Candidiasis is a common infection primarily caused by the opportunistic fungus Candida albicans . Conventional antifungals have been associated with several limitations, and today, antimicrobial photodynamic therapy (aPDT) is raised as an adjuvant treatment. This study aimed to develop a carrier system for the photosensitizer methylene blue (MB) based on a gellan gum (GG) hydrogel, a nontoxic exopolysaccharide. Two formulations consisting of 0.6% and 1.0% (w/v) GG containing MB were prepared and characterized in relation to release kinetics, absorption spectroscopy, and optical shield formation. Then, the effects of MB GG formulations in aPDT using LED irradiation were evaluated against C. albicans. For this, aPDT was applied toC. albicans in planktonic and biofilm stages and also tested in a Galleria mellonella burn infection model. The successful incorporation of MB into the GG hydrogel was confirmed by absorption spectroscopy, with a characteristic peak at 660 nm for intact MB and both GG formulations. The GG0.6% hydrogel released 100% of MB in 12 min, whereas the GG1.0% hydrogel released only 75% of MB after 25 min. Furthermore, no optical shield formation was noticed with the MB gellan formulations in comparison to the aqueous form. In relation to antifungal activity on C. albicans, aPDT with GG0.6% and GG1.0% containing MB led to an eradication of planktonic cells and a partial reduction of biofilms, as observed in aPDT with MB aqueous. When aPDT was applied in G. mellonella larvae, an increase of 50% and 30% in survival rate was found, respectively, for the groups treated with MB gellan formulation and MB aqueous. In conclusion, the gellan gum formulations designed here were able to release MB and maintain its optical and photodynamic properties against C. albicans. In addition, aPDT with MB gellan formulations had higher in vivo efficacy than MB aqueous.

Natural compound-based strategies have gained attention as alternatives to conventional antifungal therapies, particularly in the management of Candida infections affecting the oral cavity, such as denture stomatitis. Our aim was to investigate the antifungal activity of the polyphenol pterostilbene (PTE) on clinical Candida isolates and microcosm biofilms from denture stomatitis, as well as to evaluate its toxicity and therapeutic efficacy in Galleria mellonella. PTE exhibited fungicidal effects against Candida albicans and Candida dubliniensis at 32 µg/mL. Time-kill assays demonstrated complete inhibition of viability for both strains within 8 h of exposure. In addition, PTE exhibited broad-spectrum antimicrobial activity, significantly reducing the counts of streptococci, mutans streptococci, staphylococci, and yeasts within microcosm biofilms. In vivo, PTE showed no signs of toxicity in G. mellonella at concentrations up to 20× MIC. Prophylactic treatment with PTE enhanced larval survival in experimental candidiasis caused by both C. albicans and C. dubliniensis. Moreover, prophylactic treatment decreased the fungal burden of C. albicans in the G. mellonella hemolymph, while the recruitment of hemocytes involved in host defense mechanisms remained unaltered. In summary, PTE demonstrated antimicrobial activity against Candida planktonic cells and complex biofilms associated with denture stomatitis, exhibiting favorable biocompatibility and in vivo antifungal efficacy in G. mellonella model.

Historically, the study of oral fungal species was limited by the inability to cultivate most of them. However, advances in metagenomic techniques have enabled the direct identification of microbial genomes from human samples, markedly broadening our understanding of the oral mycobiome. This literature review aims to analyze the available scientific evidence on the composition and dynamics of the oral mycobiome, as well as its influence on the development of local pathological conditions. The oral mycobiome is highly diverse, with emphasis on genus Candida, followed by Malassezia, Aspergillus, Saccharomyces, Cladosporium, Trichosporon and Geotrichum. Candida albicans remains the most frequently identified species in both health and diseases state. However, individuals with oral candidiasis present a higher detection of Candida dubliniensis, Candida parapsilosis, Pichia kudriavzevii, Antrodiella micra and Cladosporium sphaerospermum. In dental caries, C. albicans and C. dubliniensis are associated with advanced lesions, whereas Malassezia and Rhodotorula may exert protective effects against cariogenic bacteria. In periodontitis, an increase in yeast-bacteria interactions is observed. Additionally, C. albicans has been implicated in oral carcinogenesis through multiple mechanisms. These findings highlight the need for a deeper understanding of the oral mycobiome to enable early detection of oral diseases and the development of therapeutic approaches.

Historically, the study of oral fungal species was limited by the inability to cultivate most of them. However, advances in metagenomic techniques have enabled the direct identification of microbial genomes from human samples, markedly broadening our understanding of the oral mycobiome. This narrative review aims to analyze the available scientific evidence on the composition and dynamics of the oral mycobiome, as well as its influence on the development of local pathological conditions. The oral mycobiome is highly diverse, with emphasis on genus Candida, followed by Cladosporium, Aureobasidium and Saccharomyces. Candida albicans remains the most frequently identified species in both health and diseases state. However, individuals with oral candidiasis present a higher detection of Candida dubliniensis, Candida parapsilosis, Pichia kudriavzevii, Antrodiella micra and Cladosporium sphaerospermum. In dental caries, C. albicans and C. dubliniensis are associated with advanced lesions, whereas Debaryomyces and Rhodotorula may exert protective effects against Streptococcus mutans, a cariogenic bacterium. In periodontitis, an increase in yeast-bacteria interactions is observed. Additionally, C. albicans has been implicated in oral carcinogenesis through multiple mechanisms. These findings highlight the need for a deeper understanding of the oral mycobiome to enable early detection of oral diseases and the development of therapeutic approaches.

Antimicrobial photodynamic therapy (aPDT) has emerged as a promising strategy for managing infections associated withCandidaspp. In this context, nanoformulations of photosensitizers have been investigated to enhance the antimicrobial effects of established compounds, such as curcumin (CUR). In the present study, we evaluated the efficacy of aPDT mediated by curcumin-associated superparamagnetic iron oxide nanoparticles (CUR-SPION) and CUR againstCandidaspp. and complex heterotypic biofilms. Clinical samples were collected from the prosthesis surfaces and oral mucosa of 5 patients clinically diagnosed with denture stomatitis.Candidaisolates were identified using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS). CUR-SPION were synthesized via the coprecipitation method, allowing the incorporation and association of CUR with the nanoparticles during their formation. Subsequently, their size, morphology, stability, and surface charge were characterized. The isolates were then subjected to treatment with CUR and CUR-SPION, followed by aPDT using visible blue light (wavelength of 420 nm, power output of 1,250 mW, power density of 0.16 W/cm2, and energy density ranging from 0.79–12.78 J/cm2) in planktonic cultures, monotypic biofilms, and microcosm biofilms. Candidayeasts were detected in 3 patients and identified asC. albicansandC. dubliniensis. For both species, the minimum inhibitory concentration (MIC) of CUR was 64 μg/mL in the nonirradiated group and 4 μg/mL after aPDT. In contrast, CUR-SPION exhibited MIC values >64 μg/mL under all conditions tested. CUR-mediated aPDT decreasedCandidacell viability at 4 μg/mL and within 2 h of treatment by 3.6 log10 CFU/mL forC. dubliniensisP1, 3.2 log10 CFU/mL for C. albicans P2, and 2.0 log10 CFU/mL forC. dubliniensisP3, while CUR-SPION-aPDT showed no effect on biofilm viability. CUR-mediated aPDT also significantly reduced the viability of microcosm biofilms, causing inhibitions (log10 CFU/mL) of 1.3 to 2.2 for streptococci, 1.4 to 3.1 for mutans streptococci, 1.5 to 2.2 for staphylococci, and 1.2 to 3.1 for yeast. In conclusion, CUR-mediated aPDT was effective againstC. albicansandC. dubliniensisisolated from denture stomatitis, with an extended spectrum, targeting fungi and bacteria in microcosm biofilms. In contrast, CUR-SPION showed no antifungal activity againstCandidaunder the conditions tested.

Introdução: A estomatite protética é uma doença oral que resulta em processo inflamatório crônico da mucosa de suporte de uma prótese dentária, frequentemente associada à infecção por Candida. O tratamento da estomatite protética é dificultado pelo desenvolvimento de resistência das cepas de Candida aos fármacos antifúngicos. A terapia fotodinâmica antimicorbiana (TFDa), pode ser uma técnica alternativa que atua por meio de processos fotodinâmicos que resultam na produção de espécies reativas de oxigênio e morte dos microorganismos. Objetivo: Avaliar o efeito da TFDa mediada por curcumina (CUR) sobre Candida spp. isoladas de estomatite protética. Metodologia: O protocolo experimental foi aprovado pelo Comitê de Ética em Pesquisa com seres humanos do ICT/Unesp sob o número 5.827755. Foram coletadas amostras de 5 pacientes com estomatite protética e analisadas quanto à presença de Candida spp. pelo método de Gram e semeadura em Chromagar Candida. Após a confirmação da presença de Candida nas amostras, as espécies de Candida foram identificadas por meio de espectrometria de massa (MALDI-TOF). A seguir, foi determina a concentração inibitória mínima (CIM) da CUR para amostras de acordo com EUCAST E. DEF. 7.3.2. 2020. Após a determinação da CIM a TFDa foi testada sobre células planctônicas e biofilmes monoespécies das espécies de Candida isoladas. Após a TFDa sobre células planctônicas e biofilme monoespécie a viabilidade celular foi determinada pela contagem de unidades formadoras de colônias (UFC/ml). Resultados: Foi encontrada a presença de Candida nas amostras de 3 pacientes, que foram identificadas como P1, P2 e P3. Após a realização do MALDI-TOF foi identificada nas amostras P1 e P3, a espécie C. Dubliniensis e na amostra P2 foi encontrada C. albicans. A CIM de CUR foi de 64μg/ml na ausência de luz e de 4μg/ml na presença de luz. A atividade antimicrobiana da CUR sobre células planctônicas sugeriu que a CUR associada a TFDa apresenta ação fungistática. Os biofilmes monoespécies dessas cepas apresentaram redução significativa para todos os valores de CIM testados. Conclusão: A TFDa mediada por CUR foi eficaz contra cepas de C. albicans e C. dubliniensis isoladas de pacientes com estomatite protética, tendo efeitos antimicrobianos em culturas planctônicas e biofilmes monoespécies..