OBJECTIVE: The present study aimed to evaluate the presence of SARS-CoV-2 in the subgingival biofilm of patients with COVID-19 and to correlate SARS-CoV-2 with periodontal inflammation.
METHODS: In this cross-sectional study, subgingival biofilm was collected from 28 healthy individuals and 67 individuals diagnosed with COVID-19. They were categorized into periodontal health [absence of bleeding on probing (BoP) and clinical attachment loss (CAL); n = 48]; gingivitis [BoP + probing depth (PD) < 4mm + absence of CAL; n = 37); or periodontitis (PD ≥ 5mm + CAL; n = 10). One pool of dental biofilm was obtained for each individual (shallow subgingival) independently of periodontal state, in periodontitis cases, another sample was collected from the deepest site. All samples were tested for the presence of SARS-CoV-2 RNA using the qRT-PCR technique. Chi-square analysis and t-test were applied to evaluate associations between the presence of SARS-CoV-2 RNA and its quantification and periodontal diagnosis (p≤0.05).
RESULTS: SARS-CoV-2 RNA was detected in subgingival biofilm of 35.8% (n=24) of individuals with COVID-19; whereas there was no detection in individuals without COVID-19. SARS-CoV-2 was detected in 27.9% (n=12) of participants with periodontal health, 50% (n=12) with gingivitis, and none with periodontitis. It was not possible to detect any association between periodontal diagnosis and SARS-CoV-2 RNA presence (p ≥ 0.09 or quantification (p ≥ 0.31).
CONCLUSION: SARS-CoV-2 RNA was detected in the shallow subgingival biofilm, but not in the subgingival biofilm of deep periodontal pockets of patients with COVID-19. The present findings confirm the presence of SARS-CoV-2 in subgingival biofilm, independently of periodontal status. Anywise, this highlights the critical need to unravel the virus interaction with local microbiota.
OBJECTIVE: The present study aimed to describe and compare subgingival biofilm profile of COVID-19 patients in the presence or absence of SARS-CoV-2 in this biofilm, in periodontal health and gingivitis condition.
MATERIAL AND METHODS: In this cross-sectional study, subgingival biofilm collections were carried out on symptomatic individuals diagnosed with COVID-19 and on healthy individuals, covering 60 patients. Clinical data was collected and periodontal examination was performed. Subgingival biofilm samples from all individuals included in the study were tested for the presence of SARS-CoV-2 using the qRT-PCR technique. Individuals were grouped according to combinations of presence or absence of COVID-19, presence or absence of SARS-CoV-2 in subgingival biofilm, and presence or absence of gingivitis. The biofilm samples were sequenced for the 16S gene, regions V3-V4. Species were evaluated when they were present in at least 10% of the samples with a minimum count of 10 readings. Logistic models were applied to assess profile associations between certain groups (p≤0.05).
RESULTS: 11 phyla, 93 genera and 258 species were detected. Differences in α-diversity and β-diversity were found, with notorious upper-regulation in richness in COVID-19 groups and down-regulation in diversity in the presence of gingivitis and COVID-19; while the local presence of SARS-CoV-2 did not generate expressive impacts. The presence of COVID-19 in association with gingivitis showed the most expressive results, with emphasis on the increase of bacteria from genera Saccharibacteria (p≤0.04) and Streptococcus (p≤0.01). The genera Saccharibacteria was also dominant in periodontal health, in association with an increase of periodontopathic bacteria (including Parvimonas micra and Prevotella intermedia).
CONCLUSION: COVID-19 was related to changes in subgingival biofilm microbiota, independently of detecting SARS-CoV-2 in the local ecosystem. The genera Saccharibacteria and Streptococcus were repeatedly found and demands attention. COVID-19 patients should emphasize oral hygiene to reduce the risk of local dysbiosis and its consequences.
