Invasive Group A Streptococcal Infections in Ontario, Canada: 1992–2013
Bibliographic record
Abstract
Background. Invasive Group A streptococcal (iGAS) infections continue to cause significant morbidity and mortality. We explored trends in incidence, M-type, disease presentation, outcome, and antimicrobial resistance of iGAS infections in Ontario, Canada over a 22-year period. Methods. TIBDN has performed a prospective, population-based surveillance for all iGAS infections in metropolitan Toronto and Peel regions in Ontario, Canada since 1 January 1992. Clinical information was collected from health care providers. M typing was performed from January 1992 to September 2006 and emm typing from October 2006 to December 2013. Results. Overall, 2282 episodes of iGAS were identified; 1074 in the “former” cohort (1992-2002) and 1212 in the “recent” cohort (2003-2013). The average incidence per 100,000 residents was 2.7 in the former cohort and 2.8 in the recent cohort (p = 0.69). For each cohort, the most common clinical presentation was skin and soft-tissue infections, 47.8% and 43.3%. The percentage of cases of streptococcal toxic shock syndrome increased from 15.6% of patients in the former cohort to 19.3% in recent cohort (p = 0.08), while cases of necrotizing fasciitis decreased from 8.4% to 6.1% (p = 0.02). Case fatality rates declined over time, from 16.8% in 1992-5 to 13.6% in 2010-13 (p = 0.06). Both nosocomial and nursing home-associated infections declined significantly from 12.9% to 8.3% (p = 0.01) and 7.4% to 4.2% (p = 0.009), respectively. M serotype distribution varied substantially from year to year (M3 from 0 to 19.7%, M1 from 7.4-37%) but remained stable over each cohort, with the exception of the emergence of M89 in the recent cohort. M1 was consistently the most common and exhibited a four to five year cyclical pattern. Erythromycin resistance increased from 2.2% in 1992-1995 to 19.5% in 2008-2010, then declined to 7.5% in 2013. Conclusion. The overall incidence of iGAS remains unchanged over 22 years. The proportion of hospital and nursing home-associated cases has decreased, as have case fatality rates. M1 infections have a 4-5 year periodicity, M89 has emerged, and erythromycin resistance has varied significantly over time. An effective vaccine will be required to substantially reduce iGAS morbidity and mortality. Disclosures. All authors: No reported disclosures.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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 teacher head, 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".