Low-risk Staphylococcus aureus bacteremia patients do not require routine diagnostic imaging: A multicenter retrospective cohort study.

Abstract

Risk stratification to categorize patients with Staphylococcus aureus bacteremia (SAB) as low- or high-risk for metastatic infection may direct diagnostic evaluation and enable personalized management. We investigated the frequency of metastatic infections in low-risk SAB patients, their clinical relevance, and whether omission of routine imaging is associated with worse outcomes. We performed a retrospective cohort study in seven Dutch hospitals among adult patients with low-risk SAB, defined as hospital-acquired infection without treatment delay, absence of prosthetic material, short duration of bacteremia, and rapid defervescence. The primary outcome was the proportion of patients whose treatment plan changed due to detected metastatic infections, as evaluated by both the actual therapy administered and by linking a retrospectively adjudicated diagnosis to guideline-recommended treatment. Secondary outcomes were 90-day relapse-free survival, and factors associated with performing of diagnostic imaging. Of 377 patients included, 298 (79%) underwent diagnostic imaging. In 15 of these 298 patients (5.0%) imaging findings during patient admission had been interpreted as metastatic infections that should extend duration of treatment. Using the final adjudicated diagnosis, 4 patients (1.3%) had clinically relevant metastatic infection. In a multilevel multivariable logistic regression analysis, 90-days relapse-free survival was similar between patients without imaging and those who underwent imaging (81.0% versus 83.6%; aOR 0.749 (95% CI 0.373-1.504). Our study advocates risk stratification for the management of patients with SAB. Prerequisites are follow-up blood cultures, bedside ID consultation, along with critically reviewing disease evolution. Using this approach, routine imaging could be omitted in low-risk patients.