Inoculation Of Candida Albicans Research Articles

α-galactosylceramide-stimulated invariant natural killer T-cells play a protective role in murine vulvovaginal candidiasis by Candida albicans.

Vulvovaginal candidiasis is a common superficial candidiasis; however, a host's immunological mechanism against vaginal Candida infection remains unknown. In this study, we aimed to elucidate the effect of iNKT cell activation on vulvovaginal candidiasis. Using a vulvovaginal candidiasis model with estrogenized mice, we evaluated the fungal burden and number of leukocyte infiltrations in the vaginal lavage of wild-type C57BL/6J mice after Candida albicans inoculation. One day before C. albicans inoculation, α-galactosylceramide (the α-GalCer group) or sterile phosphate-buffered saline (the sham group) was intraperitoneally injected into the mice. We also evaluated the level of antimicrobial peptide S100A8 in the vaginal lavage and analyzed the correlation between S100A8 concentration and the number of vaginal leukocyte infiltrations. Moreover, the number of uterine and vaginal immune cells were evaluated using flow cytometry. The number of vaginal leukocyte infiltrations was significantly higher in the α-GalCer group than in the sham group 3 days after C. albicans inoculation. In addition, the fungal burden was significantly lower in the α-GalCer group than the sham group at 7 days after inoculation. In the analysis of S100A8 concentration of vaginal lavage, there were no significant differences between these two groups, although S100A8 concentration and the number of vaginal leukocyte infiltrations were positively correlated in the α-GalCer group. Moreover, the number of vaginal iNKT cells, NK cells and CD8+ T-cells was significantly higher in the α-GalCer group 3 days after inoculation. α-GalCer-stimulated iNKT cells likely play a protective role against vulvovaginal candidiasis.

Biodistribution of free and encapsulated 99mTc-fluconazole in an infection model induced by Candida albicans

BackgroundCandida spp is an etiologic agent of fungal infections in hospitals and resistance to treatment with antifungals has been extensively reported. Thus, it is very important to develop formulations that increase effectiveness with low toxicity. In this sense, nanocarriers have been investigated, once they modify drug biodistribution profile. Thus, this study aimed to evaluate the biodistribution of free and encapsulated 99mTc-fluconazole into nanocapsules (NCs) in an experimental immunosuppressed murine model of Candida albicans infection. MethodsFluconazole was radiolabeled with technetium-99 metastable (99mTc) and encapsulated into conventional (99mTc-Fluconazole-PLA-POLOX) and surface-modified (99mTc-Fluconazole-PLA-PEG) NCs by the interfacial deposition of the preformed biodegradable polymer [poly (D,L-lactic acid) (PLA) and PLA–PEG (polyethyleneglycol)] followed by solvent evaporation. The size distribution and zeta potential of the NCs preparations were determined in a Zetasizer by photon correlation spectroscopy and laser Doppler anemometry, respectively. Free and encapsulated 99mTc-fluconazole were administered intravenously in immunosuppressed mice bearing a local infection induced by Candida Albicans inoculation in the right thigh muscle. At pre-established time intervals, tissues and organs of interest were removed and radioactivity was measured in an automatic gamma radiation counter. ResultsThe NCs diameter was between 200 and 400 nm with negative zeta potential values. Free 99mTc-fluconazole was more rapidly eliminated by the renal system compared to the encapsulated drug in NCs, which remained longer in blood circulation. The uptake of conventional NCs by mononuclear phagocyte system organs was higher than the one demonstrated by the surface-modified NCs. Both NCs remained longer in the infectious focus when compared to free 99mTc-fluconazole, but the results did not show a significant difference between NC formulations. ConclusionThese data indicate that these NCs might represent a therapeutic alternative for the treatment of candidiasis, once they remain more time in the infectious focus, allowing high retention of 99mTc-fluconazole at this site.

Experimental vaginal candidiasis: Assessment of Origanum vulgare for its treatment

The aim of this work was evaluate action of oregano (Origanum vulgare) essential oil in treatment of experimental vaginal candidiasis. A batch of 50 Wistar rats was randomly allocated into four experimental groups corresponding to treatments: T1, 1.5% oil; T2, 3% oil; T3, Nystatin and T4, control treatment (emulsion). Oil concentrations were emulsified in agar suspension at 0.8%. Vulvovaginal candidiasis was established in ovariectomized and estrus-induced rats by intravaginal inoculation of Candida albicans (106 cells-ml). Experimental rats were treated intravaginally daily for a period of 30 days and tested for clinical and hematological parameters, agent retro isolation and macroscopic alterations. Rats from T4 (Negative) treatments did exhibit major alterations exhibited in clinical parameters major alterations. Macroscopic lesions were evident in animals T1 and T4, e.g. erythema, white spots and vaginal mucosa ulcerations; two rats from T4 and one from T1 showed an enhanced uterine volume. Colony counts (UFCs) at the end of experimental period were of 3.1, 2 and 6.5 log2 for T1, T2 and T4, respectively. T3 showed the lowest UFC value of 0.5 log. Experimental results, considered as preliminary, showed a good performance for 3% O. vulgare essential oil formulation on the control of experimental vaginal candidiasis. Key words: Vaginal candidiasis, essential oil, Origanum.

Effects of fluconazole on viable cell count in experimental intraperitoneal Candida abscesses.

We investigated the effects of fluconazole in experimental intraperitoneal Candida abscesses in neutropenic mice treated with cyclophosphamide to assess a clinically appropriate method for the application of fluconazole in fungal infections in patients with neutropenia. The efficacy of fluconazole in fungal infection was investigated in treatments started immediately after Candida albicans inoculation and before C. albicans inoculation (preventive use of fluconazole). In this intraabdominal fungal abscess model, it was confirmed that fungi in already formed abscess were not reduced in number by fluconazole, even when those fungi were susceptible to fluconazole. Fluconazole was effective with both administration methods. We conclude from this study that the effect of the preventive use of fluconazole was equivalent to the effect when treatment was started immediately after fungal inoculation.

Early inflammatory responses to Candida albicans infection in inbred and complement-deficient mice

Inflammatory responses that developed in the footpad during the first 48 h after inoculation of Candida albicans were compared in six genetically defined inbred strains of mice. Tissue responses consisted predominantly of accumulations of polymorphonuclear leucocytes, the magnitude of which was significantly less in mice lacking the fifth component of complement (C5). Despite this, there was no difference between C5-sufficient and C5-deficient mice in the total infectious burden, nor did depletion of complement by treatment with cobra venom factor cause any detectable reduction in the numbers of inflammatory cells in the area of the lesion. Ablation of granulocytes had no significant effect on the fungal burden over the period of the experiment. Immunisation provided some protection against tissue damage, but did not reduce the number of yeasts at the site of infection.

Efficacy of prophylactic and early fluconazole treatment on systemic candidiasis in experimentally neutropenic rabbits.

The efficacy of prophylactic and early fluconazole treatment on experimental systemic candidiasis was investigated in neuropenic rabbits. Fifteen rabbits were used and divided into three groups: fluconazole was started 24 h before the inoculation of Candida albicans in the first group, and 24 h after the inoculation in the second group. The third group was the control group without antifungal therapy. Prophylactic and early fluconazole treatment for 7 days after C. albicans inoculation did not reduce the mortality and tissue culture positivity in the rabbits significantly. Four of the five rabbits survived 7 days both in the prophylactic and early treatment groups. However, only one rabbit survived for 7 days in the control group. In diagnostic procedures, histopathological examination and evaluation with periodic acid-Schiff stain was found to be the most sensitive. In this study, prophylactic and early fluconazole treatment were found to be insufficient for treatment of systemic candidiasis in neutropenic rabbits.

Rat palatal histology related to denture-like appliances

Two designs of palatal denture-like appliance were fitted to rats. Tooth- and tissue-borne appliances caused changes in epithelial thickness and keratin thickness, but these varied with anatomical site and type of appliance. A single inoculation of Candida al bicans at the time of insertion of the appliance failed to establish infection consistently. Debris accumulation under the appliances was a problem which will restrict long-term studies with this model.

EVALUATION OF AMPHOTERICIN B—CYCLOSPORINE INTERACTION IN THE RAT

Although a significant interaction between cyclosporine and amphotericin-B (AmpB) has been observed clinically, these findings have not been duplicated in animal studies. A total of 64 male albino rats were used in single- and multiple-dose experiments with AmpB and CsA in the absence or presence of systemic Candida infection. No significant differences in glomerular filtration rate were found in rats given single i.v. doses of AmpB 1 mg/kg compared with AmpB and CsA. Furthermore, rats given i.p. AmpB 1 mg/kg and CsA 10 mg/kg daily for 10 days showed no significant differences in GFR compared with animals given CsA alone. Morphology and CsA whole-blood pharmacokinetics were not different between groups administered single-dose CsA, AmpB, or the combination; similarities also existed with multiple-dose studies. In an attempt to mimic the clinical setting, 2 groups of rats were administered i.p. CsA 10 mg/kg/day for 10 days followed by inoculation of Candida albicans. After 48 hr, a single i.v. dose of AmpB 1.0 mg/kg was associated with a 33% decline in GFR compared with those given sterile water (P less than 0.05). Systemic clearance of CsA was markedly reduced in candidiasis rats administered AmpB compared with controls given sterile water. A significant reduction in renal Candida colony-forming units was found in rats given CsA and AmpB compared with those administered CsA alone. These data suggest that the presence of systemic Candida highlights the interaction of CsA and AmpB in the rat model.

Experimental candidiasis associated with liver injury. Role of transferrin.

In an attempt to perform a further investigation on the proposal that an increasing susceptibility to Candida infection in liver injury may be related to unsaturated transferrin level (UIBC) and/or to a total amount of transferrin represented by TIBC, we conducted experimental candidiasis using mice with galactosamine-induced liver injury and investigated the effect of preadministration of transferrin prior to inoculation of Candida albicans. Final mortality was 10% in the mice without liver injury and without transferrin (Group 1) and ones with liver injury and with transferrin (Group 3). By contrast a 50% mortality was given in one only with liver injury (Group 2). The TIBCs in Groups 1 and 3 were significantly higher than that in Group 2. The UIBCs in Groups 2 and 3, although there was no significant difference between them, were significantly lower than that in Group 1. This study confirmed that transferrin (TIBC) may have a direct deterring effect on systemic Candida infection and the decreased TIBC in the liver injury enhances the growth of C. albicans.

The effect of Candida albicans on the permeability of rat palatal epithelium: an ultrastructural and biochemical study.

The effect of a palatal acrylic appliance and/or infection with Candida albicans on the permeability of rat palatal epithelium has been investigated. Although normal rats, or rats inoculated with Candida albicans but without a prosthesis, had a barrier to perfused lanthanum, some low-molecular-weight proteins were able to pass through the epithelium. When infection was established by inoculation of Candida albicans under an acrylic plate, the epithelium became permeable to perfused lanthanum. Polyacrylamide gel electrophoresis of perfusates showed that a selective permeability to proteins was retained in such animals. Removal of acrylic plates from infected animals resulted in healing and restoration of the barrier to lanthanum.

Topical Ketoconazole for Experimental Candida Keratitis in Rabbits

Topical ketoconazole (2% ointment three times per day for three weeks) markedly reduced the severity of keratitis produced with Candida albicans inoculation in the right eyes of 20 rabbits. Clinical scores of affected eyes were significantly lower in the treated eyes than in the controls, which consisted of the 20 inoculated but untreated left eyes of the same rabbits. All cultures of corneal scrapings from the treated eyes were negative on the 12th day after inoculation, while two cultures were still positive at the end of the experiment (day 21) in the control eyes. Histopathologic examination showed less severe inflammatory changes in the treated eyes than in the control eyes.

Experimental and clinical studies of 5-fluorocytosine activity in candida ocular infections, II. The effect of 5-fluorocytosine in treating experimental candida infection in rabbits' eyes.

Mild and severe experimental ocular infections in rabbits' eyes were induced by inoculation of Candida albicans with or without addition of dexamycin drops. These rabbits were treated with 5-Fluorocytosine, topically, orally and in a combined topical and oral manner. The topical treatment was effective only in mild infections. Severe infections responded to oral and especially to combined oral-tropical treatment.