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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 log 10 UFC/ I 2 =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., Competing Interests: Declaration of Competing Interest None., (Copyright © 2022. Published by Elsevier B.V.)

This investigation assessed the effect of five consecutive daily topical treatments of antimicrobial photodynamic therapy (aPDT), nystatin (NYS), and an association of treatments on a fluconazole-resistant strain of Candida albicans colonizing the tongues of mice. After the last treatments application, colonies of C. albicans were recovered from the tongues and used to determine their fluconazole susceptibility. After 24 hours of the last treatment, the mice tongues were processed to evaluate the expression of C. albicans genes related to the virulence and ergosterol production. The fluconazole susceptibility test yielded a resistance profile similar for all treatment groups and the control group (no treatment). The treatments aPDT, NYS, NYS+aPDT, and aPDT+NYS promoted a reduction in ALS1, EFG1, CAP1, SOD1, SAP1, and LIP3 expression. The expression of HWP1 was higher in the three groups containing nystatin. In contrast, the treatments produced a significative increase in CAT1 gene expression, mainly in the groups in which aPDT was performed. The expression of genes related to ergosterol production was significantly reduced by the treatments evaluated (aPDT, NYS, NYS+aPDT, and aPDT+NYS). Thus, the consecutive topical treatments performed on mice tongues promoted a reduction in the expression of virulence and ergosterol biosynthesis genes of a fluconazole-resistant C. albicans., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Antimicrobial Photodynamic Therapy (aPDT) was introduced as a therapy due to resistance that microorganisms have developed to conventional drugs. The study aimed to evaluate the potential of successive applications of aPDT in effecting Candida albicans susceptibility and also whether the presence of fluconazole effected the recovery of the fungi in the culture medium. Planktonic cultures and biofilm were subjected to successive applications of Photodithazine-mediated (25 mg/L) LED-associated aPDT (660 nm, 34 mW/cm 2 ). Plating was performed on Sabouraud Dextrose Agar supplemented or not with fluconazole to recover colony-forming units per milliliter (CFU/mL). Surviving cells were recovered, recultivated, and again exposed to the treatment. The treatments were performed until not enough colonies were available for recultivation and continuation of the protocol. The complete inactivation of the fungus was obtained after three and five applications for planktonic culture and biofilm, respectively. A reduction of 6.3 log 10 was observed after third applications in the planktonic cultures grown on medium without fluconazole, while there was a 7 log 10 reduction of these cultures grown on fluconazole medium. However, a reduction of 6.1 log 10 occurred for biofilms after fifth applications for cultures grown on medium without fluconazole, while a reduction of 6.7 log 10 was observed for cultures grown on medium with the antifungal. Thus, aPDT was potentiated by fluconazole. C. albicans in planktonic and biofilm cultures are susceptible to successive applications of PDZ-mediated aPDT, and tolerance to aPDT is higher in the biofilm., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Staphylococcus aureus have a great ability to become rapidly resistant to conventional antimicrobial therapies. This study evaluated the efficacy of antimicrobial photodynamic therapy (aPDT) mediated by Curcumin (Cur) and light-emitting diode (LED) in the inactivation of biofilms of methicillin susceptible and resistant S. aureus (MSSA and MRSA, respectively)., Methods: Biofilms were treated with Cur (20, 40 or 80 μM) and illuminated with LED source (455 ± 3 nm; 5.28 J/cm 2 ) (aPDT groups), or treated either with Cur or LED only. Other samples were not exposed to Cur or LED (negative control). The biofilms viability after all experimental conditions were evaluated by counting the number of colonies (CFU/mL) and XTT assay. Additional samples were also evaluated by LIVE/DEAD® staining using confocal laser scanning microscopy (CLSM). Data were analyzed by ANOVAs followed by the Games-Howell post hoc test (α = 0.05)., Results: For both strains, all aPDT groups significantly reduced both CFU/mL and metabolic activity of biofilms compared to the negative control (p < 0.001). The results were enhanced when 80 μM of Cur was used. CLSM images showed that both bacteria biofilms submitted to aPDT had a large number of red-stained colonies, especially at aPDT80. In general, MRSA biofilms tended to be less susceptible to aPDT than MSSA biofilms., Conclusions: It can be concluded that aPDT mediated by Cur and LED was an efficient method to inactivate 48 -h biofilms of both S. aureus strains., Competing Interests: Declarations of interest All authors declare that they have no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)