Isolation of Candida dubliniensis in denture stomatitis

Evaluation of photodynamic therapy efficacy vs. conventional antifungal therapy in patients with poor-fitting dentures suffering from denture stomatitis. A prospective clinical study

BACKGROUND

The long-term use of antifungal therapy in denture stomatitis (DS) treatment could be accompanied by antifungal-resistant strain onset, leading to compromised therapeutic procedure and disease reappearance. Photodynamic therapy (PDT) has shown the ability to eradicate oral infections and resistance strains. This prospective clinical study aimed to assess the PDT's effectiveness compared to the conventional treatment on clinical and microbiological parameters in patients with DS without denture wear during the treatment and follow-ups.

METHODS

Forty-two patients diagnosed with DS were randomly assigned to one-session single PDT application (test group) or conventional antifungal therapy (control group). Clinical and microbiological parameters were assessed and analyzed before and at 3rd, 15th, and 30th day following the treatments. Microbiological samples were analyzed by a Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The data was statistically analyzed.

RESULTS

Prior to the treatment, Candida species, including C. albicans (100%), C. glabrata (33%), C. tropicalis (31%), C. krusei (31%) were isolated in all patients. Both treatment procedures demonstrated a statistically significant reduction in C. albicans at all follow-up time intervals (p < 0.05). However, PDT displayed a statistically significant reduction in C. krusei compared to the conventional treatment at all follow-up periods (p < 0.05). Clinical parameters improved considerably in the test group compared to the control group at the 3rd and 15th day of follow-up.

CONCLUSION

One-session single PDT application demonstrated significant improvement in both clinical and microbiological outcomes in a short-term period, resulting in complete Candida spp. eradication compared to conventional antifungal therapy.

Effect of Professional Denture Cleaning on Surface Roughness of Silicone or Acrylic Soft Relining Materials

The aim of this study was to investigate the effects of combining mechanical (ultrasonic) and chemical cleaning (using denture cleaners) on the surface roughness of silicone or acrylic soft relining materials. The silicone soft relining material with the lowest Shore A hardness and a acrylic soft relining material routinely used in Japan were selected. Four groups were established based on type of treatment: immersion in water (W); ultrasonic cleaning in tap water (U); ultrasonic cleaning in a hypochlorous acid denture cleanser (HU); or ultrasonic cleaning in an acidic denture cleanser (AU). Following the tests, surface roughness was determined as the arithmetic mean height of the surface (Sa) and maximum height (Sz). Data were analyzed using the Kruskal-Wallis test followed by Bonferroni correction for a multiple comparison. No significant difference was observed in the Sa or Sz of the silicone soft relining material between the 4 groups. Significant differences were observed in the Sa of the acrylic soft relining material between Groups W and HU (p=0.008) and between Groups W and AU (p=0.008), but no significant differences in the Sz among the 4 groups. Combining U with AU or U with HU yielded no increase in the surface roughness of the silicon soft relining material. The surface roughness of the acrylic soft relining material showed an increase, however, with the combination treatments used.

Risk factors and immunological biomarkers in denture stomatitis: An observational cross-sectional study

OBJECTIVE

Assess risk factors, local and systemic immunological biomarkers in healthy individuals and with Denture Stomatitis (DS).

DESIGN

For this observational transversal study, 27 participants without DS (Group 0), 24 with moderate DS (Group 1), and 25 with severe DS (Group 2) were assessed for sociodemographic, behavioral, and clinical parameters, microbial load of Candida spp., Staphylococcus spp., Streptococcus mutans, Pseudomonas spp., and enterobacteria, and cytokine and C-reactive protein levels. ANOVA, Fisher's exact, Kruskal-Wallis, Mann-Whitney, Wilcoxon and Pearson's chi-square tests were used for data analysis (α = 0.05).

RESULTS

Group 1 had a significantly higher mean age compared to the other groups (P = 0.018), but no correlation was identified between age and DS (P = 0.830; r = 0.025). No significant differences were found among the groups for other sociodemographic and behavioral characteristics. Group 1 had significantly older upper and lower dentures; however, no correlation was identified between age of upper (P = 0.522; r = 0.075) and lower (P = 0.143; r = 0.195) dentures and DS. The microbial load of Candida albicans on the dentures (P = 0.035) and Candida spp. on the palate (P = 0.008) of the groups 1 and 2 was higher than group 0. Group 1 and 2 had higher Candida spp. counts on denture (P = 0.003) than group 0. There was no difference among groups for bacterial analyzed. Group 1 showed higher and Group 2 intermediate salivary levels of IL-6 compared to Group 0. There was no difference in the C-reactive protein levels among groups.

CONCLUSIONS

Microbial load of Candida spp. is the factor with the strongest relationship with DS, with capacity for local signaling through IL-6.

Functional Characterization of a Bacillus-Derived Novel Broad-Spectrum Antifungal Lipopeptide Variant against Candida tropicalis and Candida auris and Unravelling Its Mode of Action

Limited treatment options, recalcitrance, and resistance to existing therapeutics encourage the discovery of novel antifungal leads for alternative therapeutics. Antifungal lipopeptides have emerged as potential candidates for developing new and alternative antifungal therapies. In our previous studies, we isolated and identified the lipopeptide variant AF4 and purified it to homogeneity via chromatography from the cell-free supernatant of Bacillus subtilis. AF4 was found to have broad-spectrum antifungal activity against more than 110 fungal isolates. In this study, we found that clinical isolates of Candida tropicalis and Candida auris exposed to AF4 exhibited low MICs of 4 to 8 mg/L. Time-kill assays indicated the in vitro pharmacodynamic potential of AF4. Biocompatibility assays demonstrated ~75% cell viability at 8 mg/L of AF4, indicating the lipopeptide's minimally cytotoxic nature. In lipopeptide-treated C. tropicalis and C. auris cells, scanning electron microscopy revealed damage to the cell surface, while confocal microscopy with acridine orange(AO)/propidium iodide (PI) and FUN-1 indicated permeabilization of the cell membrane, and DNA damage upon DAPI (4',6-diamidino-2-phenylindole) staining. These observations were corroborated using flow cytometry (FC) in which propidium iodide, 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA), and rhodamine 123 (Rh123) staining of cells treated with AF4 revealed loss of membrane integrity, increased reactive oxygen species (ROS) production, and mitochondrial membrane dysfunction, respectively. Membrane perturbation was also observed in the 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence study and the interaction with ergosterol was observed by an ergosterol binding assay. Decreased membrane dipole potential also indicated the probable binding of lipopeptide to the cell membrane. Collectively, these findings describe the mode of action of AF4 against fungal isolates by membrane disruption and ROS generation, demonstrating its antifungal potency. IMPORTANCE C. tropicalis is a major concern for candidiasis in India and C. auris has emerged as a resistant yeast causing difficult-to-treat infections. Currently, amphotericin B (AMB) and 5-flucytosine (5-FC) are the main therapeutics for systemic fungal infections; however, the nephrotoxicity of AMB and resistance to 5-FC is a serious concern. Antifungal lead molecules with low adverse effects are the need of the hour. In this study, we briefly describe the antifungal potential of the AF4 lipopeptide and its mode of action using microscopy, flow cytometry, and fluorescence-based assays. Our investigation reveals the basic mode of action of the investigated lipopeptide. This lipopeptide with broad-spectrum antifungal potency is apparently membrane-active, and there is a smaller chance that organisms exposed to such a compound will develop drug resistance. It could potentially act as a lead molecule for the development of an alternative antifungal agent to combat candidiasis.

Efficacy of curcumin in the treatment of denture stomatitis: A randomized double-blind study

Background

The prevalence of denture stomatitis has been shown to vary from 15% to 65% in complete denture wearers. In recent years, a number of studies across the globe have investigated the various biological effects of curcumin, curcumin, a polyphenolic compound derived from dietary spice turmeric, possesses diverse pharmacologic effects including anti-inflammatory, antioxidant, antiproliferative and antiangiogenic activities. The aim of this study was to evaluate the efficacy of curcumin local application with common antifungal agent clotrimazole for the treatment of denture stomatitis.

Materials and Methods

A randomised double-blind clinical trial with approval of institutional ethical committee consisting fifty participants divided into two groups (17 men-33 women) with the clinical signs and symptoms of oral candidiasis. The diagnosis was supported by microbiological cultures. Group A patients were prescribed the clotrimazole and Group B patients were prescribed the curcumin ointment which was dispensed in similar amber coloured bottles. Data were analyzed using Chi-squared tests, Wilcoxon's signed rank sum test and Mann-Whitney test.

Results

The mean candidal colony counts before treatment in Groups A and Group B were 63.960 and 37.080, respectively. The mean candida colony counts after treatment in both the groups were 14.080 and 3.720, respectively. There was a statistically significant difference between the two groups when mean candida colony counts were calculated before and after treatment. However, intergroup comparison between the two groups considering the mycological eradication showed that there was no statistically significant difference with P = 0.404.

Conclusion

Topical application of curcumin as a natural ingredient could be an effective agent for the treatment of denture stomatitis as an alternative to regular clotrimazole therapy.

Nanocarriers of Miconazole or Fluconazole: Effects on Three-Species Candida Biofilms and Cytotoxic Effects In Vitro

The contribution of different Candida species in oral fungal infections has stimulated the search for more effective therapies. This study assessed the antibiofilm effects of nanocarriers of miconazole (MCZ) or fluconazole (FLZ) on Candida biofilms, and their cytotoxic effects on murine fibroblasts. Three-species biofilms (Candida albicans/Candida glabrata/Candida tropicalis) were formed on 96-well plates, and they were treated with nanocarriers (iron oxide nanoparticles coated with chitosan—“IONPs-CS”) of MCZ or FLZ at 39/78/156 µg/mL; antifungals alone at 156 µg/mL and artificial saliva were tested as positive and negative controls, respectively. Biofilms were analyzed by colony forming units (CFU), biomass, metabolic activity, and structure/viability. The cytotoxicity (L929 cells) of all treatments was determined via 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) reduction assay. Data were submitted to one- or two-way ANOVA, followed by Tukey’s or Fisher LSD’s tests (p < 0.05). IONPs-CS-MCZ at 78 µg/mL promoted similar antibiofilm and cytotoxic effects compared with MCZ at 156 µg/mL. In turn, IONPs-CS-FLZ at 156 µg/mL was overall the most effective FLZ antibiofilm treatment, surpassing the effects of FLZ alone; this nanocarrier was also less cytotoxic compared with FLZ alone. It can be concluded that both nanocarriers are more effective alternatives to fight Candida biofilms compared with their respective positive controls in vitro, being a promising alternative for the treatment of oral fungal infections.

Oral prosthetic microbiology: aspects related to the oral microbiome, surface properties, and strategies for controlling biofilms

The oral cavity is an environment that allows for the development of complex ecosystems; the placement of prosthetic devices as a consequence of partial or total tooth loss may alter the diversity of microbial communities. Biofilms on the surface of materials used in dental prostheses can promote important changes in the mechanic and aesthetic properties of the material itself and may cause local and systemic diseases for the prosthetic wearer. This review presents the main features of the oral microbiome associated with complete or partial dentures and dental implants. The main diseases associated with microbial colonization of prosthetic surfaces, factors that may affect biofilm formation on prosthetic materials, as well as novel alternative therapies aiming to reduce biofilm formation and/or to eradicate biofilms formed on these materials are also explored.

Does microwave and hydrogen peroxide disinfection reduce Candida albicans biofilm on polymethyl methacrylate denture surfaces?

STATEMENT OF PROBLEM

Whether the disinfection of polymethyl methacrylate (PMMA) dentures eliminates Candida albicans biofilm is unclear.

PURPOSE

The purpose of this in vitro study was to determine the antimicrobial effect of immersion in hydrogen peroxide (H₂O₂) and subsequent application of microwaves on the formation of C albicans biofilm on the surface of polished and unpolished PMMA disks.

MATERIAL AND METHODS

Polished and unpolished PMMA disks (n=40) were mounted in a Center for Disease Control (CDC) biofilm reactor by adding yeast-dextrose-peptone (YPD) broth inoculated with C albicans in a cell suspension for 24 hours. After this period, the PMMA disks (n=8) were disinfected with 5 different solutions: saline solution, 1% sodium hypochlorite (NaOCl), H₂O₂, H₂O₂ microwaved at 650 W for 3 minutes (H₂O₂/μw), and distilled water microwaved at 650 W for 3 minutes (H₂O/μw). On the polished and unpolished surface of each disk, arbitrary fluorescence units (AFU) were quantified with the live/dead bacterial viability kit (Invitrogen) by using confocal laser scanning microscopy (CLSM) to evaluate 10 different areas of each surface; these were counted as the colony-forming units (CFUs). The mean values were compared by using the Mann-Whitney U test (α=.05).

RESULTS

Polished surfaces disinfected with H₂O₂/μw obtained the lowest viable cells (9.76 AFU) and nonviable cells (12.46 AFU) compared with H₂O/μw and H₂O_2. In the unpolished surface the lowest mean values of viable cells (14.64 AFU) and nonviable cells (12.46 AFU) were obtained for the PMMA disks disinfected with H₂O/μw compared with H₂O₂/μw and H₂O₂. Both polished and unpolished disks showed significant difference (P<.05) compared with the group of PMMA disks immersed in saline solution. No CFUs were detected in the polished or unpolished PMMA disks immersed in H₂O₂/μw or in NaOCl.

CONCLUSIONS

H₂O₂ alone did not eliminate the formation of the biofilm of C albicans; however, in combination with the use of the microwave at 650 W for 3 minutes, the biofilm formation of C albicans on polished surfaces was reduced. The number of AFUs of viable-nonviable cells and CFUs depended on whether the surfaces are polished or unpolished.

Evaluating the role of local host factors in the candidal colonization of oral cavity: A review update

Human oral cavity is home to a number of organisms, Candida albicans being one of them. This review article aims at understanding the correlation between the oral candidal colonization and the local host factors that may influence it with special emphasis on congenital craniofacial anomalies such as cleft lip and palate (CLP). Various scientific databases were searched online and relevant articles were selected based on the inclusion criteria. A comparative study was done to understand the interdependence of various factors (including CLP) and oral candidal colonization. The results revealed a strong association of certain local host factors which may influence the oral colonization of Candida species. Factors such as mucosal barrier, salivary constituents and quantity of saliva, congenital deformities like CLP, oral prostheses such as dentures/palatal obturators and fixed orthodontic appliances (FOAs) were identified. All these factors may directly affect the growth of Candida in the oral cavity. Although numerous studies have pointed a positive correlation between Oral Candidal colonization and local host factors such as oral prostheses, FOA, and oral mucosal barrier only one study has been done, in the Indian subcontinent with respect to the correlation of candidal colonization and CLP. After the evaluation of all the factors mentioned in various case studies, it can be concluded that the presence of local host factors such as orofacial clefts, dental prostheses, FOA, xerostomia, and atrophy of the oral mucous membrane lead to significant increase in candidal colonization, but since very few studies in regard to CLP have been done worldwide and in India, in particular, further studies are warranted.

Comparison of adhesiveness of chewing gum to hard and soft denture base materials

PURPOSE

The purpose of this study was to compare the adhesiveness of chewing gum to hard and soft denture base materials to investigate food retention associated with the basal surface of the denture.

METHODS

Test specimens were fabricated using acrylic resin[Re], cobalt-chromium alloy[Co], zirconia[Zr], silicone soft relining material[SS], and acrylic soft relining material[AS]. Samples were set on a top-and-bottom pair lifting platform equipped with a digital force gauge. The experimenter chewed 3.0 g of chewing gum for 5 min. After surface saliva was wiped off, the chewing gum was placed on the lower test fragment and compressed until the distance between the upper and lower test fragments decreased to 1 mm. The upper test fragment was pulled at a crosshead speed of 100 mm/min. Adhesiveness was measured under dry conditions, and under wet conditions with inter-positioned artificial saliva.

RESULTS

Under dry conditions, the adhesive strength was 17.04 ± 1.99 N for Re, 12.88 ± 2.20 N for Co, 3.80 ± 1.03 N for Zr, 5.76 ± 1.41 N for SS, and 12.54 ± 2.44 N for AS. Under wet conditions, the adhesive strength was 5.26 ± 1.64 N for Re, 0.96 ± 0.21 N for Co, 3.32 ± 0.40 N for Zr, 5.20 ± 1.35 N for SS, and 6.78 ± 1.97 N for AS.

CONCLUSIONS

Among the hard denture base materials, zirconia recorded low adhesiveness and Re recorded high adhesiveness under both wet and dry conditions. The adhesiveness of Co was low under wet conditions but high under dry conditions. Among the soft denture base materials, SS under dry conditions recorded lower adhesiveness than that of AS. The adhesiveness of SS was low under both wet and dry conditions.

Effect of mechanical and chemical cleaning on surface roughness of silicone soft relining material

PURPOSE

This study aims to investigate the effect of mechanical and chemical cleaning on the surface roughness of silicone soft relining materials.

METHODS

We selected silicone soft relining materials with the highest (Soft) and lowest (Supersoft) Shore A hardness. In the abrasion test, specimens were cleaned 50,000 times using a kitchen sponge (Sponge), a soft (Soft brush) or hard (Hard brush) denture brush, or stored in water (No cleaning). In the immersion test, specimens were immersed in either water (Water), neutral peroxide denture cleanser (Neutral), alkaline peroxide denture cleanser (Alkaline), or hypochlorite denture cleanser (Hypochlorite) for 1440 h. Surface roughness of the arithmetic mean height of the surface (Sa) and maximum height (Sz) were measured before and after the tests. Data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests.

RESULTS

In the abrasion test, significant differences were observed for Sa and Sz with Soft relining materials, but not for No cleaning and Sponge. In the immersion test, significant differences were observed for Sa and Sz with Soft relining materials, but not between Water and Neutral or Water and Alkaline. Significant differences were observed with Supersoft, except between Water and Neutral or Water and Alkaline for Sa and between Water and Neutral for Sz.

CONCLUSIONS

Mechanical cleaning using a sponge did not increase the surface roughness of the material with a high Shore A hardness. Furthermore, neutral peroxide denture cleanser did not increase the roughness of materials with high and low Shore A hardness.

Properties of silver contained coatings on CoCr alloys prepared by vacuum plasma spraying

The silver contained coatings on cast Cobalt Chrome (CoCr) alloys were prepared by vacuum plasma spraying technique. The Scanning Electron Microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray Diffraction (XRD), energy dispersive spectrometry (EDS), properties of corrosion resistance, wear resistance and effect of vitro antibacterial on the surface of silver contained coating were investigated. The cytotoxicity of the coatings was performed with L-929 fibroblasts by MTT assay. SEM showed that the surfaces of the coatings were dense, smooth, no obvious cracks except only a few pores. XRD analysis indicated that the contents of the surface were mainly Ag and Cr except a small amount of Ag₂O, Cr₂O₃. EDS analysis indicated that the distributions of Cr and Ag were uniform without any large-scale clustering. The wear resistance of silver coatings is similar to that of CoCr alloys, and the corrosion resistance is slightly better than that of CoCr alloys. The Ag coating had no significant effect on the proliferation of L929 cells. The antibacterial results indicated that the number of S. mutans and C. albicans were significantly reduced on the surface of silver contained coating than that of CoCr alloys. All the results indicated that the silver contained coatings can be achieved by vacuum plasma spraying technique with good surface characteristic and antibacterial properties and have promising applications in biomedical area.

Efficacy of photodynamic therapy versus local nystatin in the treatment of denture stomatitis: A randomized clinical study

AIM

The aim of the present randomized clinical study was to compare the efficacies of photodynamic inactivation (PDI) to nystatin (NST) in terms of prevalence of Candida species in cases with denture stomatitis (DS).

METHODS

Thirty-six patients were randomly divided into two groups; 18 in PDI and 18 in NST. Irradiation was carried out by using the GaA1As diode laser with wavelength, mode of transmission, laser output and energy density were standardized at 660 nm, continuous mode, 100 mW power and 28 J/cm2 respectively. The PDI was applied twice a week, with an interval of at least 48 h among the sessions during four weeks. Topical nystatin oral suspension 100,000 IU was used four times daily for 15 days. The existence of Candida spp. was confirmed by employing the microbiological culture technique. Candida colony counts from the palates and dentures surfaces, quantified as colony forming unit (CFU)/mL, measured at baseline, at the end of treatments (day 15), and at follow-up (days 30 and 60) and the prevalence of Candida spp. were identified in the two groups of treatments.

RESULTS

The overall CFU/mL values were higher in the dentures of the patients of both the groups than those from the palates. During all time periods of the study, the CFU/mL values obtained from both NST and PDI groups showed no significant differences. For dentures and palates, a significant reduction in mean CFU/mL values was observed on day 15 compared with baseline (day 0) in both NST and PDI groups. It can be seen that the effect size of treatments was large for the palates of patients in the NST group (1.79) and moderate for the palates of patients in the PDI group (0.63). On the other hand, the effect size was very large for the dentures for both groups (NST group = 3.01; PDI group = 1.58). C. albicans was the most common species on both dentures and palates of patients throughout the study period followed by C. tropicalis and C. glabrata.

CONCLUSION

Out of all the Candida spp., C. albicans showed the highest prevalence among all species. In addition, PDI was equally effective as nystatin for the treatment of DS.

Therapeutic tools for oral candidiasis: Current and new antifungal drugs

BACKGROUND

Candidiasis is one of the most common opportunistic oral infections that presents different acute and chronic clinical presentations with diverse diagnostic and therapeutic approaches. The present study carries out a bibliographic review on the therapeutic tools available against oral candidiasis and their usefulness in each clinical situation.

MATERIAL AND METHODS

Recent studies on treatment of oral candidiasis were retrieved from PubMed and Cochrane Library.

RESULTS

Nystatin and miconazole are the most commonly used topical antifungal drugs. Both antifungal drugs are very effective but need a long time of use to eradicate the infection. The pharmacological presentations of miconazole are more comfortable for patients but this drug may interact with other drugs and this fact should be assessed before use. Other topical alternatives for oral candidiasis, such as amphotericin B or clotrimazole, are not available in many countries. Oral fluconazole is effective in treating oral candidiasis that does not respond to topical treatment. Other systemic treatment alternatives, oral or intravenous, less used are itraconazole, voriconazole or posaconazole. Available novelties include echinocandins (anidulafungin, caspofungin) and isavuconazole. Echinocandins can only be used intravenously. Isavuconazole is available for oral and intravenous use. Other hopeful alternatives are new drugs, such as ibrexafungerp, or the use of antibodies, cytokines and antimicrobial peptides.

CONCLUSIONS

Nystatin, miconazole, and fluconazole are very effective for treating oral candidiasis. There are systemic alternatives for treating recalcitrant infections, such as the new triazoles, echinocandins, or lipidic presentations of amphotericin B.

Candida sp. Infections in Patients with Diabetes Mellitus

Candidiasis has increased substantially worldwide over recent decades and is a significant cause of morbidity and mortality, especially among critically ill patients. Diabetes mellitus (DM) is a metabolic disorder that predisposes individuals to fungal infections, including those related to Candida sp., due to a immunosuppressive effect on the patient. This review aims to discuss the latest studies regarding the occurrence of candidiasis on DM patients and the pathophysiology and etiology associated with these co-morbidities. A comprehensive review of the literature was undertaken. PubMed, Scopus, Elsevier’s ScienceDirect, and Springer’s SpringerLink databases were searched using well-defined search terms. Predefined inclusion and exclusion criteria were applied to classify relevant manuscripts. Results of the review show that DM patients have an increased susceptibility to Candida sp. infections which aggravates in the cases of uncontrolled hyperglycemia. The conclusion is that, for these patients, the hospitalization periods have increased and are commonly associated with the prolonged use of indwelling medical devices, which also increase the costs associated with disease management.

Efficacy of Camellia sinensis extract against Candida species in patients with denture stomatitis

Background and Purpose:

Denture stomatitis is a chronic inflammation disease of the oral mucosa, which is specified by erythematous lesions mainly in the upper palate. Nystatin as a polyene, a class of antifungal agents, is one of the effective drugs to treat denture stomatitis. Considering the expansion of utilizing herbal drugs to cure many kinds of diseases, the present study was conducted to investigate the effects of Camellia sinensis (green tea), which has the most chemical and influence similarity with nystatin, against denture stomatitis.

Materials and Methods:

This study was conducted on 22 patients with a positive mycological evidence for denture stomatitis caused by Candida species. The study population was divided into two groups, namely green tea and nystatin, receiving green tea mouthwash 0.5% and nystatin suspension 100,000 U/ml, respectively. The lesion size and number of yeast colonies were measured before and after the treatment.

Results:

According to the results, both groups showed reduced lesion size, clinical improvement, and significant reduction of Candida colony count in both group of patients were showedafter the therapeutic. Based on the results of polymerase chain reaction, Candida albicans was the most common species isolated from denture stomatitis. There was no significant difference between the two study groups in terms of Candida species distribution (P=0.700).

Conclusion:

Green tea demonstrated a comparable anti-Candida activity with regard to nystatin; therefore, it could be recommended as an alternative treatment.

Cytokine gene polymorphism in denture stomatitis patients: A clinical study

OBJECTIVE

This clinical study investigated the association between cytokine gene polymorphism and Candida growth in denture stomatitis (DS) patients.

SUBJECTS AND METHODS

Saliva and blood samples of 160 complete denture wearers (80 healthy controls and 80 with DS) were collected for mycological and gene polymorphism testing, respectively. Salivary Candida growth and TNF-α, TGF-β, IL-6, and IL-10 genotypes were investigated. Data were analyzed using Student's t test, Mann-Whitney U test, chi-square analysis, and continuity (yates) correction tests (p < .05).

RESULTS

Candida albicans colony counts in saliva were significantly higher in the DS group and in the TNF-α GG genotype (p < .05). TGF-β TC GG and TGF-β CC GG haplotypes were significantly higher in DS and control groups, respectively (p < .05). C. albicans colony counts were significantly higher in control group in the TGF-β TC GG haplotype (p < .05). Candida glabrata colony counts were significantly higher in the DS group than the control group in IL-6 GG genotype (p < .05). The difference between DS types in IL-6 genotypes was significant with lower expression level in DS type 3 than DS type 1 and also type 2 (p ≤ .01).

CONCLUSION

The significant differences in some genotypes of the TNF-α, TGF-β, and IL-6 in DS patients are promising in understanding the host defense in DS.

In Vitro Antifungal Susceptibility of Candida Species Isolated from Iranian Patients with Denture Stomatitis

Background

Candida-associated denture stomatitis (CADS) is a common fungal infection in people who wear dentures. The main objective of this study was to make molecular identification of causative agents of CADS and in vitro antifungal susceptibility testing (AFST) in the Iranian patients with denture stomatitis.

Methods

A total of 134 Candida spp. were obtained from patients with denture stomatitis. The Candida spp. were identified using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) involving the universal internal transcribed spacer (ITS1 and ITS4) primers, which were subjected to digestion with MspI and BlnI restriction enzymes. The in vitro antifungal susceptibility of Candida spp. to fluconazole (FLC), terbinafine (TRB), itraconazole (ITC), voriconazole (VRC), posaconazole (POS), ketoconazole (KET), amphotericin B (AMB), and caspofungin (CAS) was evaluated using the Clinical and Laboratory Standards Institute M27-A3 and M27-S4 guidelines.

Results

Overall, C. albicans was the most commonly isolated species (n = 84; 62.6%), followed by C. glabrata (n = 23; 17.2%), C. tropicalis (n = 16; 12%), and C. parapsilosis (n = 11; 8.2%). Posaconazole had the lowest geometric mean minimum inhibitory concentration (MIC) (0.03 μg/ml), followed by AMB (0.05 μg/ml), ITC (0.08 μg/ml), VRC (0.11 μg/ml), CAS (0.12 μg/ml), KET (0.15 μg/ml), and FLC (0.26 μg/ml).

Discussion

Our study showed that C. albicans was most prevalent in Iranian patients with CADS and was susceptible to both azoles and amphotericin B. In addition, POS could be an appropriate alternative to the current antifungal agents used for the treatment of CADS, as well as in the treatment of recurrent candidiasis.

Photodynamic inactivation of Candida ssp. on denture stomatitis. A clinical trial involving palatal mucosa and prosthesis disinfection

Denture stomatitis (DS) is the most common oral fungal infection in denture wearers. Photodynamic inactivation (PDI) has been showing to be an effective technique in vivo against fungi, including fungal infections in the oral cavity. The disinfection of both oral mucosa and denture may represent a real advantage in terms of fungus control. This clinical study was designed to explore methylene blue (MB)-mediated PDI on oral mucosa and prosthesis of patients with DS. Subjects with DS were divided into two groups. One group received treatment based on the use of oral miconazole gel 2% (MIC). The other group received treatment by PDI using MB at 450 μg/mL and a diode laser (λ = 660 nm) with 100 mW and fluence of 28 J/cm². Clinical outcome was evaluated regarding the degree of oral mucosa erythema and microbiological reduction of Candida spp. located in both palatal mucosa and prosthesis. Our results showed that PDI was significantly more effective than MIC in ameliorating inflammation after 15 days. Following 30 days, no statistically significant differences were observed between groups. Regarding the fungal burden, although the MIC group has presented more pronounced inactivation than PDI for both mucosa and prosthesis, no statistically significant differences were detected between them. This clinical study suggests that PDI can reduce fungal load and decrease the inflammation degree in patients with Candida-associated denture stomatitis.

Curcumin-mediated anti-microbial photodynamic therapy against Candida dubliniensis biofilms

The purpose of this study was to evaluate the effectiveness of anti-microbial photodynamic therapy (aPDT) mediated by curcumin (Cur) associated with LED light against biofilms of Candida dubliniensis, and further, investigate cellular uptake and drug penetration through the biofilms under confocal laser scanning microscopy (CLSM). Four C. dubliniensis strains were tested: three clinical isolates from HIV-positive patients and one reference strain (CBS 7987). Biofilms were treated with three Cur concentrations (20.0, 30.0, and 40.0 μM). All samples were incubated in the dark for 20 min and exposed to a 5.28 J/cm² of LED light fluence. Additional samples of each strain were treated either with Cur or LED light only. Control samples had neither Cur nor light. After aPDT, results were read using the XTT salt reduction method. The data were statistically analyzed by two-way ANOVA followed by Games-Howell post-hoc test (α = 0.05). Confocal laser scanning microscopy was used to verify both the uptake of Cur by yeast cells and its penetration through the biofilm. The results showed that aPDT promoted significant reduction on the metabolism of the biofilm-organized cells of C. dubliniensis. Further, while Cur was rapidly taken up by C. dubliniensis cells, a longer time interval was required to allow Cur penetration into biofilm cells. Based on these results, aPDT associating LED and Cur presents promising potential on fungal control of biofilms of C. dubliniensis.

Oral mycobiome in community-dwelling elderly and its relation to oral and general health conditions

OBJECTIVE

Oral fungal infection is generally associated with dysbiosis related to antibiotic use, immunodeficiency, or frailty. However, fungal colonization in a typical population without apparent symptoms and its associated conditions are poorly understood. In this study, oral fungal colonization in community-dwelling and independently living elderly populations was evaluated and factors affecting fungal colonization were analyzed.

SUBJECTS AND METHODS

The subjects (410; 181 males and 229 females) were 75-99 years of age; those under prior antibiotic use were excluded. Fungal populations in the saliva were evaluated by PCR-based molecular techniques. Body mass index (BMI), smoking habits, and oral health conditions were examined.

RESULTS

Salivary fungal amounts exceeded 10⁴  CFU/ml in 63 (15.4%) of 410 subjects. Candida albicans was most frequently detected (98.4%), followed by Candida glabrata (54.0%), and Candida dubliniensis (38.1%) in those subjects with fungi at 10⁴  CFU/ml or over. Fungi at 10⁴  CFU/ml or over in the presence of C. glabrata or C. dubliniensis was significantly associated with low BMI.

CONCLUSIONS

Candida albicans, C. glabrata, and C. dubliniensis dominated the oral mycobiome in Japanese community-dwelling elderly. Lower BMI might signify compromised health status and thus could result in susceptibility to specific candidiasis by C. glabrata and C. dubliniensis.

Identificação das espécies de Candida em portadores de estomatite protética e avaliação da susceptibilidade ao miconazol e à terapia fotodinâmica

INTRODUÇÃO: Próteses mucossuportadas são consideradas facilitadoras, em potencial, da estomatite protética (EP), condição caracterizada pelo aspecto eritematoso, difuso ou pontilhado da mucosa palatina sob a base das próteses. A etiologia da doença é multifatorial, embora a infecção por Candida seja uma causa bastante comum. OBJETIVO: Relacionar a EP com a presença de Candida, identificar as espécies de Candida mais prevalentes, a partir do meio CHROMagar Candida(r), e caracterizar o perfil de sensibilidade das colônias ao miconazol e à terapia fotodinâmica (TFD). MATERIAL E MÉTODO: A amostra foi constituída por 45 usuários de prótese total, sendo 30 com diagnóstico clínico de EP e 15 sem a doença. Realizou-se raspagem com swab da mucosa palatina e das próteses, e as amostras foram semeadas em CHROMagar Candida(r), para identificação de espécies de C. albicans, C. krusei e C. tropicalis. Após incubação e leitura das placas, as colônias foram reisoladas em Ágar Sabouraud, para caracterização da sensibilidade ao miconazol e à TFD. RESULTADO: Espécies de Candida estiveram presentes em 53,33% das amostras dos pacientes com EP e em 6,67% das amostras dos pacientes sem EP, considerando-se o total de amostras de mucosa (p=0,008) e próteses (p=0,001). As espécies mais prevalentes foram C. albicans (36,67% e 53,33%), seguida de C. tropicalis (13,33% e 16,67%) e C. krusei (13,33% e 6,67%), em mucosa e prótese, respectivamente. As amostras mostraram maior sensibilidade ao miconazol que à TFD (p<0,0001). CONCLUSÃO: Existiu uma associação entre a presença de Candida e EP, sendo C. albicans a espécie mais prevalente. Miconazol proveu melhores resultados na eliminação in vitro de colônias de Candida quando comparado à TFD.

Identification and characterization of nine atypical Candida dubliniensis clinical isolates

Candida dubliniensis is a pathogenic yeast of the genus Candida closely related to Candida albicans. The phenotypic similarity of these two species often leads to misidentification of C. dubliniensis isolates in clinical samples. DNA-based methods continue to be the most effective means of discriminating accurately between the two species. Here, we report on the identification of nine unusual Candida isolates that showed ambiguous identification patterns on the basis of their phenotypic and immunological traits. The isolates were categorized into two groups. Group I isolates were unable to produce germ tubes and chlamydospores, and to agglutinate commercial latex particles coated with a mAb highly specific for C. dubliniensis. Group II isolates grew as pink and white colonies on CHROMagar Candida and ChromID Candida, respectively. Carbohydrate assimilation profiles obtained with API/ID32C together with PCR amplification with specific primers and DNA sequencing allowed reliable identification of the nine unusual clinical isolates as C. dubliniensis.

Comparison of the efficacy of a novel sustained release clotrimazole varnish and clotrimazole troches for the treatment of oral candidiasis

OBJECTIVES

Candida albicans is a common fungal infection and is commensal in 40-65 % of healthy adults. The development and pharmacokinetics of a novel sustained release clotrimazole varnish (Clot-SRV) for topical oral use have been reported. The aim of this study was to compare the efficacy of this varnish with clotrimazole troche treatment of oral candidiasis.

MATERIALS AND METHODS

Of the 12 patients with denture stomatitis treated for 14 days, six used Clot-SRV (study group) and six clotrimazole troches (control). The patients were instructed to use Clot-SRV (50 mg of clotrimazole) once a day, and the control group was instructed to use five troches of 10 mg clotrimazole/day. Microbiological samples were obtained from saliva, buccal mucosa, palate, and denture. The degree of erythema was recorded at three time points, and subjective opinions noted using a questionnaire.

RESULTS

At the end of the study, the control group had relatively more cases of erythema on all examined surfaces; patients who applied the Clot-SRV had significantly lower levels of candida on the denture surfaces and in saliva, and had better compliance to the medication.

CONCLUSIONS

The novel clotrimazole sustained release varnish may be an important part of a new protocol for oral candidiasis, with improved clinical outcomes.

[Contribution of the chromogenic medium CHROMagar(®)Candida in mycological diagnosis of yeasts]

The incidence of invasive candidiasis has increased dramatically over the last decades due to a larger number of patients at risk. The diagnosis remains difficult as the clinical presentation is not specific and the biological diagnosis usually takes several days to become positive. We propose in this work through a prospective study to evaluate the contribution of a chromogenic medium CHROMagar(®) (Becton-Dickinson) in the mycological diagnosis of Candida. We selected 680 samples from patients hospitalized in the intensive care unit for epidemiological surveillance over a period of 11 weeks. We treated samples by culture on Sabouraud and on CHROMagar(®). The species identification was performed by chlamydosporulation test and carbohydrate assimilation tests. We found that the CHROMagar(®)Candida evaluated in our work was a valuable tool in the primary culture in differentiating the most frequently isolated yeast species and in better detection of mixed cultures.

Sertaconazole: an antifungal agent for the topical treatment of superficial candidiasis

Sertaconazole is a useful antifungal agent against mycoses of the skin and mucosa, such as cutaneous, genital and oral candidiasis and tinea pedis. Its antifungal activity is due to inhibition of the ergosterol biosynthesis and disruption of the cell wall. At higher concentrations, sertaconazole is able to bind to nonsterol lipids of the fungal cell wall, increasing the permeability and the subsequent death of fungal cells. Fungistatic and fungicidal activities on Candida are dose-dependent. The antifungal spectrum of sertaconazole includes deramophytes, Candida, Cryptococcus, Malassezia and also Aspergillus, Scedosporium and Scopulariopsis. Sertaconazole also shows an antimicrobial activity against streptococci, staphylococci and protozoa (Trichomonas). In clinical trials including patients with vulvovaginal candidiasis, a single dose of sertaconazole produced a higher cure rate compared with other topical azoles such as econazole and clotrimazole, in shorter periods. Sertaconazole has shown an anti-inflammatory effect that is very useful for the relief of unpleasant symptoms.

Occurrence of Candida species colonization in a population of denture-wearing immigrants

Infection of the oral cavity and dentures by Candida species are frequent in denture wearers. C. albicans is the most common pathogen; however, other emerging Candida species are also responsible for this condition. Few data are available about the occurrence of Candida species in the oral cavities of denture-wearing immigrants to Italy. In this study, we compare the Candida species found in the oral mucosa and on dentures from a population of denture wearing immigrants to Italy to a matched Italian group. Oral swabs were collected from dentures and the underlying mucosa of patients enrolled in the study and were then cultured to test for the presence of Candida species in each sample. Out of 168 patients enrolled (73 Italians and 95 immigrants), 51 Italians (69.8 percent) and 75 immigrants (78.9 percent) tested positive for the presence of Candida. Candida albicans was the most frequently observed species overall; however, we found a higher occurrence of C. glabrata among immigrants than among Italians. In addition, immigrants displayed a higher incidence of Candida – associated stomatitis and a lower mean age than Candida-positive individuals from the Italian group. Immigrants are more prone to longer colonization of the oral mucosa and dentures by Candida. In these patients, dentures must be checked periodically to prevent the presence of Candida.

Clinical evaluation of the essential oil of "Satureja Hortensis" for the treatment of denture stomatitis

BACKGROUND

The prevalence of denture stomatitis has been shown to vary from 15 to 65% in complete denture wearers. Satureja hortensis L. has been considered to have antinociceptive, anti-inflammatory, antifungal and antimicrobial activities in vitro and exhibits strong inhibitory effect on the growth of periodontal bacteria. The aim of this study was to evaluate the efficacy of a 1% gel formulation of S. hortensis essential oil for the treatment of denture stomatitis.

MATERIALS AND METHODS

A randomized, controlled clinical trial study was conducted on 80 patients (mean age 62.91±7.34) in two parallel groups treated either with S. hortensis essential oil 1% gel or placebo applied two times daily for two weeks. Denture stomatitis was diagnosed by clinical examination and paraclinical confirmation with sampling the palatal mucosa for Candida albicans. Data were analyzed using Chi-squared or Student's t tests.

RESULTS

The erythematous lesions of palatal area were significantly reduced (P<0.0001) in the treatment group who applied 1% topical gel of S. hortensis essential oil and Candida colonies count were reduced significantly (P=0.001).

CONCLUSION

Topical application of the essential oil of S. hortensis could be considered as an effective agent for the treatment of denture stomatitis.

Distribution Patterns of E-Cadherin, Type VII Collagen and Fibronectin in Denture-Related Stomatitis: A Preliminary Study

The distribution of epithelial E-cadherin, basement membrane type VII collagen, and underlying connective tissues fibronectin were investigated immunohistochemically and compared in normal palatal mucosa and in denture-related stomatitis (DRS) derivatives using monoclonal antibodies.Biopsies of palatal mucosa were obtained from twelve patients enrolled in this study, 8 with type II DRS and 4 with healthy mucosa.Our findings bring to the fore, using the expression of three components (E-cadherin, collagen type VII, fibronectin), the continuities of the disorder among epithelial, basement membrane and connective tissue in the case of DRS. In type II denture-related stomatitis, we found an expression of E-cadherinin all the strata of epithelia, and the diffuse and strong expression of type VII collagen at the interface between connective tissue and epithelial cells with discontinuities in BM. The strong expression of fibronectin in underlying connective tissue with penetration in some areas of the palatal mucosa may be an early consequence of advanced DRS. Nevertheless; no single change is pathognomonic of this inflammatory process.In normal tissues (healthy clinical aspect), E-cadherin was found to be restricted to the upper strata of the epithelia, and type VII collagen revealed thin linear staining in the basement membrane and fibronectin in underlying connective tissue combined epithelia.In the case of denture-related stomatitis DRS, these three markers reflect the immunohistological modifications from the superficial layer of the epithelium to the lamina propria.

In vitro activities of natural products against oral Candida isolates from denture wearers

Background

Candida-associated denture stomatitis is a frequent infectious disease. Treatment of this oral condition is difficult because failures and recurrences are common. The aim of this study was to test the in vitro antifungal activity of pure constituents of essentials oils.

Methods

Eight terpenic derivatives (carvacrol, farnesol, geraniol, linalool, menthol, menthone, terpinen-4-ol, and α-terpineol), a phenylpropanoid (eugenol), a phenethyl alcohol (tyrosol) and fluconazole were evaluated against 38 Candida isolated from denture-wearers and 10 collection Candida strains by the CLSI M27-A3 broth microdilution method.

Results

Almost all the tested compounds showed antifungal activity with MIC ranges of 0.03-0.25% for eugenol and linalool, 0.03-0.12% for geraniol, 0.06-0.5% for menthol, α-terpineol and terpinen-4-ol, 0.03-0.5% for carvacrol, and 0.06-4% for menthone. These compounds, with the exception of farnesol, menthone and tyrosol, showed important in vitro activities against the fluconazole-resistant and susceptible-dose dependent Candida isolates.

Conclusions

Carvacrol, eugenol, geraniol, linalool and terpinen-4-ol were very active in vitro against oral Candida isolates. Their fungistatic and fungicidal activities might convert them into promising alternatives for the topic treatment of oral candidiasis and denture stomatitis.

Microwave disinfection: cumulative effect of different power levels on physical properties of denture base resins

PURPOSE

This study evaluated the cumulative effects of different microwave power levels on the physical properties of two poly(methylmethacrylate) (PMMA) denture base resins.

MATERIALS AND METHODS

Eight sets of four PMMA specimens each (two polymerized in a water bath and two using microwave energy) were immersed in beakers containing 200 ml of distilled water. Each beaker was subjected to microwave irradiation for 3 minutes at a power level of 450,630, or 900 W. The surface roughness, surface hardness, linear stability, flexural strength, elastic modulus, impact strength, and fractographic properties were evaluated after either 6 or 36 simulated disinfection cycles. The data were statistically analyzed using ANOVA and the Tukey post hoc test (α= 0.05).

RESULTS

The polymerization method did not influence any property (p > 0.05) except linear stability. The surface roughness (p < 0.001) and hardness (p= 0.011) increased after 36 irradiation cycles at 630 or 900 W. The resin polymerized using microwave energy exhibited greater linear distortion (p= 0.012), and there was a cumulative effect on linear stability for both resins (p < 0.001). No significant change (p > 0.05) was observed in flexural strength; however, the elastic modulus decreased (p= 0.008) after 36 disinfection cycles. The impact strength and crack propagation angles displayed no significant differences (p > 0.05).

CONCLUSION

Within the limitations of this study, it can be concluded that microwave disinfection at 450 W to 630 W for 3 minutes is safe for PMMA.

Calcineurin controls drug tolerance, hyphal growth, and virulence in Candida dubliniensis

Candida dubliniensis is an emerging pathogenic yeast species closely related to Candida albicans and frequently found colonizing or infecting the oral cavities of HIV/AIDS patients. Drug resistance during C. dubliniensis infection is common and constitutes a significant therapeutic challenge. The calcineurin inhibitor FK506 exhibits synergistic fungicidal activity with azoles or echinocandins in the fungal pathogens C. albicans, Cryptococcus neoformans, and Aspergillus fumigatus. In this study, we show that calcineurin is required for cell wall integrity and wild-type tolerance of C. dubliniensis to azoles and echinocandins; hence, these drugs are candidates for combination therapy with calcineurin inhibitors. In contrast to C. albicans, in which the roles of calcineurin and Crz1 in hyphal growth are unclear, here we show that calcineurin and Crz1 play a clearly demonstrable role in hyphal growth in response to nutrient limitation in C. dubliniensis. We further demonstrate that thigmotropism is controlled by Crz1, but not calcineurin, in C. dubliniensis. Similar to C. albicans, C. dubliniensis calcineurin enhances survival in serum. C. dubliniensis calcineurin and crz1/crz1 mutants exhibit attenuated virulence in a murine systemic infection model, likely attributable to defects in cell wall integrity, hyphal growth, and serum survival. Furthermore, we show that C. dubliniensis calcineurin mutants are unable to establish murine ocular infection or form biofilms in a rat denture model. That calcineurin is required for drug tolerance and virulence makes fungus-specific calcineurin inhibitors attractive candidates for combination therapy with azoles or echinocandins against emerging C. dubliniensis infections.

Candida albicans or Candida dubliniensis?

Candida albicans is increasing as an opportunistic pathogen causing candidemia and candidiasis worldwide. In addition, other non-albicans Candida species are now also associated with pertinent infections. These include the closely related C. dubliniensis, which shares many phenotypic similarities with C. albicans. These similarities pose problems in the identification of isolates and have previously led to misidentification of these species. As a result, several identification techniques based on phenotypic and genotypic characteristics have been developed to differentiate between these Candida species. This review will focus on the similarities and differences between these two Candida species highlighting different identification methods and their advantages and disadvantages.