Novel Findings in the Epidemiology of Staphylococcus aureus in Patients Attending Inner City Sexually Transmitted Infections (STI) and Community Clinics in Calgary
Bibliographic record
Abstract
Background. The predominant site of carriage of community acquired methicillin-resistant S. aureus (CA-MRSA) is not known. We designed a prospective cohort study to measure the prevalence of carriage of SA, sites of colonization and risk factors associated with SA colonization in an inner city population in Calgary attending for STIs or general medical evaluation. Methods. Following Ethics Board approval, written informed consent was obtained, a 50–item questionnaire was completed and swabs from nares, throat, axilla, groin, perineal-perianal, vaginal, upper back and interdigital web spaces (IDWS) were obtained. Following broth enrichment MSSA/MRSA were identified using standard laboratory procedures and confirmed by PCR assay (nuc, femA and mecA). Molecular characterization was done with pulsed-field electrophoresis (PGFE), SCCmec typing, spa and Multi Locus Sequence Typing (MLST). Risk factor data were collated and uni- and multivariate analyses were performed on STATA 9.2). Results. Of 285 participants included in the final analysis, the prevalence of colonization by SA for any site was 57.5%, (66.4% males/33.5% females). MSSA carriage prevalence was 56.1% and 1.4% for MRSA (2 of 4 carried the USA300 strain). The most common site of MSSA colonization was the throat (41.4%) as a single or multiple site. The back and IDWS showed a colonization rate of 7.7 and 11.6%, respectively. Univariate analysis of risk factors associated with SA colonization of any site were as follows: use of illicit drugs with strangers (p = 0.01), >6 heterosexual partners (p = 0.002), oral sex (0.01), trimming pubic hair (p = 0.007), any sports with mats (p = 0.005). Only the first 2 variables remained significant on the multivariate analysis. We found 12 MSSA carriers with a strain closely related to USA300-MRSA by PFGE, MSLT and spa profile. Conclusion. We found a very high prevalence of MSSA colonization in this population - 57.5% versus a usual prevalence of 22-32%. Two novel sites were identified for SA carriage: the upper back and the IDWS. The throat appears to be a significant reservoir of SA colonization in this population, which has implications for transmission. Strain relatedness between MSSA ST8 isolates and USA300-MRSA strain suggest a horizontal gain or loss of the SCCmec element. 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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".