Nitrate and the origin of saliva influence composition and short chain fatty acid production of oral microcosms

Nitrate is emerging as a possible health benefactor. Especially the microbial conversion of nitrate to nitrite in the oral cavity and the subsequent conversion to nitric oxide in the stomach are of interest in this regard. Yet, how nitrate influences the composition and biochemistry of the oral ecosystem is not fully understood. To investigate the effect of nitrate on oral ecology, we performed a 4-week experiment using the multiplaque artificial mouth (MAM) biofilm model. This model was inoculated with stimulated saliva of two healthy donors. Half of the microcosms (n = 4) received a constant supply of nitrate, while the other half functioned as control (n = 4). Additionally, all microcosms received a nitrate and sucrose pulse, each week, on separate days to measure nitrate reduction and acid formation. The bacterial composition of the microcosms was determined by 16S rDNA sequencing. The origin of the saliva (i.e., donor) showed to be the strongest determinant for the development of the microcosms. The supplementation of nitrate was related to a relatively high abundance of Neisseria in the microcosms of both donors, while Veillonella was highly abundant in the nitrate-supplemented microcosms of only one of the donors. The lactate concentration after sucrose addition was similarly high in all microcosms, irrespective of treatment or donor, while the concentration of butyrate was lower after nitrate addition in the nitrate-receiving microcosms. In conclusion, nitrate influences the composition and biochemistry of oral microcosms, although the result is strongly dependent on the inoculum

Risk, clinical course, and outcome of ischemic stroke in patients hospitalized with COVID-19: a multicenter cohort study

Background and Purpose: The frequency of ischemic stroke in patients with coronavirus disease 2019 (COVID-19) varies in the current literature, and risk factors are unknown. We assessed the incidence, risk factors, and outcomes of acute ischemic stroke in hospitalized patients with COVID-19. Methods: We included patients with a laboratory-confirmed SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) infection admitted in 16 Dutch hospitals participating in the international CAPACITY-COVID registry between March 1 and August 1, 2020. Patients were screened for the occurrence of acute ischemic stroke. We calculated the cumulative incidence of ischemic stroke and compared risk factors, cardiovascular complications, and in-hospital mortality in patients with and without ischemic stroke. Results: We included 2147 patients with COVID-19, of whom 586 (27.3%) needed treatment at an intensive care unit. Thirty-eight patients (1.8%) had an ischemic stroke. Patients with stroke were older but did not differ in sex or cardiovascular risk factors. Median time between the onset of COVID-19 symptoms and diagnosis of stroke was 2 weeks. The incidence of ischemic stroke was higher among patients who were treated at an intensive care unit (16/586; 2.7% versus nonintensive care unit, 22/1561; 1.4%; P=0.039). Pulmonary embolism was more common in patients with (8/38; 21.1%) than in those without stroke (160/2109; 7.6%; adjusted risk ratio, 2.08 [95% CI, 1.52-2.84]). Twenty-seven patients with ischemic stroke (71.1%) died during admission or were functionally dependent at discharge. Patients with ischemic stroke were at a higher risk of in-hospital mortality (adjusted risk ratio, 1.56 [95% CI, 1.13-2.15]) than patients without stroke. Conclusions: In this multicenter cohort study, the cumulative incidence of acute ischemic stroke in hospitalized patients with COVID-19 was approximate to 2%, with a higher risk in patients treated at an intensive care unit. The majority of stroke patients had a poor outcome. The association between ischemic stroke and pulmonary embolism warrants further investigation.Paroxysmal Cerebral Disorder

The Dutch Parelsnoer Institute Cerebrovascular Disease Initiative: a retrospective study of the effects of integrating clinical care and research on costs and quality of care in patients with ischaemic stroke

INTRODUCTION: The Dutch Parelsnoer Institute (PSI) is a collaboration between all university medical centres in which clinical data, imaging and biomaterials are prospectively and uniformly collected for research purposes. The PSI has the ambition to integrate data collected in the context of clinical care with data collected primarily for research purposes. We aimed to evaluate the effects of such integrated registration on costs, efficiency and quality of care. METHODS: We retrospectively included patients with cerebral ischaemia of the PSI Cerebrovascular Disease Consortium at two participating centres, one applying an integrated approach on registration of clinical and research data and another with a separate method of registration. We determined the effect of integrated registration on (1) costs and time efficiency using a comparative matched cohort study in 40 patients and (2) quality of the discharge letter in a retrospective cohort study of 400 patients. RESULTS: A shorter registration time (mean difference of -4.6 min, SD 4.7, p=0.001) and a higher quality score of discharge letters (mean difference of 856 points, SD 40.8, p<0.001) was shown for integrated registration compared with separate registration. Integrated registration of data of 300 patients per year would save around euro700 salary costs per year. CONCLUSION: Integrated registration of clinical and research data in patients with cerebral ischaemia is associated with some decrease in salary costs, while at the same time, increased time efficiency and quality of the discharge letter are accomplished. Thus, we recommend integrated registration of clinical and research data in centres with high-volume registration only, due to the initial investments needed to adopt the registration software

The effect of propidium monoazide treatment on the measured bacterial composition of clinical samples after the use of a mouthwash

Objectives The use of an anti-microbial mouthwash results not only in a reduction of the number of viable cells in dental plaque but potentially also in a shift in the oral microbiome. DNA-based techniques may be appropriate to monitor these shifts, but these techniques amplify DNA from both dead and living cells. Propidium monoazide (PMA) has been used to overcome this problem, by preventing the amplification of DNA from membrane-damaged cells. The aim of this study was to evaluate the use of PMA when measuring compositional shifts in clinical samples after mouthwash use. Materials and methods On two consecutive days, baseline samples from buccal surfaces, tongue, and saliva were obtained from six volunteers, after which they used a mouthwash (Meridol, GABA, Switzerland) twice daily for 14 days. Subsequently similar samples were obtained on two consecutive days. The microbial composition of the samples, with or without ex vivo PMA treatment, was assessed with 16S rRNA gene amplicon sequencing. Results Data showed a clear effect of mouthwash usage on the tongue and saliva samples. PMA treatment enhanced the observed differences only for the saliva samples. Mouthwash treatments did not affect the composition of the plaque samples irrespective of the use of PMA. Conclusion The necessity to use a PMA treatment to block the DNA from dead cells in clinical studies aimed at measuring compositional shifts after the use of a mouthwash is limited to salivary samples. Clinical relevance Measuring shifts in the oral microbiome could be hampered by the presence of DNA from dead cells