This publication is protected and can be accessed only from certain IPs.
This publication is protected and can be accessed only from certain IPs.

Title: Oral microbiota in systemic diseases


Introduction The oral microbiota is the second most diverse and dynamic microbial ecosystem in the human body. It plays essential role in maintaining human health [27]. On the one hand, the imbalance of the oral microbiota (referred to as dysbiosis) may play a significant role in the pathogenesis of local and systemic disorders. On the other hand, such disorders can also affect the oral micriobiota. This work presents the assessment of the oral microbiota in two different disease states - in patients treated in the Intensive Care Unit (ICU) due to SARS-CoV-2 infection and in patients with type 1 diabetes (DM I). Potential interactions between the SARS-CoV-2 virus and the human oral microbiota are not sufficiently understood [15, 16]. Patients with COVID-19 requiring mechanical ventilation in an intensive care unit (ICU) are at high risk of developing severe systemic complications, including ventilator-associated pneumonia, this maks its important to maintain and monitor oral health. Type 1 diabetes is a disease with different etiopathogenesis, clinical course, treatment and complications. Continuous subcutaneous insulin infusion (CSII) with personal insulin pump (IP) is a modern method of insulin administration, with evidence for its superiority to traditional multiple daily injections in metabolic control. A bidirectional relationship between or ; al health and DM I has been reported as a predisposing factor to oral infections, which in turn exacerbates the progression of systemic diseases. To date, no attempts have been made to characterize the microbiota of particular niches in the oral cavity in DM I patients. Objectives of the work 1. Assessment of the oral microbiota in two different systemic disease states, that is in patients with COVID-19 hospitalized in an intensive care unit and patients with type 1 diabetes treated with CSII. 2. The determination of optimal sites of oral microbiota sampling concerning bacterio- and mycobiota and characterisation of the biodiversity of the identified niches. Material and methods In the first part of the study, 56 adult COVID-19 patients qualified for mechanical ventilation in a Temporary ICU due to pneumonia. Patients oral health assessed using a modified Beck Oral Assessment Score (BOAS) [30] . Four oral habitats were sampled: the buccal mucosa, the tongue, buccal dental surface and gingival cervical fluid (GCF). The samples were cultured with the use of traditional methods for aerobic and anaerobic bacteria and fungi. After isolation, the microorganisms were identified by MALDI-TOF MS (Vitek MS Home bioMérieux). The second part of the study conducted in 23 adult patients with DM I, aged 18- 35 years old, treated with IP. The general condition of the ; oral cavity was assessed using the Oral Health Assessment Tool (OHAT) [31]. Six oral habitats were sampled: buccal (marked A) and soft palate (B) mucosa, the tongue (site marked C), palatal (Da) and buccal (Db) dental surface, and the gingival pocket (E). Material from sites A, B and C was collected using ESwab™, from site D with Tooth Cleanic KerrHawe, and from site E with PerioPaper Strips. The samples were cultured with the use of traditional methods for aerobic and anaerobic bacteria and funghi. After isolation, the microorganisms were identified by MALDI-TOF MS (Vitek MS Home bioMérieux). Results summary and conclusions Analysis of material from COVID-19 patients revealed significant qualitative and quantitative dysbiosis in the oral microbiota. The dysbiosis involved decreased species diversity and abundance of pathogenic strains of Acinetobacter baumannii, Enterococcus faecalis, Escherichia coli and Klebsiella pneumoniae, comprising noteworthy findings among this group of patients. Moderate or severe disorders of oral health (BOAS score 10-14) was correlated with the increased level of dysbiosis. The median CFU counts of all bacterial strains in buccal dental surface was 4.0E+5 (1.0E+5 –1.4E+6) and in gingival crevicular fluid 2.0E+5 (4.0E+4 – 8.0E+5). The highest median CFU counts were observed for Enterococcus spp. and Lactobacillus spp. Durin ; g the the first part of the study, a very rare case of invasive pulmonary aspergillosis (IPA) caused by A. niger from in the oral cavity of a mechanically ventilated COVID-19 patient was identified. A. niger was detected in the gingival pocket was diagnosed earlier than in the bronchial lavage fluid.. Analysis of patients with DMI showed that they had good metabolic control of diabetes (mean HbA1c% 6,97 ± 0,95%). The oral health status in this group of patients was good as indicated by the OHAT scores. The oral microbiota in this group of patients was diverse across all investigated sampling sites and characteristics of each niche with detailed information on all identified bacteria and fungi species were presented. In this doctoral thesis a bidirectional relationship between the oral health status and oral microbiota with systemic diseases was demonstrated. The acquired results suggest, that in patients with a severe course of COVID-19 who are hospitalized in an ICU, improper oral hygiene leading to poor oral health status and mechanical ventilation, can facilitate the passage of microorganisms from the oral cavity to lower respiratory tract, leading to pneumonia. Ensuring effective oral hygiene is crucial in sustaining the balance of oral bacterio- and mycobiota in patients with severe COVID-19. The results of oral microbiota analysis can suppl ; ement the diagnostic process, being a predictor of the subsequent exacerbation of inflammation and the emergence of IPA. The analysis of microbiota from distinct oral niches in patients with DM I treated with CSII and with good metabolic control of diabetes showed that the oral cavity cannot be treated as one homogenous microbial ecosystem. Three different and optimal sampling sites for the assessment of the oral microbiota were identified. The results of the presented analysis may be the basis for further studies of large groups of patients with DM I.

Place of publishing:


Level of degree:

2 - studia doktoranckie

Degree grantor:

Rada Dyscypliny Nauki medyczne


Gregorczyk-Maga, Iwona

Date issued:




Call number:



pol; eng

Access rights:

tylko w bibliotece

Object collections:

Last modified:

Jun 5, 2024

In our library since:

Apr 12, 2024

Number of object content hits:


Number of object content views in PDF format


All available object's versions:


Show description in RDF format:


Show description in OAI-PMH format:


Edition name Date
ZB-140223 Jun 5, 2024


Citation style:

This page uses 'cookies'. More information