Comparability of microbiota of swabbed and spit saliva.

In general, saliva is used for microbiota analysis in longitudinal studies, and several collection methods are being used. Using a robust sample collection procedure is important, as it may influence salivary composition. This study explored the comparability of the microbiota of swabbed and spit saliva. Twenty-two females participated in this cross-sectional study. The bacterial composition of the three saliva samples (swab collected by the participant (SW-P), swab collected by the researcher (SW-R), and spit (SP) was assessed by 16S rRNA gene amplicon sequencing. The bacterial composition of the swabbed and the spit saliva was significantly different irrespective of the operator, and Shannon diversity was significantly higher in spit saliva than in SW-P and SW-R. The salivary microbiota of spit and swabbed adult saliva differs significantly. Research on microbial composition therefore requires collection of similar saliva sample types in all study participants.

Oral health determinants of incident malnutrition in community-dwelling older adults.

OBJECTIVE: Poor oral health might be a modifiable determinant of malnutrition in older age. We aimed to investigate the associations of multiple oral health characteristics with incident malnutrition in community-dwelling older adults. METHODS: This exploratory analysis is based on prospective data from 893 participants, aged 55-80 years without malnutrition in 2005/06 from the Longitudinal Aging Study Amsterdam. In 2007, 19 oral health characteristics from the domains teeth/dentures, oral hygiene, oral problems, and self-rated oral health were assessed by questionnaire. Incident malnutrition was defined as presence of low body mass index (<20 kg/m² in people <70 years, <22 kg/m² ≥70 years) and/or self-reported involuntary weight loss ≥5% in previous 6 months at any of the follow-ups (2008/09, 2012/13, 2015/16). Associations of oral aspects with incident malnutrition were analyzed by cox proportional hazard models and adjusted for confounders. RESULTS: The 9-year incidence of malnutrition was 13.5%. Sixteen of 19 oral health aspects were not associated with incident malnutrition in the crude models. Adjusted hazard ratios for incident malnutrition were 2.14 (1.10-4.19, p = 0.026) for toothache while chewing, 2.10 (0.88-4.98, p = 0.094) for an unhealthy oral health status, and 1.99 (0.93-4.28, p = 0.077) for xerostomia in edentulous participants, however, the two latter ones failing to reach statistical significance. CONCLUSIONS: We identified toothache while chewing as determinant of incident malnutrition in community-dwelling older adults, and found indications that poor oral health and xerostomia in combination with having no teeth may play a role in developing malnutrition. However, these outlined tendencies need to be proven in further studies. CLINICAL SIGNIFICANCE: Regarding the development of strategies to prevent malnutrition in older people toothache while chewing, xerostomia, and self-rated oral health would be of specific interest as these factors are modifiable and can be easily assessed by self-reports.

On the ecosystemic network of saliva in healthy young adults.

A dysbiotic state is believed to be a key factor in the onset of oral disease. Although oral diseases have been studied for decades, our understanding of oral health, the boundaries of a healthy oral ecosystem and ecological shift toward dysbiosis is still limited. Here, we present the ecobiological heterogeneity of the salivary ecosystem and relations between the salivary microbiome, salivary metabolome and host-related biochemical salivary parameters in 268 healthy adults after overnight fasting. Gender-specific differences in the microbiome and metabolome were observed and were associated with salivary pH and dietary protein intake. Our analysis grouped the individuals into five microbiome and four metabolome-based clusters that significantly related to biochemical parameters of saliva. Low salivary pH and high lysozyme activity were associated with high proportions of streptococcal phylotypes and increased membrane-lipid degradation products. Samples with high salivary pH displayed increased chitinase activity, higher abundance of Veillonella and Prevotella species and higher levels of amino acid fermentation products, suggesting proteolytic adaptation. An over-specialization toward either a proteolytic or a saccharolytic ecotype may indicate a shift toward a dysbiotic state. Their prognostic value and the degree to which these ecotypes are related to increased disease risk remains to be determined.