Risk of Infection Among Patients Colonized With MRSA in an Acute Care Hospital, 2000–2012
Bibliographic record
Abstract
Background. To describe risk factors for MRSA clinical isolates among colonized patients, 2000–2012. Methods. Laboratory-based surveillance of incident MRSA cases (MRSA infected or colonized patients) was conducted from 2000 to 2012 at Mount Sinai Hospital (MSH) in Toronto. MSH has active MRSA screening and control programs. Demographic/clinical data were extracted from patient charts/infection control records. Strains were typed by PFGE of SmaI-digested genomic DNA. Results. 2017 incident cases of MRSA were identified. The majority were CMRSA2/USA100/800 (50%), CMRSA10/USA300 (23%) and CMRSA1/USA600 (13%). The initial positive culture was from a clinical specimen in 600 cases, from both screening and clinical specimens in 126, and from screening specimens only in 1291. 522 cases were acquired at MSH; 1495 were identified on admission. Of 1291 initially colonized patients, 843 (65%) had a positive nasal culture, 406 (31%) had negative nasal but positive rectal culture, and 44 (3%) had positive culture from a wound swab only; 190 (16%) had a clinical isolate within a year (figure). Patients with nosocomial MRSA were more likely than admission cases to have a subsequent clinical isolate (21% versus 14%; P < .01) and to be identified via rectal swab (49% nosocomial versus 27% on admission; P < .001). Although the percent of cases with a subsequent clinical isolate was similar for nasal- and rectal- colonized nosocomial cases (21%), those with a positive nasal culture had a shorter period between initial positive screening culture and clinical isolate (median 5 days (IQR 1-18) versus median 13 days (IQR 5-47); P = .02). CMRSA10 cases were more likely male, younger, and admission positive. CMRSA1 cases were more likely nosocomial and initially isolated from a rectal site only. Conclusion. More than 1 in 5 patients who became colonized with MRSA in hospital developed infection (median time to infection = 9 days), supporting programs to eradicate colonization in such patients. The importance of non-nasal swabs in identifying MRSA may depend on the particular circulating strains. Cases initially MRSA positive via nasal culture had a shorter period between initial screening culture and positive clinical isolate than those initially positive via rectal-culture only. Disclosures. All authors: No reported disclosures.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".