Assessing phage-host population dynamics by reintroducing virulent viruses to synthetic microbiomes.

Microbiomes feature complex interactions between diverse bacteria and bacteriophages. Synthetic microbiomes offer a powerful way to study these interactions; however, a major challenge is obtaining a representative bacteriophage population during the bacterial isolation process. We demonstrate that colony isolation reliably excludes virulent viruses from sample sources with low virion-to-bacteria ratios such as feces, creating "virulent virus-free" controls. When the virulent dsDNA virome is reintroduced to a 73-strain synthetic gut microbiome in a bioreactor model of the human colon, virulent viruses target susceptible strains without significantly altering community structure or metabolism. In addition, we detected signals of prophage induction that associate with virulent predation. Overall, our findings indicate that dilution-based isolation methods generate synthetic gut microbiomes that are heavily depleted, if not devoid, of virulent viruses and that such viruses, if reintroduced, have a targeted effect on community assembly, metabolism, and prophage replication.

Physical environment features that predict outdoor active play can be measured using Google Street View images.

BACKGROUND: Childrens' outdoor active play is an important part of their development. Play behaviour can be predicted by a variety of physical and social environmental features. Some of these features are difficult to measure with traditional data sources. METHODS: This study investigated the viability of a machine learning method using Google Street View images for measurement of these environmental features. Models to measure natural features, pedestrian traffic, vehicle traffic, bicycle traffic, traffic signals, and sidewalks were developed in one city and tested in another. RESULTS: The models performed well for features that are time invariant, but poorly for features that change over time, especially when tested outside of the context where they were initially trained. CONCLUSION: This method provides a potential automated data source for the development of prediction models for a variety of physical and social environment features using publicly accessible street view images.

Development of a Risk Prediction Model for Assessing Dental Readiness in the Canadian Armed Forces.

INTRODUCTION: The establishment and sustainment of a high state of dental readiness in the Canadian Armed Forces (CAF) are the primary missions of the Royal Canadian Dental Corps. The objective of this study was to develop a risk prediction tool to estimate dental readiness in active CAF personnel. MATERIALS AND METHODS: The prediction model was developed to predict the classification of non-deployable (yes/no) within 12 months (primary) and 18 months (secondary) using both dental history data (including dental attendance, restorations, root canals, and third molar status) and demographic information. Two cohorts were used for development: a recruit cohort who enrolled between April 2016 and March 2017 and a longer-serving member (LSM) cohort who had their recall dental exam between May 2014 and October 2014. Each group was followed until April 26, 2018. Elastic net logistic regression models were used to create the models. Model performance was evaluated using area under the curve, F1, and the Brier score. RESULTS: The recruit cohort included 2,828 individuals and the LSM cohort included 2,398 individuals. Overall, the classification of non-deployable occurred in 5.1% of the study population within 12 months and 9.6% of the population within 18 months. The models predicted the outcome with an area under the receiver operating curve of 0.77 in recruits and 0.70 in LSMs. CONCLUSION: The prediction model shows potential but its performance and usability could be further improved through the consistent collection of high quality, discretely entered, epidemiological data following standardized diagnostic terminology and coding. A recalibrated and automated version of this model could assist in decision making, resource allocation, and the enhancement of military dental readiness.

Community water fluoridation exposure and dental caries experience in newly enrolled members of the Canadian Armed Forces 2006-2017.

OBJECTIVES: This cross-sectional study examines the dental caries experience of new Canadian Armed Forces (CAF) members in relation to enrollment from municipalities with and without water fluoridation. METHODS: The study population consisted of recruits who enrolled in the CAF between 2006 and 2017 with an enrollment address in municipalities with known fluoridation status (n = 24,552). Odontogram statistics from dental examinations were used to calculate the number of decayed, missing, and filled teeth (DMFT) and tooth surfaces (DMFS) for each recruit. The average difference between recruits from municipalities with and without fluoridation was determined using a linear regression model which adjusted for confounding by age and gender and allowed effect modification based on socio-economic status. RESULTS: The average recruit was male, 24 years of age, with 5.6 DMFT and 11.6 DMFS. After adjusting for age and gender, recruits residing in municipalities with water fluoridation had lower DMFT by 0.67 (CI - 0.55, - 0.79) points and lower DMFS by 1.77 (- 1.46, - 2.09) points. When allowing for effect modification by median income quintile of the recruits' home census tract, the average reduction in DMFT and DMFS was similar in all income quintiles, with average reductions in DMFT ranging from 0.47 to 1.02 and average reductions in DMFS ranging from 1.33 to 2.70. CONCLUSION: Residence in a municipality with water fluoridation was associated with reduced caries experience in a national sample of newly enrolled CAF members. The benefits of water fluoridation were uniform across neighbourhood income and military rank classes.

RéSUMé: OBJECTIFS: Cette étude transversale examine l'importance du niveau de la carie dentaire des nouveaux membres des Forces armées canadiennes (FAC) par rapport à l'enrôlement provenant des municipalités avec et sans fluoration de l'eau. MéTHODES: La population étudiée était constituée de recrues qui se sont enrôlés dans les FAC entre 2006 et 2017 avec une adresse d'inscription dans les municipalités dont le statut de fluoration est connu (n = 24 552). Les statistiques en provenance des odontogrammes des examens dentaires ont été utilisées pour calculer le nombre de dents et surfaces cariés, absents et obturés (CAOD & CAOF) pour chaque recrue. La différence moyenne entre les recrues des municipalités avec ou sans fluoration a été déterminée à l'aide d'un modèle de régression linéaire qui a été ajusté pour prendre en considération l'âge et le sexe et a permis une modification de l'effet en fonction du statut socioéconomique. RéSULTATS: La recrue moyenne était un homme de 24 ans avec 5,6 CAOD et 11,6 CAOF. Après ajustement en fonction de l'âge et du sexe, les recrues résidant dans les municipalités avec fluoration de l'eau avaient un CAOD inférieur de 0,67 points (IC -0,55, -0,79) et un CAOF inférieur de 1,77 points (-1,46, -2,09). En permettant la modification de l'effet par l'indice de revenu médian du secteur de recensement d'origine des recrues, la réduction moyenne du CAOD et du CAOF était similaire dans tous les niveaux de revenu, avec des réductions moyennes du CAOD d'entre 0,47 et 1,02 et des réductions moyennes du CAOF d'entre 1,33 et 2,70. CONCLUSION: La résidence dans une municipalité avec fluoration de l'eau a été associée avec une réduction des caries dans un échantillonnage national de nouveaux membres enrôlés dans les FAC. Les avantages de la fluoration de l'eau étaient uniformes dans l'ensemble des niveaux de revenu du quartier et des différentes classes de grade militaire.

Caregiver Out-of-Pocket Costs for Octogenarian Intensive Care Unit Patients in Canada.

ABSTRACTMedical issues facing the aging population are of growing concern with consequences for patients and their caregivers. This study determined the indirect and out-of-pocket costs incurred by the caregivers of elderly patients in Canadian Intensive Care Units (ICUs). Primary family caregivers were surveyed capturing out-of-pocket costs, hours of work, and hours of leisure forgone in providing patient care while the patient was in the ICU. Total costs of care per month were reported across caregiver sex, age, and geographic region. Average out-of-pocket costs were $791 (2016 Canadian dollars) in the first month of ICU care. The mean total cost to family caregivers per patient was $162 per day. Male primary caregivers had higher mean out-of-pocket costs than female caregivers. Subsidization programs covering expenses such as travel, meals, accommodation, and parking are needed to support family caregivers of elderly ICU patients who are incurring considerable out-of-pocket costs.

Gender-specific associations between involvement in team sport culture and canadian adolescents' substance-use behavior.

Canadian adolescents have some of the highest rates of substance use in the world. The etiology of this phenomenon has not been fully explored, and one possible contextual determinant is involvement in sport activities that foster risk-taking behaviors through physical and social mechanisms. Using the 2013-14 Health Behaviour in School Aged Children (HBSC) study we therefore examined this hypothesis in a contemporary national sample of Canadian adolescents. The strength and direction of the relationship between sport and substance use varied by gender and substance, with team sport participation associated with increased binge drinking (RR 1.33 [95% CI 1.13-1.56] for boys, RR 1.21 [1.06-1.38] for girls) and use of smokeless tobacco (RR 1.68 [1.34-2.10] for boys, RR 1.32 [1.01-1.72] for girls), but with lower prevalence levels of cannabis use (RR 0.73 [95% CI 0.61-0.88]) and cigarette smoking (RR 0.79 [95% CI 0.70-0.89]) in girls alone. We also compared team sport athletes with high social involvement (sports team as primary peer group) and physical involvement (higher number of days/week physically active) to those with low involvement. For boys, the combination of high physical and high social involvement was associated with the highest risk, while high social involvement alone was associated with the greatest risk for girls. While team sport participation confers only a small increased risk for substance use, the prevalence of sport participation results in a large population impact. Given this fact, interventions such as education for parents and coaches and policies encouraging engagement in a variety of extracurricular activities should be explored.