A protocol for an overview of systematic reviews to map photodynamic inactivation evidence in different dental specialties.

This is a protocol for an overview to summarize the findings of Systematic Reviews (SR) dealing with Photodynamic Inactivation (PDI) for control of oral diseases. Specific variables of oral infectious will be considered as outcomes, according to dental specialty. Cochrane Database of Systematic Reviews (CDSR), MEDLINE, LILACS, Embase, and Epistemonikos will be searched, as well as reference lists. A search strategy was developed for each database using only terms related to the intervention (PDI) aiming to maximize sensitivity. After checking for duplicate entries, selection of reviews will be performed in a two-stage technique: two authors will independently screening titles and abstracts, and then full texts will be assessed for inclusion/exclusion criteria. Any disagreement will be resolved through discussion and/or consultation with a third reviewer. Data will be extracted following the recommendations in Chapter V of Cochrane Handbook and using an electronic pre-specified form. The evaluation of the methodological quality and risk of bias (RoB) of the SR included will be carried out using the AMSTAR 2 and ROBIS. Narrative summaries of relevant results from the individual SR will be carried out and displayed in tables and figures. A specific summary will focus on PDI parameters and study designs, such as the type and concentration of photosensitizer, pre-irradiation time, irradiation dosimetry, and infection or microbiological models, to identify the PDI protocols with clinical potential. We will summarize the quantitative results of the SRs narratively.

Antimicrobial Activity of Curcumin in Nanoformulations: A Comprehensive Review.

Curcumin (CUR) is a natural substance extracted from turmeric that has antimicrobial properties. Due to its ability to absorb light in the blue spectrum, CUR is also used as a photosensitizer (PS) in antimicrobial Photodynamic Therapy (aPDT). However, CUR is hydrophobic, unstable in solutions, and has low bioavailability, which hinders its clinical use. To circumvent these drawbacks, drug delivery systems (DDSs) have been used. In this review, we summarize the DDSs used to carry CUR and their antimicrobial effect against viruses, bacteria, and fungi, including drug-resistant strains and emergent pathogens such as SARS-CoV-2. The reviewed DDSs include colloidal (micelles, liposomes, nanoemulsions, cyclodextrins, chitosan, and other polymeric nanoparticles), metallic, and mesoporous particles, as well as graphene, quantum dots, and hybrid nanosystems such as films and hydrogels. Free (non-encapsulated) CUR and CUR loaded in DDSs have a broad-spectrum antimicrobial action when used alone or as a PS in aPDT. They also show low cytotoxicity, in vivo biocompatibility, and improved wound healing. Although there are several in vitro and some in vivo investigations describing the nanotechnological aspects and the potential antimicrobial application of CUR-loaded DDSs, clinical trials are not reported and further studies should translate this evidence to the clinical scenarios of infections.

Photodithazine-mediated antimicrobial photodynamic therapy against fluconazole-resistant Candida albicans in vivo.

This study evaluated the efficacy of antimicrobial Photodynamic Therapy (aPDT) against fluconazole-resistant Candida albicans in a murine model of oral candidosis. Mice were inoculated with two clinical isolates (R10, R15) and one reference strain (ATCC) of resistant C. albicans to produce oral candidosis. After inoculation, aPDT mediated by Photodithazine® (PDZ) and LED light was performed. The use of PDZ or light only was also investigated. Additional animals were treated with Nystatin (NYS). Untreated or healthy mice were also evaluated. Microbiological evaluation was performed by recovering C. albicans from the tongue via colony-forming units. Animals were killed 24 hours after treatments, and the tongues were removed for histological analysis. Data were analyzed by one-way ANOVA and Tukey test (P < .05). The results demonstrated that all strains showed the same behavior after aPDT and NYS treatment. A significant reduction in C. albicans viability was achieved after both treatments for R15 and ATCC. No significant reduction was verified for C. albicans R10 submitted to aPDT or NYS. The histological analysis revealed that aPDT did not cause side effects on tissues. aPDT was effective for inactivation of two fluconazole-resistant C. albicans of the three strains evaluated.

Antimicrobial sonodynamic and photodynamic therapies against Candida albicans.

Candida albicans biofilms exhibit unique characteristics and are highly resistant to antifungal agents. Antimicrobial photodynamic therapy (aPDT) is an alternative treatment limited to treating superficial infections due to the poor light penetration. In this manuscript, the antifungal properties of sonodynamic therapy (SDT) were assessed. SDT uses ultrasound instead of light, enabling the treatment of deeper infections. Planktonic cells and biofilms of C. albicans were treated with aPDT or SDT, in addition to combined aPDT/SDT, with cell survival determined using colony forming units. The total biomass and structural integrity of the biofilms were also investigated. The results demonstrated that while individual aPDT or SDT eradicated suspensions, they had little impact on biofilms. However, combined aPDT/SDT significantly reduced the viability and total biomass of biofilms. Microscopic images revealed that biofilms treated with aPDT/SDT were thinner and comprised mainly of dead cells. These results highlight the potential of combined aPDT/SDT for the inactivation of C. albicans biofilms.

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.

Antimicrobial Photodynamic Therapy Mediated by Curcumin-Loaded Polymeric Nanoparticles in a Murine Model of Oral Candidiasis.

Antimicrobial photodynamic therapy (aPDT) has been proposed as an alternative method for oral candidiasis (OC), while nanocarriers have been used to improve the water solubility of curcumin (CUR). The aim of this study is to encapsulate CUR in polymeric nanoparticles (NPs) and to evaluate its photodynamic effects on a murine model of OC. Anionic and cationic CUR-NP is synthesized using poly-lactic acid and dextran sulfate and then characterized. Female mice are immunosuppressed and inoculated with Candida albicans (Ca) to induce OC. aPDT is performed by applying CUR-NP or free CUR on the dorsum of the tongue, followed by blue light irradiation for five consecutive days. Nystatin is used as positive control. Afterward, Ca are recovered and cultivated. Animals are euthanized for histological, immunohistochemical, and DNA damage evaluation. Encapsulation in NP improves the water solubility of CUR. Nystatin shows the highest reduction of Ca, followed by aPDT mediated by free CUR, which results in immunolabelling of cytokeratins closer to those observed for healthy animals. Anionic CUR-NP does not show antifungal effect, and cationic CUR-NP reduces Ca even in the absence of light. DNA damage is associated with Ca infection. Consecutive aPDT application is a safe treatment for OC.

Cytotoxicity of antimicrobial photodynamic inactivation on epithelial cells when co-cultured with Candida albicans.

This study assessed the cytotoxicity of antimicrobial Photodynamic Inactivation (aPDI), mediated by curcumin, using human keratinocytes co-cultured with Candida albicans. Cells and microorganisms were grown separately for 24 hours and then kept in contact for an additional 24 hours. After this period, aPDI was applied. The conditions tested were: P+L+ (experimental group aPDI); P-L+ (light emitting diode [LED] group); P+L- (curcumin group); and P-L- (cells in co-culture without curcumin nor LED). In addition, keratinocytes and C. albicans were grown separately, were not placed in the co-culture and did not receive aPDI (control group). Cell proliferation was assessed using Alamar Blue, MTT, XTT and CFU tests. Qualitative and quantitative analyses were performed. Analysis of variance (ANOVA) was applied to the survival percentages of cells compared to the control group (considered as 100% viability), complemented by multiple comparisons using Tukey's test. A 5% significance level was adopted. The results of this study showed no interference in the metabolism of the cells in co-culture, since no differences were observed between the control group (cultured cells by themselves) and the P-L- group (co-culture cells without aPDI). The aPDI group reached the highest reduction (p = 0.009), which was equivalent to 1.7 log10 when compared to the control group. The P+L-, P-L+, P-L- and control groups were not statistically different (ρ > 0.05). aPDI inhibited the growth of keratinocytes and C. albicans in all tests, so the therapy was considered slightly (inhibition between 25 and 50% compared to the control group) to moderately (inhibition between 50 and 75% compared to the control group) cytotoxic.

Photodynamic inactivation of a multispecies biofilm using Photodithazine(®) and LED light after one and three successive applications.

In this investigation, the effectiveness of successive applications of antimicrobial photodynamic inactivation (API) mediated by Photodithazine(®) (PDZ) and LED light was evaluated against a multispecies biofilm formed by Candida albicans, Candida glabrata, and Streptococcus mutans on denture base acrylic resin. Standard cell suspensions (bacteria and yeast) were inoculated on acrylic resin samples, and the biofilm was grown for 48 h (37 °C/75 rpm). API was performed by the administration of PDZ (175 and 200 mg/L) and exposure to 37.5 J/cm(2) of LED light (660 nm). Additional samples were treated with PDZ or LED light only. Untreated control samples were not submitted to light or PDZ. The conditions described were applied once or in three consecutive applications for all groups. Cell viability was determined by colony counts (CFU/mL), metabolic activity, total biomass, and confocal laser scanning microscopy (CLSM). Data were analyzed by a nonparametric two-way ANOVA and Tukey tests (α = 0.05). The results obtained demonstrated a significant effect (p < 0.05) of number of applications and treatment groups for CFU/mL, and S. mutans showed the highest susceptibility to API. The metabolic activity of the multispecies biofilm was significantly reduced (p < 0.05) after API for both numbers of applications, which were also significantly different (p < 0.05) between them. The total biomass of the biofilm was significantly different (p < 0.05) only between groups submitted to one and three API applications. CLSM showed a visual increase of dead cells after API. API-mediated PDZ was effective in reducing the cell viability of multispecies biofilm. Three consecutive applications of API were more effective for reducing the cell viability and the total biomass of multispecies biofilm.

Susceptibility of multispecies biofilm to photodynamic therapy using Photodithazine®.

This in vitro study evaluated the effect of photodynamic therapy (PDT) on the multispecies biofilm of Candida albicans, Candida glabrata, and Streptococcus mutans. Standardized fungal and bacterial suspensions were cultivated appropriately for each species and inoculated in 96-well microtiter plates for mix-biofilm formation. After 48 h of incubation, the biofilms were submitted to PDT (P + L+) using Photodithazine® (PDZ) at 100, 150, 175, 200, or 250 mg/mL for 20 min and 37.5 J/cm(2) of light-emitting diode (LED) (660 nm). Additional samples were treated only with PDZ (P + L-) or LED (P-L+), or neither (control, P-L-). Afterwards, the biofilms were evaluated by quantification of colonies (CFU/mL), metabolic activity (XTT reduction assay), total biomass (crystal violet staining), and confocal scanning laser microscopy (CSLM). Data were analyzed by one-way ANOVA and Tukey tests (p < 0.05). Compared with the control, PDT promoted a significant reduction in colonies viability of the three species evaluated with 175 and 200 mg/mL of PDZ. PDT also significantly reduced the metabolic activity of the biofilms compared with the control, despite the PDZ concentration. However, no significant difference was found in the total biomass of samples submitted or not to PDT. For all analysis, no significant difference was verified among P-L-, P + L-, and P-L+. CSLM showed a visual increase of dead cells after PDT. PDT-mediated PDZ was effective in reducing the cell viability of multispecies biofilm.

Curcuminoid-Mediated Antimicrobial Photodynamic Therapy on a Murine Model of Oral Candidiasis.

Antimicrobial Photodynamic Therapy (aPDT) has been extensively investigated in vitro, and preclinical animal models of infections are suitable for evaluating alternative treatments prior to clinical trials. This study describes the efficacy of aPDT in a murine model of oral candidiasis. Forty mice were immunosuppressed with subcutaneous injections of prednisolone, and their tongues were inoculated using an oral swab previously soaked in a C. albicans cell suspension. Tetracycline was administered via drinking water during the course of the experiment. Five days after fungal inoculation, mice were randomly distributed into eight groups; a ninth group of untreated uninfected mice was included as a negative control (n = 5). Three concentrations (20 µM, 40 µM, and 80 µM) of a mixture of curcuminoids were tested with a blue LED light (89.2 mW/cm2; ~455 nm) and without light (C+L+ and C+L- groups, respectively). Light alone (C-L+), no treatment (C-L-), and animals without infection were evaluated as controls. Data were analyzed using Welch's ANOVA and Games-Howell tests (α = 0.05). Oral candidiasis was established in all infected animals and visualized macroscopically through the presence of characteristic white patches or pseudomembranes on the dorsum of the tongues. Histopathological sections confirmed a large presence of yeast and filaments limited to the keratinized layer of the epithelium in the C-L- group, and the presence of fungal cells was visually decreased in the images obtained from mice subjected to aPDT with either 40 µM or 80 µM curcuminoids. aPDT mediated by 80 µM curcuminoids promoted a 2.47 log10 reduction in colony counts in comparison to those in the C-L- group (p = 0.008). All other groups showed no statistically significant reduction in the number of colonies, including photosensitizer (C+L-) or light alone (C-L+) groups. Curcuminoid-mediated aPDT reduced the fungal load from the tongues of mice.

DNase improves the efficacy of antimicrobial photodynamic therapy in the treatment of candidiasis induced with Candida albicans.

The study evaluated the association of DNase I enzyme with antimicrobial photodynamic therapy (aPDT) in the treatment of oral candidiasis in mice infected with fluconazole-susceptible (CaS) and -resistant (CaR) Candida albicans strains. Mice were inoculated with C. albicans, and after the infection had been established, the tongues were exposed to DNase for 5 min, followed by photosensitizer [Photodithazine®(PDZ)] and light (LED), either singly or combined. The treatments were performed for 5 consecutive days. Treatment efficacy was evaluated by assessing the tongues via fungal viable population, clinical evaluation, histopathological and fluorescence microscopy methods immediately after finishing treatments, and 7 days of follow-up. The combination of DNase with PDZ-aPDT reduced the fungal viability in mice tongues immediately after the treatments by around 4.26 and 2.89 log10 for CaS and CaR, respectively (versus animals only inoculated). In the fluorescence microscopy, the polysaccharides produced by C. albicans and fungal cells were less labeled in animals treated with the combination of DNase with PDZ-aPDT, similar to the healthy animals. After 7 days of the treatment, DNase associated with PDZ-aPDT maintained a lower count, but not as pronounced as immediately after the intervention. For both strains, mice treated with the combination of DNase with PDZ-aPDT showed remission of oral lesions and mild inflammatory infiltrate in both periods assessed, while animals treated only with PDZ-aPDT presented partial remission of oral lesions. DNase I enzyme improved the efficacy of photodynamic treatment.

Photo-responsive polymeric micelles for the light-triggered release of curcumin targeting antimicrobial activity.

Nanocarriers have been successfully used to solubilize, deliver, and increase the bioavailability of curcumin (CUR), but slow CUR release rates hinder its use as a topical photosensitizer in antimicrobial photodynamic therapy. A photo-responsive polymer (PRP) was designed for the light-triggered release of CUR with an effective light activation-dependent antimicrobial response. The characterization of the PRP was compared with non-responsive micelles comprising Pluronics™ P123 and F127. According to the findings, the PRP formed photo-responsive micelles in the nanometric scale (< 100 nm) with a lower critical micelle concentration (3.74 × 10-4 M-1, 5.8 × 10-4 M-1, and 7.2 × 10-6 M-1 for PRP, F127, P123, respectively, at 25°C) and higher entrapment efficiency of CUR (88.7, 77.2, and 72.3% for PRP, F127, and P123 micelles, respectively) than the pluronics evaluated. The PRP provided enhanced protection of CUR compared to P123 micelles, as demonstrated in fluorescence quenching studies. The light-triggered release of CUR from PRP occurred with UV light irradiation (at 355 nm and 25 mW cm-2) and a cumulative release of 88.34% of CUR within 1 h compared to 80% from pluronics after 36 h. In vitro studies showed that CUR-loaded PRP was non-toxic to mammal cell, showed inactivation of the pathogenic microorganisms Candida albicans, Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus, and decreased biofilm biomass when associated with blue light (455 nm, 33.84 J/cm2). The findings show that the CUR-loaded PRP micelle is a viable option for antimicrobial activity.

Photodynamic inactivation of microorganisms present on complete dentures. A clinical investigation. Photodynamic disinfection of complete dentures.

The aim of this study was to evaluate the effectiveness of photodynamic therapy (PDT) for the disinfection of complete dentures. Biofilm samples were collected from dentures of 60 denture users who were randomly divided into four experimental groups (n = 15 each): subjects whose maxillary dentures were sprayed with 50 and 100 mg/l of Photogem® suspension (groups P50S and P100S) and patients whose maxillary dentures were treated with 50 and 100 mg/l of Photogem® gel (groups P50G and P100G). Dentures with photosensitizers were left in the dark for 30 min (pre-irradiation time) and then irradiated with blue LED light at 37.5 J/cm(2) (26 min). Denture samples were taken with sterile cotton swab before (left side surfaces) and after (right side surfaces) PDT. All microbial material was diluted and plated on selective media for Candida spp., Staphylococcus mutans spp., streptococci and a non-selective media. After incubation (48 h/37°C), the number of colony-forming units (cfu/ml) was counted. Microorganisms grown on selective media were identified using biochemical methods before and after PDT. The data were submitted to McNemar and Kruskal-Wallis tests (α = 0.05). No growth after PDT was observed in 60, 53, 47, and 40% of dentures from P100G, P50G, P100S, and P50S groups, respectively. When evidence of microorganisms' growth was observed, PDT regimens eliminated over 90% of microorganisms on dentures. This clinical study showed that PDT was effective for disinfecting dentures.

A Denture Use Model Associated with Candida spp. in Immunocompetent Male and Female Rats.

Denture stomatitis (DS) is a common infection in denture wearers, especially women. This study evaluated the induction of DS using acrylic devices attached to the palate of rats combined with inoculation of Candida spp. Immunocompetent male and female rats received a carbohydrate-rich diet. Impressions were taken from the rats' palate to individually fabricate acrylic devices. Mono- and multispecies biofilms of C. albicans, C. glabrata, and C. tropicalis were grown on the devices, which were then cemented on posterior teeth and kept in the rats' palate for four weeks. Microbial samples from the palate and the device were quantified. Oral microbiome of rats inoculated with C. albicans was analyzed by 16S rRNA gene sequencing. Log10(CFU/mL) were analyzed by mixed or two-way MANOVA (α = 0.05). Candida spp. and acrylic device did not induce palatal inflammation macroscopically nor microscopically. Although there was an increase (p < 0.001) of the total microbiota and female rats demonstrated higher (p = 0.007) recovery of Candida spp. from the palate, the gender differences were not biologically relevant. The microbiome results indicate an increase in inflammatory microbiota and reduction in health-associated micro-organisms. Although Candida spp. and acrylic device did not induce DS in immunocompetent rats, the shift in microbiota may precede manifestation of inflammation.

Efficacy of curcumin-mediated antibacterial photodynamic therapy for oral antisepsis: A systematic review and network meta-analysis of randomized clinical trials.

BACKGROUND: The presence of oral microorganisms resistant to traditional treatment is increasing, thus a search for new therapies is needed. In this context, antimicrobial photodynamic therapy (aPDT) is an approach for the treatment of antibiotic resistant andnon resistant microorganisms. Therefore, the aim of the present study was to conduct a systematic review and meta-analysis of randomized clinical trials of aPDT for oral antisepsis against oral polymicrobial biofilms. METHODS: PubMed, Science Direct, Scopus, SciELO, Lilacs, Cochrane Library and Embase databases were searched. In total, five articles were included for qualitative analysis and four articles were used for quantitative analyses. Bias assessment of the eligible articles was made using the RoB 2 criteria. Network meta-analysis was performed using the random-effect model. Subgroup's analysis was also conducted. The groups evaluated were aPDT, exposure to light only and no treatment at all (control group). The quality of evidence was assessed by CINeMA approach. RESULTS: aPDT mediated by curcumin had significant results in the reducing bacterial load (0.31-0.49 log10 UFC/ I2=0%) when compared with the control group. The included articles were classified as low risk of bias, despite biases detected by allocation and blinding. Moreover, quantitative analysis between aPDT and control group and between light and control group were classified with low risk of confidence rating, while the results from aPDT versus light were classified as moderate risk of confidence rating. CONCLUSION: aPDT has significant efficacy for oral antisepsis, however more randomized clinical trials will be needed to validate the present results.

Efficacy of Antimicrobial Photodynamic Therapy Mediated by Photosensitizers Conjugated with Inorganic Nanoparticles: Systematic Review and Meta-Analysis.

Antimicrobial photodynamic therapy (aPDT) is a method that does not seem to promote antimicrobial resistance. Photosensitizers (PS) conjugated with inorganic nanoparticles for the drug-delivery system have the purpose of enhancing the efficacy of aPDT. The present study was to perform a systematic review and meta-analysis of the efficacy of aPDT mediated by PS conjugated with inorganic nanoparticles. The PubMed, Scopus, Web of Science, Science Direct, Cochrane Library, SciELO, and Lilacs databases were searched. OHAT Rob toll was used to assess the risk of bias. A random effect model with an odds ratio (OR) and effect measure was used. Fourteen articles were able to be included in the present review. The most frequent microorganisms evaluated were Staphylococcus aureus and Escherichia coli, and metallic and silica nanoparticles were the most common drug-delivery systems associated with PS. Articles showed biases related to blinding. Significant results were found in aPDT mediated by PS conjugated with inorganic nanoparticles for overall reduction of microorganism cultured in suspension (OR = 0.19 [0.07; 0.67]/p-value = 0.0019), E. coli (OR = 0.08 [0.01; 0.52]/p-value = 0.0081), and for Gram-negative bacteria (OR = 0.12 [0.02; 0.56/p-value = 0.0071). This association approach significantly improved the efficacy in the reduction of microbial cells. However, additional blinding studies evaluating the efficacy of this therapy over microorganisms cultured in biofilm are required.

Fungicidal effect of photodynamic therapy against fluconazole-resistant Candida albicans and Candida glabrata.

Although photodynamic therapy (PDT) has shown great promise for the inactivation of Candida species, its effectiveness against azole-resistant pathogens remains poorly documented. This in vitro study describes the association of Photogem® (Photogem, Moscow, Russia) with LED (light emitting diode) light for the photoinactivation of fluconazole-resistant (FR) and American Type Culture Collection (ATCC) strains of Candida albicans and Candida glabrata. Suspensions of each Candida strain were treated with five Photogem® concentrations and exposed to four LED light fluences (14, 24, 34 or 50 min of illumination). After incubation (48 h at 37 °C), colonies were counted (CFU ml(-1)). Single-species biofilms were generated on cellulose membrane filters, treated with 25.0 mg l(-1) of Photogem® and illuminated at 37.5 J cm(-2). The biofilms were then disrupted and the viable yeast cells present were determined. Planktonic suspensions of FR strains were effectively killed after PDT. It was observed that the fungicidal effect of PDT was strain-dependent. Significant decreases in biofilm viability were observed for three strains of C. albicans and for two strains of C. glabrata. The results of this investigation demonstrated that although PDT was effective against Candida species, fluconazole-resistant strains showed reduced sensitivity to PDT. Moreover, single-species biofilms were less susceptible to PDT than their planktonic counterparts.

Effectiveness of chlorhexidine on the disinfection of complete dentures colonised with fluconazole-resistant Candida albicans: in vitro study.

This in vitro study evaluated different concentrations of chlorhexidine (CHX) solution on the disinfection of dentures colonised with a reference (ATCC 90028) and azole-resistant (R1, R2 e R3) strains of Candida albicans. Sterile dentures were individually inoculated with one of the strains and incubated at 37 °C for 24 h. Then, each denture was immersed in sterile saline (control) or CHX (2%, 1% or 0.2%) for 10 min. Samples of serial dilutions were spread on Agar Sabouraud Dextrose and incubated at 37 °C for 48 h. The colonies were counted and the values of log(cfu ml(-1)) were analysed by Kruskal-Wallis test (P < 0.05). Dentures immersed in CHX were incubated for 7 days. For all strains, the cfu ml(-1) values of 0.2% CHX were significantly higher than those of 2% and 1% CHX. There was no difference between the cfu ml(-1) values of 2% and 1% CHX. For dentures immersed in CHX, ATCC 90028 strain showed lower cfu ml(-1) values than R2 and R3 strains. For control dentures, cfu ml(-1) values of ATCC 90028 strain were higher than those of R strains. Immersion in 2% CHX resulted in the highest number of dentures without fungal growth after 7 days. For denture disinfection, 2% CHX was the most effective concentration, and R strains were less susceptible to disinfection. Chlorhexidine is effective in disinfection of dentures contaminated with azole-resistant C. albicans.

Verapamil inhibits efflux pumps in Candida albicans, exhibits synergism with fluconazole, and increases survival of Galleria mellonella.

The emergence of resistance requires alternative methods to treat Candida albicans infections. We evaluated efficacy of the efflux pump inhibitor (EPI) verapamil (VER) with fluconazole (FLC) against FLC-resistant (CaR) and -susceptible C. albicans (CaS). The susceptibility of both strains to VER and FLC was determined, as well as the synergism of VER with FLC. Experiments were performed in vitro for planktonic cultures and biofilms and in vivo using Galleria mellonella. Larval survival and fungal recovery were evaluated after treatment with VER and FLC. Data were analyzed by analysis of variance and Kaplan-Meier tests. The combination of VER with FLC at sub-lethal concentrations reduced fungal growth. VER inhibited the efflux of rhodamine 123 and showed synergism with FLC against CaR. For biofilms, FLC and VER alone reduced fungal viability. The combination of VER with FLC at sub-lethal concentrations also reduced biofilm viability. In the in vivo assays, VER and FLC used alone or in combination increased the survival of larvae infected with CaR. Reduction of fungal recovery was observed only for larvae infected with CaR and treated with VER with FLC. VER reverted the FLC-resistance of C. albicans. Based on the results obtained, VER reverted the FLC-resistance of C. albicans and showed synergism with FLC against CaR. VER also increased the survival of G. mellonella infected with CaR and reduced the fungal recovery.

A randomized clinical trial evaluating Photodithazine-mediated Antimicrobial Photodynamic Therapy as a treatment for Denture stomatitis.

OBJECTIVE: This randomized clinical trial assessed antimicrobial Photodynamic Therapy (aPDT) mediated by Photodithazine (PDZ) to treat patients with denture stomatitis (DS). METHODOLOGIES: Patients with DS were randomly assigned to the groups: aPDT (n = 30) and nystatin (NYS, n = 35). aPDT patients received 6 aPDT sessions, three times a week for 15 days, which involved PDZ (200 mg/L) topical application (20 min) on the palate and upper denture, followed by LED illumination (660 nm, 50 J/cm²). NYS patients were instructed to rinse one dropper of this medication for one minute, four times a day, for 15 days. Microbiological collections of dentures and palates were performed and cultured on blood agar and CHROMAgar Candida. Microbial viability was determined, and photographs of the palates were taken for clinical evaluation. Data were analyzed by Repeated Measure Linear Model and Bonferroni (p ≤ 0.05). RESULTS: aPDT was more effective to reduce the total microbiota than NYS. At the end of the treatments, aPDT reduced 1.98 from the palate and 1.91 log10 from the denture, while NYS reduced 0.05 and 0.17 log10, respectively. Moreover, aPDT was as effective as NYS to reduce Candida. Reductions of 0.68 and 0.77 log10 were observed in the palate and denture of aPDT group, while reductions of 0.57 and 1.43 log10 were achieved in the NYS group, respectively. Regarding to oral lesion, 53.3 and 54.2 % of the patients from aPDT and NYS groups had clinical improvement. However, the recurrence of DS was observed in both groups. CONCLUSION: PDZ-mediated aPDT is a promising treatment for DS.