Search

The emergence of high-throughput DNA sequencing methods provides unprecedented opportunities to further unravel bacterial biodiversity and its worldwide role from human health to ecosystem functioning. However, despite the abundance of sequencing studies, combining data from multiple individual studies to address macroecological questions of bacterial diversity remains methodically challenging and plagued with biases. Here, using a machine-learning approach that accounts for differences among studies and complex interactions among taxa, we merge 30 independent bacterial data sets comprising 1,998 soil samples from 21 countries. Whereas previous meta-analysis efforts have focused on bacterial diversity measures or abundances of major taxa, we show that disparate amplicon sequence data can be combined at the taxonomy-based level to assess bacterial community structure. We find that rarer taxa are more important for structuring soil communities than abundant taxa, and that these rarer taxa are better predictors of community structure than environmental factors, which are often confounded across studies. We conclude that combining data from independent studies can be used to explore bacterial community dynamics, identify potential ‘indicator’ taxa with an important role in structuring communities, and propose hypotheses on the factors that shape bacterial biogeography that have been overlooked in the past.

The emergence of high-throughput DNA sequencing methods provides unprecedented opportunities to further unravel bacterial biodiversity and its worldwide role from human health to ecosystem functioning. However, despite the abundance of sequencing studies, combining data from multiple individual studies to address macroecological questions of bacterial diversity remains methodically challenging and plagued with biases. Here, using a machine-learning approach that accounts for differences among studies and complex interactions among taxa, we merge 30 independent bacterial data sets comprising 1,998 soil samples from 21 countries. Whereas previous meta-analysis efforts have focused on bacterial diversity measures or abundances of major taxa, we show that disparate amplicon sequence data can be combined at the taxonomy-based level to assess bacterial community structure. We find that rarer taxa are more important for structuring soil communities than abundant taxa, and that these rarer taxa are better predictors of community structure than environmental factors, which are often confounded across studies. We conclude that combining data from independent studies can be used to explore bacterial community dynamics, identify potential ‘indicator’ taxa with an important role in structuring communities, and propose hypotheses on the factors that shape bacterial biogeography that have been overlooked in the past.

OBJECTIVES: To characterise the costs to the UK National Health Service of cardiovascular (CV) events among individuals receiving lipid-modifying therapy. DESIGN: Retrospective cohort study using Clinical Practice Research Datalink records from 2006 to 2012 to identify individuals with their first and second CV-related hospitalisations (first event and second event cohorts). Within-person differences were used to estimate CV-related outcomes. SETTING: Patients in the UK who had their first CV event between January 2006 and March 2012. PARTICIPANTS: Patients ≥18 years who had a CV event and received at least 2 lipid-modifying therapy prescriptions within 180 days beforehand. PRIMARY AND SECONDARY OUTCOME MEASURES: Direct medical costs (2014 £) were estimated in 3 periods: baseline (pre-event), acute (6 months afterwards) and long-term (subsequent 30 months). Primary outcomes included incremental costs, resource usage and total costs per period. RESULTS: There were 24 093 patients in the first event cohort of whom 5274 were included in the second event cohort. The mean incremental acute CV event costs for the first event and second event cohorts were: coronary artery bypass graft/percutaneous transluminal coronary angioplasty (CABG/PTCA) £5635 and £5823, myocardial infarction £4275 and £4301, ischaemic stroke £3512 and £4572, heart failure £2444 and £3461, unstable angina £2179 and £2489 and transient ischaemic attack £1537 and £1814. The mean incremental long-term costs were: heart failure £848 and £2829, myocardial infarction £922 and £1385, ischaemic stroke £973 and £682, transient ischaemic attack £705 and £1692, unstable angina £328 and £677, and CABG/PTCA £-368 and £599. Hospitalisation accounted for 95% of acute and 61% of long-term incremental costs. Higher comorbidity was associated with higher long-term costs. CONCLUSIONS: Revascularisation and myocardial infarction were associated with the highest incremental costs following a CV event. On the basis of real

OBJECTIVES: Parkinson's Disease patients wore a device on the wrist that gave reminders to take levodopa and also measured bradykinesia and dyskinesia. Consumption of medications was acknowledged by placing the thumb on the device. Some patients performed this acknowledgement repeatedly and unconsciously. This study examines whether this behaviour reflected increased impulsivity. METHODS AND RESULTS: Twenty five participants were selected because they had i) excess acknowledgements described above or ii) Impulsive-Compulsive Behaviours or iii) neither of these. A blinded assessor applied clinical scales to measure Impulsive-Compulsive Behaviours, cognition, depression, anxiety and apathy. A Response Ratio, representing the number of acknowledgements/number of doses (expressed as a percentage) was tightly correlated with ratings of Impulsive-Compulsive Behaviours (r² = 0.79) in 19/25 subjects. Some of these patients had dyskinesia, which was higher with extraneous responses than with response indicating medication consumption. Six of the 25 subjects had high Impulsive-Compulsive Behaviour Scores, higher apathy scores, low levels of dyskinesia and normal Response Ratios. Patients without ICB (low RR) also had low dyskinesia levels regardless of the relevance of the response. CONCLUSION: An elevated Response Ratio is a specific measure of a type of ICB where increased incentive salience is attributed to cues by the presence of high striatal dopamine levels, manifested by high levels of dyskinesia. This study also points to a second form of ICBs which occur in the absence of dyskinesia, has normal Response Ratios and higher apathy scores, and may represent prefrontal pathology.