducted with seven isolates of C. tropicalis from urine and blood cultures and from central venous catheter. C. tropicalis ATCC 750 was used as reference strain. Yeasts adhered (2 h) to epithelial cells and silicone and 24 h biofilm biomass were determined by crystal violet staining. Pseudohyphae formation ability was determined after growth in fetal bovine serum. Enzymes production (hemolysins, proteases, phospholipases) was assessed by halo formation on agar plates. Susceptibility to antifungal agents was determined by E-test. Regarding adhesion, it can be highlighted that C. tropicalis strains adhered significantly more to epithelium than to silicone. Furthermore, all C. tropicalis strains were able to form biofilms and to express total hemolytic activity. However, protease was only produced by two isolates from urine and by the isolates from catheter and blood. Moreover, only one C. tropicalis (from catheter) was phospholipase positive. All isolates were susceptible to voriconazole, fluconazole and amphotericin B. Four strains were susceptible-dose dependent to itraconazole and one clinical isolate was found to be resistant.

Propolis extract has bioactivity on the wall and cell membrane of Candida albicans.

ETHNOPHARMACOLOGICAL RELEVANCE: The use of natural products such as propolis extract (PE) is a promising alternative when topically administered to replace conventional antifungals, mostly due to its therapeutic applications, ease of access and low toxicity. However, despite being the subject of several mycology studies, they focus primarily on exploiting their antimicrobial activity, lacking information on the mechanisms of action of PE on Candida spp., characterizing its antifungal potential. AIM OF THE STUDY: To elucidate the bioactivity of PE on the cellular structure of Candida albicans. MATERIALS AND METHODS: A total of seven C. albicans clinical isolates plus a reference strain of C. albicans ATCC 90028 were used in this study. The PE was characterized and its effect on C. albicans was determined by susceptibility and growth kinetics assays; interference on C. albicans germination and filamentation; evaluation of the integrity of the C. albicans cell wall and membrane, as well as its mutagenic potential. RESULTS: The PE presented strong inhibitory activity, which showed its greatest antifungal activity at 12 h with dose and time dependent fungistatic characteristics, effectively inhibiting and interfering on C. albicans filamentation. In addition, PE caused membrane and cell wall damage with intracellular content extravasation. Moreover, PE was not mutagenic. CONCLUSIONS: The bioactivity of PE is mainly related to the loss of integrity membrane as well as the integrity of the cell wall and consequent increase in permeability, without mutagenic effects.

Effect of experimental diabetes on the development and maintenance of vulvovaginal candidiasis in female rats.

OBJECTIVE: The purpose of this study was to develop an experimental model of diabetes in female rats and verify its influence on vulvovaginal candidiasis. STUDY DESIGN: The animals were divided into control and diabetic groups. Diabetes was induced with the use of an intravenous solution of alloxan (42 mg/kg bodyweight). One week after confirmation of hyperglycemia, the inoculation of Candida albicans yeast, previously standardized from a vaginal isolate, in concentrations of about 5 x 10(8), was performed. Infection control was made through vaginal culture, Papanicolaou cytology, and scanning electron microscopy (SCEM). RESULTS: The results pointed to different glycemias between the control (74.8 +/- 2.6) and experimental groups (543.1 +/- 12.1) and a significant bodyweight decrease (227.6 +/- 4.77 and 204 +/- 6.39, respectively). The positive infection was shown by culture, Papanicolaou test, and SCEM in the experimental group. CONCLUSION: Diabetes mellitus causes hyperglycemia, which was favorable to the vaginal colonization and infection by C albicans.