Utility of 18F-FDG PET-CT Scan in Patients With Staphylococcus aureus Bacteremia

Background: Staphylococcus aureus bacteremia is a common yet serious infection with high morbidity and mortality. This study evaluated 18F-FDG PET-CT scan in regards to improving 30- and 90-day mortality in patients with S. aureus bacteremia. Methods: We retrospectively identified hospitalized adults with S. aureus bacteremia who underwent 18F-FDG PET-CT between November 2020 and November 2022 and selected age-matched controls who survived at least the mean culture-to-scan interval (7 days). Results: Of 132 hospitalized patients (66 who underwent 18F-FDG PET-CT and 66 matched controls; mean age 57±17 years), PET-CT identified previously unsuspected infectious foci in 57.57% (n=38/66), prompted antibiotic-course modification in 33.33% (n=22/66), and led to source-control procedures in 25.76% (n=17/66). Crude mortality did not differ significantly: 30-day, 6.1% vs. 16.7% ( P =0.10); 90-day, 18.2% vs. 16.7% ( P =1.00) for PET-CT and control groups, respectively. Landmark-adjusted Cox models likewise showed no mortality association with PET-CT (30-day aHR 0.42, 95% CI: 0.12–1.48, P =0.18; 90-day aHR 1.71, 0.59–4.95, P =0.32). Conclusions: These results underscore the potential clinical utility of 18F-FDG PET-CT in guiding therapeutic interventions. While we did not observe a statistically significant association with mortality in adjusted analyses, 18F-FDG PET-CT scans nevertheless offer a comprehensive assessment of infection localization and disease extent, enabling clinicians to identify occult foci of infection and tailor treatment strategies accordingly. The ability of 18F-FDG PET-CT scans to detect additional sources of infection beyond the bloodstream may facilitate prompt and targeted interventions.