THE EPIDEMIOLOGY AND MICROBIOLOGY OF CLOSTRIDIUM DIFFICILE IN LONG-TERM CARE AND ACUTE CARE, AND CHARACTERIZATION OF THE FECAL MICROBIOTA IN ELDERLY INDIVIDUALS IN ONTARIO, CANADA
Bibliographic record
Abstract
This thesis is an investigation of Clostridium difficile in elderly patients in an acute care facility (ACF) and residents in a long-term care facility (LTCF) in southern Ontario, Canada. The first part of this thesis presents the findings of a cross-sectional study that describes the epidemiology and microbiology of C. difficile in elderly individuals. C. difficile was isolated from 92/410 (22.4%) ACF and 89/474 (18.8%) LTCF samples. Ribotypes 027 (35%) and 020 (10.4%) predominated the LTCF while ribotypes AI-82/1 (20.7%) and ribotype O (14.1%) predominated the ACF (P=0.031). In the LTCF, C. difficile colonization was associated with a history of Proton Pump Inhibitor (PPI) use (OR=2.05, P=0.003, 95% CI=1.20-3.49), and the interaction terms of male residents with prior medical leave of absence (OR=11.28, P=0.011. 95% CI=1.70-74.87), and a prior history of C. difficile infection (CDI) combined with fluoroquinolone use (OR=39.30, P=0.032, 95% CI=0.032). In the ACF, C. difficile colonization was associated with length of stay (OR=1.00, P=0.037, 95% CI=0.10-1.00), feeding through a tube (OR=4.83, P=0.001, 95% CI=1.95-11.97), antibiotic use (OR=4.36, P=0.050, 95% CI=1.00-18.95), immunosuppressive therapy (OR=8.09, P=0.001, 95% CI=2.24-29.22), and VRE colonization (OR=19.64, P=0.016, 95% CI=1.73-222.61), and the interaction terms for cephalosporin and fluoroquinolone use (OR=31.13, P=0.022 95% CI=1.51-1077.61), and prior CDI and cephalosporin use (OR=59.59, P=0.044, 95% CI=1.12-2854.07). The second part of this thesis describes the fecal microbiota of elderly individuals from ACF and LTCF, and evaluates the impact of PPIs, antibiotics, facility, and C. difficile colonization on microbial diversity, richness, evenness, community, and structure. Evenness and diversity were not affected by other risk factors. Facility and C. difficile colonization were associated with changes in relative abundance of key taxa. Community membership and structure were affected by facility. The changes identified in this study group, might better shape healthcare approaches in elderly, serving as indicators of health as well as aid in development of novel bacterial therapies. C. difficile colonization remains a complex and challenging issue, with the implications in its development of CDI still unclear. Given the potential for transmission by individuals colonized with C. difficile colonized, this area warrants further study.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".