Journal Club

Incorporating PET/CT Scans into the Evaluation of S. aureus Bacteremia

By Christopher J. Graber, MD, MPH, FIDSA

Staphylococcus aureus bacteremia remains a high-morbidity, high-mortality condition. A thorough search for source and potential complications can improve outcomes. Fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) has been advocated as a part of the diagnostic workup of prosthetic valve endocarditis in European guidelines, but a recent study published in Clinical Infectious Diseases evaluated the potential role it may have in the routine workup of any S. aureus bacteremia.

Investigators at an academic medical center in Israel conducted PET/CT in 151 bacteremia episodes in 149 patients with S. aureus bacteremia, 124 of which were specifically recruited as a part of a research protocol and 25 who underwent PET/CT at the discretion of their treating physician. These patients were matched to 151 episodes in 150 control patients by age, comorbidity score, and methicillin susceptibility. PET/CT resulted in findings suggestive of at least one infectious focus in 107 (70.8%) episodes and resulted in new findings detected first by PET/CT in 72 (67.2%) of these episodes, including 31 bone and joint and 28 lung infections. As a result of PET/CT, interventions focusing on source control were performed in 27 (17.9%). Ninety-day mortality was significantly lower in the PET/CT cohort (21 vs. 43, P = .002) and remained significant in multivariate analysis, though the groups differed in that PET/CT patients more frequently had community or health care-associated bacteremia onset and higher frequency of bacteremia >3 days and less frequently had solid malignancy. PET/CT patients underwent more interventions, received longer durations of antibiotics, and had longer hospitalizations.

While not a randomized study, this work nonetheless suggests that PET/CT frequently changes management for the better in a large proportion of patients with S. aureus bacteremia and may be closer to being routinely recommended in its management.

(Ghanem-Zoubi et al. Clin Infect Dis. Published online: July 8, 2020.)