Some oral manifestations have been observed in patients with coronavirus disease 2019 (COVID-19). However, there is still a question about whether these lesions are due to coronavirus infection or secondary manifestations resulting from the patient's systemic condition. Thus, this article aims to report an additional case of an oral condition in a patient diagnosed with COVID-19. Our patient, a sixty-sevenyear-old Caucasian man, tested positive to coronavirus and presented oral manifestations such as recurrent herpes simplex, candidiasis, and geographic tongue. We support the argument that some oral conditions could be secondary to the deterioration of systemic health or due to treatments for COVID-19. The present case report highlights the importance of including dentists in the intensive care unit multiprofessional team to improve oral health in critical patients, not only COVID-19 patients, but also, to contribute to evidence-based and decision-making in managing infectious diseases.

Candidiasis or oral candidiasis is a disease most commonly caused by Candida albicans, present in the microbiota as commensals, it is an opportunistic infection being observed mainly in immunocompromised patients. It is estimated that approximately 50% of the healthy population carries Candida species in the oral cavity. In the treatment of mild oral candidiasis, azole or polyene antifungals are highlighted. The adverse effects and cost of conventional antifungal treatment have led to the search for new drugs, one of the alternatives being terpenes. Extracted from essential oils are complex mixtures of various compounds, myrtenol being an example. In this work, the activity of myrtenol against fluconazole resistant Candida strains was verified. Minimum inhibitory concentration, minimum fungicidal concentration, in addition to modulation and association studies (checkerboard method) were performed via the microdilution technique. With the strains tested, myrtenol demonstrated minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) at concentrations of 512 μg/mL, so it has weak antifungal activity and is fungicidal. In the assay of modulation of myrtenol in subinhibitory concentration with the main antifungal agents, there was an increase in the MIC of these drugs. When myrtenol was associated with these antifungal agents (checkboard method), synergistic or indifferent results were observed with fluconazole or amphotericin B, respectively. Myrtenol has weak antifungal activity against the strains tested, but with a fungicidal characteristic, it does not increase the activity of fluconazole and amphotericin B and, in association with conventional antifungal agents, it showed a synergistic or indifferent effect depending on the strain tested.

Diabetic individuals may present oral manifestations due to high glucose levels, that favors the development of more pathogenic biofilms in the presence of microorganisms such as Candida albicans and Streptococcus mutans. The aim of the study was analyze the effect of different glucose levels simulating different salivary conditions in C. albicans (ATCC 90028) and S. mutans (UA159) duoespecies biofilms in acrylic resins. Initially, a salivary film was developed and standardized or absorbed 600nm. Then, the biofilm cells were cultured for 96 hours on acrylic resin samples. They were subjected to constant exposures of glucose equivalent to 0, 20, 60 and 100 mM salivary levels and were in contact with 10% sucrose three times daily. Colony forming units (CFU / mL), soluble and insoluble extracellular polysaccharides (SEPS and IEPS), biomass, total protein (TP), phospholipase activity and fluorescence morphology analysis were performed. The acidogenicity of the culture medium was also measured. Data were analyzed by ANOVA / Tukey and Kruskal-Wallis / Mann-Whitney (α= 5%). The CFU / mL result for C. albicans determines media between 8.50 ± 0.23 and 8.97 ± 0.24, with significant difference between groups p <0.00. For the S. mutans count, there was a difference between 0 and 20mM (p <0.01). The other variables showed no differences between them (p> 0.05). Regarding PECs, wet weight and phospholipase production without differences (p> 0.05), despite the high proteolytic activity. For IEPS, there were differences between the 20 and 60 mM groups (p <0.01). For the TP test, there were differences between minor and major. Regarding morphology, collocalization between species was observed. The culture medium maintains acid throughout the days of use (5.6 ± 0.5). We conclude that glucose from salivary levels may interfere in the pathogenicity of C. albicans and S. mutans biofilms in acrylic resin substrates.

Objective: To evaluate the antifungal potential of 2-Bromo-N-phenylacetamide (A1Br) against oral cavity C. glabrata; Materials and methods: An in vitro laboratory study using an inductive approach was performed. Assays to evaluate the antifungal activity of A1Br, nystatin and miconazole against C. glabrata strains were performed using microdilution technique. Minimum Inhibitory (MIC), and Minimum Fungicide (MFC) Concentrations were determined, as well as evaluation of yeast structures and association tests of the molecule with standard antifungals. Results: The A1Br molecule presented an MIC of 16 μg/mL and an MFC of 32-64 μg/mL; revealing antifungal potential similar to nystatin (MIC 8 μg/mL and MFC 8- 32 μg/mL) and superior to miconazole (MIC 64 g/mL and MFC of 512-1024 g/mL). The A1Br - nystatin association presented antifungal effect. The A1Br - miconazole association presented fungistatic effect. Micromorphological evaluation revealed decreases in all structures for the two studied strains at the antifungal concentration of A1Br =MIC x 2, reaching 100% at A1Br = MIC x 4. The association study with nystatin revealed antagonism (FICI = 4.5) and with miconazole revealed indifference (FICI = 1.25). Conclusion: The studied molecule presents excellent antifungal effect against C.glabrata. Clinical Relevance: The search for new products and formulations is based on a great necessity for more alternatives against the fungi which cause oral C.glabrata infections. Despite the excellent antifungal activity potential of the studied molecule, further studies are needed to evaluate mechanisms of action and associations with other substances.

Introduction: Oral candidiasis represents one of the greatest challenges to be faced by dentistry, either because of the limited number of antifungal agents available or because of the expressive resistance presented by microorganisms involved in this type of infection. Objective: This study evaluated the effectiveness of a mouthwash and a spray containing essential oil (EO) extracted from leaves of Cinnamomum zeylanicum Blume (cinnamon) in the treatment of bucal candidosis associated with the use of dental prosthesis. Methodology: A randomized, double blinded, controlled clinical trial was conducted in a probabilistic sample of 36 participants with the disease, divided into two groups that used the experimental solution (C. zeylanicum, n = 18) and control (nystatin, n = 18). Mycological and clinical parameters were evaluated, by a calibrated examiner, before and after 15 days of use of the products. A count of the Colony Forming Units (CFU) of Candida spp. of the biological samples collected with a swab on the palate and on the prosthesis of the patients was done before and after treatment. Data were analyzed by descriptive and inferential statistical analyzes, based on mycological and clinical parameters, considering α = 5%. Results: The clinical examination of the affected mucosa showed that the products containing C. zeylanicum EO (p = 0.0339) and nystatin (p = 0.0139) promoted clinical efficacy, with significant reduction of signs and symptoms observed. The mycological analysis expressed by the number of CFU indicated that the EO of C. zeylanicum had no significant effect (p> 0.05) on the reduction of Candida spp. isolated from the mucosa and dental prosthesis. Nystatin, however, promoted a significant reduction in the colonization of Candida spp. in the mucosa (p <0.005) and dental prostheses (p <0.005). The individuals who used the experimental mouthwash and spray reported pleasant taste and a small number of complaints related to it. Conclusion: The products containing C. zeylanicum EO promoted clinical efficacy, with a significant improvement of signs and symptoms, without significant reduction of CFU of Candida spp.

This work was aimed at the evaluation of the antifungal action of isolated and associated (+)-α-pinene and (+)-β-pinene enantiomers on Candida species, their possible mechanisms of action, their molecular interactions with enzymes related to wall formation and fungal cell membrane, as well as its antibiofilm activity. It was used 25 strains of Candida, of clinical origin and of reference, sensitive and resistant to licensed antifungal agents, for determination of Minimum Inhibitory Concentration (MIC), Minimum Fungicide Concentration (CFM), Fraction Inhibitory Concentration Index (ICIF), Microbial Time-kill Curve, possible mechanisms of action, molecular docking and the effect on the inhibition of the biofilm adherence provided by the enantiomers. A descriptive and inferential statistical analysis was performed, considering α=5%. The MIC values ranged from 114.06µM to 7300µM (15.6 µg/mL to 1000µg/mL) and from <57.03 µM to 1825 µM (<7.8 µg/mL to 250µg/mL) for (+)-α-pineno and (+)-β-pineno, respectively. After the association of the evaluated products, it was observed additivity (ICIF = 0.5) and indifference (ICIF = 1.125), when evaluated on strains of C. albicans and C. glabrata, respectively. It was observed that at the MIC and 2xMIC concentrations, (+)-β- pinene was able to reduce significantly (p≤0,05) the fungal growth after 8 hours of incubation. The MIC values of (+)-β-pinene increased 2x for the C. tropicalis and C. krusei strains, when in the presence of 0.8 M sorbitol. In the presence of ergosterol these values remained unchanged, suggesting that this substance acts by means of the inhibition of cell wall synthesis. In the evaluation of the molecular docking simulation, the binding energy values between (+)-β-pinene and enzymes, showed that Delta-14-sterol reductase presented a more stable interaction (−51 kcal/mol), suggesting a probable action on ergosterol biosynthesis. The (+)-β- pinene inhibited 67% of the multi-species biofilm. (+)-α-pinene and especially (+)- β-pinene present effect in vitro on strains of Candida, in planktonic state and organized into biofilms. The action of (+)-β-pinene is probably related to the binding of this molecule to enzymes involved with cell wall formation and ergosterol from fungi of the genus Candida.

The Candida genus usually has a commensal relationship in the oral cavity, modifying factors may alter this relationship directly or indirectly, making it pathogenic, triggering oral candidiasis. The phytotherapeutic products have been constituting a therapeutic alternative, widely used in the treatment of candidiasis. The objective of this study was to isolate and identify strains of Candida tropicalis and Candida parapsilosis from the oral cavity of healthy individuals through macro and micromorphology, physiological and biochemical tests. The in vitro and in silico sensitivity of these strains to eugenol and nystatin was then evaluated by determining the Minimum Inhibitory Concentration (MIC); Minimal Fungicide Concentration (MFC) and analyzing the mechanisms of action through microbial growth kinetics, micromorphology and association study (checkboard), and in silico assay. Eight strains of Candida tropicalis, one from the American Type Culture Collection - ATCC 13803 and seven from clinical origin and seven from Candida parapsilosis to their ATCC standard (22019) and six from clinical isolates were used. An antifungal activity of eugenol on the tested species was observed, a MIC and MFC of 64 μg / mL for Candida tropicalis was determined. The CFM / MIC ratio indicates fungicidal activity compared to 87.5% of the tested strains. In the Candida parapsilosis species the MIC was 256 μg / mL which coincided with the CFM in 100% of the strains tested. Regarding the association assay, strain ATCC 13803 and another clinic - LM-34 of C. tropicalis were used, the results showed antagonism of the substances analyzed for both the ATCC 22019 strain and the LM-34 clinical strain. Micromorphology demonstrated inhibition of virulence structures such as pseudohyphae and blastoconideas at the three concentrations analyzed for C. tropicalis (ATCC 13803 and LM-34) and C. parapsilosis (ATCC 22019 and LM-70) strains. The microbial death curve showed a fungicidal effect after 24 hours of experiment in both species studied. The results of the present study indicate a strong activity of the eugenol molecule on the strains of Candida tropicalis and Candida parapsilosis analyzed and could represent a therapeutic alternative for the treatment of oral candidiasis.

Oral candidiasis is a fungal infection caused by yeasts of the genus Candida, with C. albicans being the main pathogen. The emergence of resistant species against the available therapeutic arsenal as well as its adverse effects has driven new research on natural products. In view of this problem, the present study sought to investigate the antifungal activity of essential oil (OE) obtained from the leaves of Melissa officinalis L (lemon balm), isolated and associated with antifungal agents licensed on C. albicans strains. Two strains of the American Type Culture Collection (ATCC) and eight from the oral cavity (LM) were selected. The microdilution and sowing of subcultures were used to determine, respectively, the Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (CFM). The antifungigram was performed using the disc diffusion technique with the antifungal agents nystatin, amphotericin B, miconazole and fluconazole, evaluating them in isolation and associated with OE. MIC and MFC ranged from 64 to 128 μg/mL and 256 to 512 μg/mL, respectively. The presence of resistance of the strains to the antifungal agents nistatin (LM-38 and LM-65), amphotericin B (ATCC-76485, LM-3A, LM-38, LM-62 and LM -65) and fluconazole (LM-1A, LM- 1B, LM-38, LM-62 and LM-65). In the association tests, the results showed the influence of the essential oil on the antifungal activity, with synergism (S), indifference (I) and antagonism (A) being observed. The percentages found for each antifungal in the order (S, I and A) were: nystatin (30%, 30% , 40%), amphotericin B (30%, 50%, 20%), fluconazole (20% ,40% , 40%) and miconazole (100%, 0,0). In view of the above, it is concluded that the OO of M. Officinalis may become a promising product in the fight against oral candidiasis, since it has a strong antifungal activity against Candida albicans and that the use of this product associated with the licensed antifungal can, in some situations, potentiate its effectiveness of use in treatment.