The Oral Microbiota as Reservoir for Systemic Opportunistic Pathogens

Introduction The dental biofilm offers a protected environment for bacteria during systemic antibiotic treatment and may consequently be a source of reinfection. The concentration of antibiotic needed for inhibiting the growth of bacteria within a dental biofilm has been estimated to be 250 times greater than for planktonically growing bacteria (1). Chronic obstructive pulmonary disease (COPD) exacerbations cause pain and discomfort for the patient, healthcare resources and an increased usage of antibiotics. Smaller studies indicate that the act of advanced dental cleaning may lower the risk of reinfected COPD, but this needs to be validated in a larger randomized study to promote clinical implications.

COPD is a growing health problem worldwide. In 2020, COPD is projected to rank fifth in terms of burden of disease and third in terms of mortality (2). Assessment of COPD is based on the patient´s level of symptoms, exacerbation history and severity of spirometric abnormality. In a randomly selected Swedish cohort, the prevalence of COPD was 16.2%, and 34% of the COPD patients had never smoked (3). Unfortunately, none of the existing medications for COPD has been shown conclusively to modify the long-term decline in lung-function, but COPD patients are usually prescribed β2-adrenerg receptor agonists and anticholinergics (2). For acute exacerbations, the patients have oral steroids and antibiotics, typically doxycycline and amoxicillin. Importantly, two smaller (n=20 per group) pilot studies (4,5) have reported a lower frequency of exacerbations in COPD patients that have received advanced dental cleaning, suggesting that the oral microbiome might constitute a reservoir that infects the lungs in COPD. There is a need of studies based on larger cohorts in order to claim that dental treatment should be added to the treatment regime of COPD, to decrease the frequencies of exacerbations and thereby minimize physical suffering as well as related costs.

Hypothesis The hypothesis of this project is that adding advanced dental cleaning to established COPD treatment regime delays and lowers the frequency of exacerbations by eliminating a source of reinfections.

Aim The overall aim of this project is to investigate if the treatment of COPD can be optimized by adding advanced dental cleaning to the established treatment regime and thereby eliminate a source of reinfections.

The specific aim is to investigate if adding advanced dental cleaning to COPD treatment can (i) lower the number of exacerbations and (ii) improve the COPD symptoms the coming 6 and 12 months. In an effort to explain the underpinning mechanism we will collect oral dental biofilm samples at baseline and follow up in the treatment and control group to investigate changes in the composition of the biofilm.

COPD project At the lung clinic The COPD project will be conducted at Region Skane lung clinic and in collaboration with the COPD clinics in Skne In Örebro the subjects will be recruited from the lung clinic in collaboration with Dr. Josefin Sundh and the dental cleaning will be performed at the dental specialist clinic, folktandvarden Örebro. A COPD patient will be informed about the current study by a nurse. The patient will be asked to sign a consent and handed the written information including the number to the dental clinic.

At the dental clinic The dental clinic receives a phone call from the person who just signed a consent; alternatively, a nurse at the dental clinic calls the patient. At the dental clinic the patient is randomized to, either the advanced dental cleaning group, or a control group by the dentist or dental hygienist at the dental clinic. When the patient comes to the dental visit, both groups undergo a periodontal examination and microbiological sampling.

Questionnaire - Upon arriving at the dental clinic, the participant is asked to fill out a questionnaire that includes medical history and CAT-questionnaire.

The microbiological sampling is done by collecting the GenoTek tube by sampling the dental plaque samples.

Periodontal examination is performed on 6 sites per tooth including the third molar. Periodontal pockets ≥ 4mm are registered as well as bleeding upon probing, plaque index and attachment loss.

Intervention - The oral biofilm will be disrupted and removed on the sub- as well as supragingival surfaces of the teeth. Supragingival surfaces will be cleaned using the prophylactic paste RDA 250 supplemented with curettes and ultrasonic debridement. Subgingival surfaces will be cleaned using curettes and ultrasonic debridement when indicated based on the periodontal examination. The tongue will be cleaned using a tongue scraper. Finally, the patient will be asked to rinse 10 ml of 2 mg/ml chlorhexidine mouth rinse for one minute.

Follow-up - After 6 months, 12 months and 24 months the participants revisits the dental clinic. They fill out a new CAT form and a questionnaire asking how many exacerbations that needed medical attention since they joined the study (this is double checked in their medical records), if they have taken antibiotics for any other reason or changed their medications in any way. They are also asked about any dental treatments.

Microbiological analysis The subsequent microbiological analysis will be executed using deep sequencing, as well as qPCR.

Time schedule 2016-2017 - Participants are recruited, randomized and the treatment group is treated. 2017-2020 - Participants are followed up.

2020 - Data analysis and publication.

Network Daniel Jönsson - PhD in 2007 and a postdoc on the systemic effects of periodontal disease in 2009 and 2010 at Columbia University, New York, NY, USA. Became a specialist in periodontics in 2014 and currently positioned at Malmö University and Region Skane, Lund. Dr. Jönsson will start a part time position in Örebro in 2016.

Bodil Ohlsson - Professor and specialist in Internal Medicine and Gastroenterology at Lund University and Region Skane University hospital.

Hanan Tanash - PhD and specialist in Internal Medicine. Field of interest - COPD.

Josefin Sundh - Associate Professor at Örebro University hospital. Field of interest - COPD.

Frida Fak - Associate Professor at Lund University. Field of interest - microbiology.

Folktandvarden Skane - two dental hygienists have been recruited for the project.

Folktandvarden Örebro - a post-graduate student is being recruited for the dental cleaning as well as managing the logistics of the project. Daniel Jönsson will be the supervisor of the student.

Power analysis In a power analysis based on the standard deviations from the pilot study of Kucukoskun et al. [3] indicated 80% power to detect a difference of p\<0.05 of 1.5 exacerbations per year in a sample of 49 subjects in each group.

Significance As antibiotics is part of the COPD treatment regime this study may restrict the usage of antibiotics, minimizing antibiotic resistance. COPD exacerbations disable the person to go to work which causes financial consequences, but also healthcare expenses. Most importantly, the study will plausibly improve life quality and extend the life span of patients suffering from COPD. We already have preliminary data that subjects in the treatment group have an OR 3.9 for being stable or having less COPD-symptoms in this progressive disease.