Epidemiology and Clinical Outcomes of Serratia marcescens Infections in Adults With Cystic Fibrosis
Bibliographic record
Abstract
Background. Cystic fibrosis (CF) airway infections are often viewed as being confined to a few classical pathogens such as Pseudomonas aeruginosa, Staphylococcus aureus, Burkholderia cepacia complex, and Stenotrophomonas maltophilia. However, a range of other organisms are commonly observed in CF; organisms where the epidemiology, natural history and clinical consequences are not understood. Herein we sought to characterize Serratia marcescens infections in adults with CF. Methods. We retrospectively audited the Calgary Adult CF program clinical records to identify patients with a history of sputum S. marcescens isolation. Baseline demographics were assessed. We compared those with sustained infection to patients with only transient isolation, as well as to age and time-matched patients with no history of S. marcescens infection to identify risk factors for infection and various outcomes such as lung function decline, mortality and lung transplantation. Results. Over the study period 9.4% of patients (29/318) had sputum positive on at least one occasion for S. marcescens. While 18 patients had transient infections clearing immediately, 11 patients had sustained infection (median 9.1 months, IQR 5–30 months). Pulmonary exacerbation was only observed in 48% of cases at incident isolation and did not differ significantly between incident transient and sustained infections. From the time of incident isolation, the number of pulmonary exacerbations was significantly increased in the following year in only those with transient infection. Compared to matched controls without S. marcescens, patients with sustained infection did not differ significantly in 5-year mortality (45% versus 23%, p = 0.64) or lung transplantation (18% versus 0%, p = 0.11). Conclusion. S. marcescens was identified as a relatively common organism from sputum culture in patients with CF. Approximately one third of patients experienced prolonged carriage of the organisms in their lower airways, but none persisted indefinitely with all eventually clearing infection. No evidence of short or long-term deleterious consequences were noted in our cohort. 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) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 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) | 0.001 | 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".