Detection of septic metastases in catheter-related Staphylococcus aureus bacteremia using 18FFDG-PET/CT: a before-and-after study.

Purpose: To evaluate the detection rate of septic metastases in catheter-related S. aureus bacteremia (CR-SAB) episodes by using [18F]FDG-PET/CT.

Methods: We conducted a retrospective, before-and-after, single-center study of a prospectively identified catheter-related SAB (CR-SAB) cohort at Hospital Clínic Barcelona. All adult patients hospitalized from January 2006 to December 2022 were included. Primary outcome was the detection of septic metastases before and after integrating [18F]FDG-PET/CT into the diagnostic workflow of CR-SAB in January 2020. Secondary outcomes included 30-day mortality, length of stay, and treatment duration.

Results: A total of 598 episodes of CR-SAB were included, 100 in the post-intervention period (2020-2022) and 498 in the pre-intervention period (2006-2019). [18F]FDG-PET/CT scan was performed in 28/100 episodes (28.0%) in post-intervention period, versus 9/498 in pre-intervention period (1.8%). Septic metastases detection rate was higher after [18F]FDG-PET/CT implementation (22/100, 22% vs. 56/498, 11.2% p .004), mainly due to pulmonary septic emboli (13/100, 13.0% vs. 12/498, 2.4% p < .001) and osteoarticular seeding (7/100, 7.0% vs. 11/498, 2.2% p .019). Neither pulmonary septic emboli nor osteoarticular metastases increased 30-day mortality (3/25, 12.0% vs. 57/573, 10.0%, p .732; and 2/18, 11.1% vs. 58/580 10.0%, p .702, respectively). Patients with septic metastases had longer treatment [25.0 (16.0-37.0) vs. 15.0 (13.0-19.0) days, p < .001].

Conclusions: [18F]FDG-PET/CT use in patients with CR-SAB was associated with a higher rate of septic metastases diagnosis, mainly pulmonary and osteoarticular, resulting in longer treatment, but no differences in clinical outcomes were observed.