key: cord-1054019-xk6zg17u
authors: Sampson, V.
title: Oral hygiene risk factor
date: 2020-04-24
journal: Br Dent J
DOI: 10.1038/s41415-020-1545-3
sha: 361b49f380279f4abd1fa1e3c6da7e467fb5bee4
doc_id: 1054019
cord_uid: xk6zg17u

nan

Sir, I would like to inform readers about the potential connection between high bacterial load in the mouth and complications associated with COVID-19 infection.

Oral hygiene should be improved during a COVID-19 infection in order to reduce the bacterial load in the mouth and the risk of a bacterial superinfection. We recommend that poor oral hygiene be considered a risk to COVID-19 complications, particularly in patients predisposed to altered biofilms due to diabetes, hypertension or cardiovascular disease. Bacteria present in patients with severe COVID-19 are associated with the oral cavity, and improved oral hygiene may reduce the risk of complications. Whilst COVID-19 has a viral origin, it is suspected that in severe forms of the infection, bacteria plays a part, increasing the chance of complications such as pneumonia, acute respiratory distress syndrome, sepsis, septic shock and death. 1 The development and severity of complications following a COVID-19 infection depend on numerous host and viral factors that will affect a patient's immune response. Whilst 80% of patients with COVID-19 infections have mild symptoms, 20% progress to have a severe form of infection associated with higher levels of inflammatory markers (Interleukin 2, 6, 10) and bacteria. 2,3 They also exhibit a remarkably higher neutrophil count and lower lymphocyte count than in mild patients. 4 A high neutrophil count is abnormal for a viral infection, but common for a bacterial infection, suggesting that in severe cases of COVID-19, bacterial superinfection is common.

The three main comorbidities associated with an increased risk of complications from COVID-19 are diabetes, hypertension and cardiovascular disease. 5 These comorbidities are also associated with altered oral biofilms and periodontal disease. Periodontopathic bacteria are implicated in systemic inflammation, bacteraemia, and pneumonia.⁶ Bacteria present in the metagenome of patients severely infected with COVID-19 included high reads for Prevotella, Staphylococcus, and Fusobacterium, all usually commensal organisms of the mouth.⁷ Over 80% of patients in ICU exhibited an exceptionally high bacterial load,³ and treatment has been successful with a dual regime of an antiviral and an antibiotic.⁸ It is clear that bacterial superinfections are common in patients suffering from a severe case of COVID-19.

V. Sampson, London, UK

Available at: https:// www.who.int/publications-detail/clinical-management-ofsevere-acute-respiratory-infection-when-novel-coronavirus-(ncov)-infection-is-suspected

Correlation Analysis Between Disease Severity and Inflammation-related Parameters in Patients with COVID-19 Pneumonia. Tongji Hospital

Neutrophil-to-Lymphocyte Ratio Predicts Severe Illness Patients with 2019 Novel Coronavirus. Beijing Ditan Hospital

Functional exhaustion of antiviral lymphocytes in COVID-19 patients

Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: A retrospective cohort study

Prevotella intermedia induces severe bacteremic pneumococcal pneumonia in mice with upregulated platelet-activating factor receptor expression

Metagenome of SARS-Cov2 patients in Shenzhen with travel to Wuhan: OSF Preprints

Hydroxychloroquine and azithromycin as a treatment of COVID-19: Results of an Open-Label Non-randomized trial

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