key: cord-0707073-gmt0t745
authors: Morimoto, Susana; Rosin, João Luiz Azevedo; Matuck, Bruno Fernandes; Schröter, Gabriella; Rodrigues, Maria Fernanda Setúbal Destro; Ramalho, Karen M.; Raggio, Daniela Procida; Moreira, Maria Stella; da Silva, Luiz Fernando Ferraz
title: aPDT for oral decontamination of hospitalized patients with COVID 19
date: 2022-02-16
journal: Photodiagnosis Photodyn Ther
DOI: 10.1016/j.pdpdt.2022.102762
sha: 2cc14db38f5962ca39934ff7fc947040901bd3a7
doc_id: 707073
cord_uid: gmt0t745

Emerging variants of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) may have an impact on the virus's transmissibility and pathogenicity and an increased risk of reinfection. Antimicrobial photodynamic therapy (aPDT) is a promising technique to decontaminate the oral cavity to minimize and inactivate microorganisms' load. This article reports through a case series, a proposal for efficient oral decontamination for hospitalized patients with COVID 19 using aPDT. Samples of oral tissues were obtained after aPDT and analyzed using two methods of RT‐qPCR to elucidate qualitative and quantitative viral profiles of SARS-CoV-2 RNA in the oral cavity. There was a reduction of viral load in the oral cavity immediately or one hour after the use of aPDT. This method could be a good option to decontaminate the oral cavity to minimize and inactivate microorganism load.

Emerging severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) variants may have an impact on the virus's transmissibility and pathogenicity and an increased risk of reinfection. Antimicrobial photodynamic therapy (aPDT) is a promising technique to decontaminate the oral cavity to minimize and inactivate microorganisms' load. This article reports through a case series, a proposal for efficient oral decontamination for hospitalized patients with COVID 19 using aPDT. Samples of oral tissues were obtained after aPDT and analyzed using two methods of RT-qPCR to elucidate qualitative and quantitative viral profiles of SARS-CoV-2 RNA in the oral cavity. There was a reduction of viral load in the oral cavity immediately or one hour after the use of aPDT. This method could be a good option to decontaminate the oral cavity to minimize and inactivate microorganism load.

Background SARS-CoV-2 has already been detected in several organs and tissues, including oral tissues and saliva. The role of saliva in disease spread may be associated with viral replication within salivary gland cells that are reservoirs for SARS-CoV-2 [1] In addition, patients with COVID-19 may undergo long periods of hospitalization and often need oral care. In intensive care units, oral decontamination needs to be effective to prevent oral bacteremia, viremia, and co-infections. The association of oral bacteremia and viremia with systemic manifestations has been reported in a patient with heart disease and COVID-19 [2] . The clinical management of these patients represents a great challenge for healthcare workers, especially when treatments involve exposure to saliva and/or blood. A fact that places them at greater risk of contamination and virus transmission [3] .

Photodynamic therapy (aPDT) is an effective alternative method for decontamination of the oral cavity, as it forms reactive oxygen species that can inactivate enveloped and non-envelope DNA and RNA viruses, which suggest their promising potential against SARS-Cov-2 [4] in reducing the risk of contamination for dentists and patients.

In vitro studies confirmed the effectiveness of aPDT antiviral activity against SARS-CoV-2 [4] , but no in vivo study was conducted with aPDT and SARS-CoV-2. This article reports through a case series, a proposal for efficient oral decontamination for hospitalized patients with COVID 19 using aPDT. The oral cavity of both patients was rinsed with 10 ml of curcumin final solution for the 30s, and cotton rolls wet with the solution were placed in the upper left superior region for 5 min (Fig 1A) . The buccal and gingival surface were irradiated with a blue LED (ECEL ® , RD-7, 455 + 30nm, 900mW/cm 2 ) with a cylindrical diffuser tip, (89 mm in length and 6.73 mm in diameter) for 5 minutes (Poly Wireless, Kavo-Brazil) (Fig 1B) . The buccal and gingival mucosa surface of the left posterior region were scraped with a sterile punch (Kolplast ci LTDA, Brazil) three times (before therapy, immediately after, and 1 hour after aPDT).

The samples were frozen and stored at -80°C (Fig 1C-D) . RT qPCR reactions were performed as previously described [1] 

aPDT has emerged as a promising technique to reduce antimicrobialresistant pathogens [4] . Our study showed that patients had lower levels of SARS-CoV-2 genes immediately or 1h after a single section of aPDT compared to baseline viral load, deep layers could be achieved. Furthermore, no adverse effects were reported until 48h after the procedure.

Antimicrobial PDT with methylene blue has been used in different procedures, however, in oral disinfection curcumin has been investigated and presented promising results. It has the advantage of being a colorless natural substance, combined with a LED light, safe for the oral tissues, has low cost, and can promote the reduction of microorganisms in a similar way to traditional 1minute mouthwash with 0,12% chlorhexidine [7, 8] . The main targets of the curcumin are external structures of the microorganisms, the adhesion of the photosensitizer is sufficient for its destruction when activated by light. aPDT also has a crucial role in the minimal risk of resistance development, which provides an advantage over the mutation ability of SARS-CoV-2 [4] and conventional antimicrobials [7] .

COVID-19 determined paradigm shifts for healthcare workers, whose repercussions have not yet been dimensioned. aPDT is a promising technique for clinical use in the pandemic era, but further clinical trials must establish a viable, effective, and safe oral decontamination protocol for patients infected with SARS-CoV-2.

Salivary glands are a target for SARS-CoV-2: a source for saliva contamination

Bilateral paresthesia associated with cardiovascular disease and COVID-19

Risk of COVID-19 in healthcare workers working in intensive care setting

How can biophotonics help dentistry to avoid or minimize cross infection by SARS-CoV-2?

Effects of photodynamic therapy with blue light and curcumin as mouth rinse for oral disinfection: a randomized controlled trial

Cycle threshold values in RT-PCR to determine dynamics of SARS-CoV-2 viral load: An approach to reduce the isolation period for COVID-19 patients

Overall-mouth disinfection by photodynamic therapy using curcumin

Potential of curcumin-mediated photodynamic inactivation to reduce oral colonization. Photodiagnosis Photodyn Ther