Background: Up to 48% of ventilated coronavirus disease 2019 (COVID-19) patients develop ventilator-associated pneumonia (VAP) during hospitalization in an ICU. Dysbiotic oral microbiota can colonize the lower respiratory tract and lead to VAP. It is recommended to introduce oral care strategies in the ICU to prevent VAP. In this study, we observed the impact of an oral hygienic protocol with tooth brushing on cultivable oral bacteriota, the incidence of HAI and patient safety among mechanically ventilated COVID-19 patients in an ICU setting. Methods: In this prospective cohort study, we recruited 56 adult COVID-19 patients who qualified for mechanical ventilation. Patients were divided into 2 groups depending on the oral care procedure: standard and extended oral procedures with tooth brushing. Oral bacteriota samples were taken first within 36 h and after 7 days of intubation. Microorganisms were identified by MALDI/TOF mass spectrometry. bacterial health care-associated infection (HAI) cases were retrospectively analyzed by etiology. A PFGE study was performed for Klebsiella pneumoniae to check for clonal spreading of strains from oral bacteriota samples and HAI cases. Results: We observed significant dysbiosis and a decrease in cultivable oral bacteriota diversity, with a high frequency of potentially pathogenic species, including Acinetobacter baumannii and K. pneumoniae. The HAI incidence rate was high (55.2/1000 patient-days), most commonly of K. pneumoniae and A. baumannii etiologies, which correlated with the presence of A. baumannii and K. pneumoniae in the oral samples. Strains isolated from VAP cases were the same as oral isolates in 8 cases. The procedure with tooth brushing led to less frequent identification of A. baumannii in oral samples (55.6% vs. 5.3%, p = 0.001); however, it did not decrease the incidence of HAIs. Conclusions: Dysbiotic oral bacteriota is an important source of respiratory pathogens. The introduction of tooth brushing in oral hygiene protocols in an ICU setting was effective in decreasing the extent of oral bacteriota dysbiosis; however, it did not reduce the risk of HAIs or mortality. Trial registration: 1072.6120.333.2020.

Objective: The oral microbiota is a very complex and dynamic microbial ecosystem. Alterations of its balance can result in oral and systemic diseases. We aimed to characterize the microbiota in particular niches of the oral cavity in adult type 1 diabetes patients treated with continuous infusion of insulin with insulin pump (IP). In addition, we aimed to determine optimal sites of oral microbiota sampling in studies of large research groups of patients with DM I. Design: In this pilot study, we sampled the buccal and soft palate mucosa, tongue, palatal and buccal dental surfaces and gingival pockets of adult DM I patients treated with IP. Results: In total, 23 patients were recruited. The oral microbiota was dominated by Streptococus and Neisseria, with a low incidence of cariogenic S. mutans and Lactobacillus, as well as periodontal pathogens such as Prevotella. There were significant differences in overall CFU counts of all strains, Gram-positive, Staphylococci, Streptococci and S. oralis strains between mucosal and dental surface sites. The overall CFU counts of all strains and Gram-positive strains were higher in dental sites vs. mucosal sites (both p < 0.001). CFU counts of S. oralis were significantly higher in dental sites vs. gingival pocket sites (p = 0.013). Candida species were rare. The mucosal sites on the buccae presented lower diversity and bacterial counts. Conclusions: In the study group of adult DM I patients treated with IP, the microbiota in particular niches of the oral cavity was significantly different. Three distinct and optimally appropriate sampling sites for oral microflora were identified: buccal and palatal mucosa, dental surface and gingival pockets. The results of this study may be the basis for further studies of large groups of patients with DM I.

Potential interactions between the SARS-CoV-2 virus and the human oral microbiota are currently investigated widely. Patients with COVID-19 requiring mechanical ventilation in an intensive care unit (ICU) setting are at high risk of developing severe complications, including ventilator-associated pneumonia, thus making oral health management important. The aim of this study was to evaluate the oral health status and assess the dysbiosis of cultivable oral bacteriota in COVID-19 patients hospitalized in an ICU with acute respiratory distress within 36 h following intubation. In this prospective cohort study, we recruited 56 adult COVID-19 patients that qualified for mechanical ventilation in the Temporary ICU for COVID-19 Patients of the University Hospital in Krakow. On admission to the ICU, oral health of patients was assessed using the modified Beck Oral Assessment Score (BOAS). Four oral habitats were sampled, namely the buccal mucosa, tongue, buccal dental surface and gingival pocket. Microorganisms were identified by MALDI/TOF mass spectrometry. The mean age of the study population was 66.5 ± 12.7 years, there were 24 (42.9%) females. All patients included in this study were intubated and ventilated in the ICU, with a corresponding high mortality rate (76.8%). On admission to ICU, 76.8% subjects scored 11–20 on the BOAS scale (median 12 [IQR 10–14]), indicating moderate or severe dysfunction of oral health. Potentially pathogenic bacteria were identified in the oral microbiota samples, including Acinetobacter baumannii, Enterococcus faecalis, Escherichia coli and Klebsiella pneumoniae in 23.2%, 39.3%, 17.9%, and 19.6% of patients, respectively. Lactobacillus spp. were present in 57.1% subjects. The mean CFU counts of all bacteria strains in dental brushes were 9.3E+5 (1.4E+6) and in gingival pockets 7.6E+5 (1.4E+6). The highest CFU counts were observed for Enterococcus spp. and, Lactobacillus spp., although these did not differ significantly from CFU counts of Streptococcus spp. and Staphylococcus spp. In this report we comprehensively characterized the oral health condition and cultivable oral bacteriota in COVID-19 patients hospitalized in an ICU with acute respiratory distress within 36 h following intubation. The oral bacteriota showed significant qualitative and quantitative dysbiosis. Hospitalization in an ICU and mechanical ventilation are important factors leading to oral dysbiosis in SARS-CoV-2 patients.

Background. Diabetes is a risk factor for a severe course of COVID-19. We evaluated the characteristics and risk factors associated with undesirable outcomes in diabetic patients (DPs) hospitalized due to COVID-19. Materials and Methods. The data analysis of patients admitted between March 6, 2020, and May 31, 2021, to the University Hospital in Krakow (Poland), a reference center for COVID-19, was performed. The data were gathered from their medical records. Results. A total number of 5191 patients were included, of which 2348 (45.2%) were women. The patients were at the median age of 64 (IQR: 51–74) years, and 1364 (26.3%) were DPs. DPs, compared to nondiabetics, were older (median age: 70 years, IQR: 62–77 vs. 62, IQR: 47–72, and < 0.001) and had a similar gender distribution. The DP group had a higher mortality rate (26.2% vs. 15.7%, < 0.001) and longer hospital stays (median: 15 days, IQR: 10–24 vs. 13, IQR: 9–20, and < 0.001). DPs were admitted to the ICU more frequently (15.7% vs. 11.0%, < 0.001) and required mechanical ventilation more often (15.5% vs. 11.3%, < 0.001). In a multivariate logistic regression, factors associated with a higher risk of death were age >65 years, glycaemia >10 mmol/L, CRP and D-dimer level, prehospital insulin and loop diuretic use, presence of heart failure, and chronic kidney disease. Factors contributing to lower mortality were in-hospital use of statin, thiazide diuretic, and calcium channel blocker. Conclusion. In this large COVID-19 cohort, DPs constituted more than a quarter of hospitalized patients. The risk of death and other outcomes compared to nondiabetics was higher in this group. We identified a number of clinical, laboratory, and therapeutic variables associated with the risk of hospital death in DPs.

Critically ill COVID-19 patients requiring mechanical ventilation in the intensive care unit are at risk of developing invasive candidiasis. In this study we aimed to (1) characterize oral cultivable mycobiota of mechanically ventilated adult COVID-19 patients in an ICU setting by sampling four distinct oral niches in two fixed time points with regards to oral health status, (2) investigate Candida spp. infections in this population, and (3) compare oral mycobiota with selected bacteriobiota strains during the observation in the ICU. We recruited 56 adult COVID-19 patients who qualified for mechanical ventilation. Patients received either standard or extended oral care procedures with tooth brushing. Oral samples were taken first within 36 h and after 7 days of intubation. Yeast-like fungi were identified by MALDI/TOF mass spectrometry. Yeast infection cases were retrospectively analyzed. Candida spp. in oral sampling was identified in 80.4% and 75.7%, C. albicans in 57.1% and 61.1%, and non-albicans Candida species in 48.2% and 47.2% patients at baseline and follow-up, respectively. There were no differences in the overall CFU counts of Candida spp. species and individual Candida species in oral samples, both at baseline and follow-up. At baseline, a higher prevalence of Candida spp. was associated with a higher identification rate of Lactobacillus spp. (64.4% vs. 27.3%, p = 0.041). At follow-up, there was a borderline lower prevalence of Candida spp. in patients with Lactobacillus spp. identified (57.1% vs. 87.0%, p = 0.057). The incidence rate of candidiasis was 5.4% and the incidence density was 3.1/1000 pds. In conclusion, non-albicans Candida species in oral samples were identified in nearly half of patients. Oral health was moderately impaired. A high incidence of yeast infections, including invasive cases, in patients hospitalized in the ICU due to COVID-19 and requiring mechanical ventilation was noted. Severe COVID-19 and disease-specific interventions within the ICU possibly played a major role promoting Candida spp. infections.

People with type 1 diabetes (PwT1D) are at higher risk of developing periodontal diseases. We investigated the impact of dietary habits on the gingival crevicular fluid (GCF) microbiome and metabolome in PwT1D. The oral and periodontal examination was performed and GCF sampled. Genomic DNA was extracted, bacterial 16S rRNA sequenced and concentrations of short-chain fatty acids and trimethylamine derivatives determined. Pro-healthy (pHDI) and non-healthy diet indices (nHDI) were calculated using the validated Questionnaire of Eating Behaviours. In total, 110 participants were included (mean age 27.1 ± 6.0 years, 60.0% male). In 65 PwT1D, the mean duration of diabetes was 15.5 ± 8.4 years and mean Hba1c% 6.97 ± 0.95% (53 ± 2.2 mmol/mmol). 22 cases of mild gingivitis (G) were identified, all in the T1D group. There were no significant differences in the frequencies of pHDI categories between study groups (T1D with G, low 19 [86.4%] and moderate 3 [13.6%]; T1D without G, low 28 [66.7%] and moderate 14 [45.2%]; control, low 30 [68.2%], moderate 14 [31.8%]; p = 0.213). GCF microbiome composition did not differ between pHDI categories. In PwT1D and G caproic acid was higher in low vs. moderate pHDI category (3.5 [0.9–4.9] vs. 0.64 [0.49-NA] umol/l, p = 0.04). In people with T1D without G, isocaproic acid and glycerophosphorylcholine were lower in low vs. moderate pHDI category (0.14 [0.13–0.46] vs. 0.45 [0.18–1.24] umol/l, p = 0.032, and 71.23 [32.83–120.40] vs. 129.8 [70.5–228.1] ng/ml, p = 0.013). This was the first study to report on the impact of diet on GCF in PwT1D. The state of periodontal tissues was worse in people with T1D, overweight and with a worse quality diet. Alterations in the concentrations of selected GCF metabolites suggest an indirect association between the quality of diet and contents of pro-healthy and non-healthy products on the state of periodontium.