Staphylococcus aureus bacteremia: A review on the detection of metastatic infections

Staphylococcus aureus is an important cause of both community-acquired and healthcare-associated bacteremia. The aim of this study was to identify foci of metastatic infection, risk factors for metastatic infection and their impact on mortality in patients with S. aureus bacteremia. A retrospective study was conducted between January 1, 2019 and January 1, 2022. A total of 104 adult patients with S. aureus isolated from blood cultures were evaluated by an infectious disease physician and included in the study. Patient data were analyzed using logistic regression to identify risk factors for metastatic infection and their impact on mortality. Metastatic infection occurred in 62% of the 104 patients: skin soft tissue infections (20%), spondylitis/spondylodiscitis (20%), endocarditis (18%), paravertebral/epidural abscesses (17%) and others. Metastatic infections were less common in patients with catheters and healthcare-associated bacteremia. Elevated levels of C-reactive protein and erythrocyte sedimentation rate were significantly associated with metastatic infections. Community-acquired and persistent bacteremia increased the likelihood of metastatic infection by 7.6-fold and 4.8-fold, respectively. The six-month mortality rate was 21% and was similar in the group with and without metastatic infections. Persistent bacteremia and advanced age increased mortality by 3.2-fold and one-fold, respectively. In conclusion, metastatic infections are common in S. aureus bacteremia. Infectious disease consultation is important for detecting metastatic foci and reducing mortality. Elevation of acute phase reactants, mode of acquisition and persistence of bacteremia are indicators of metastatic infection. It should be acknowledged that mortality increases with persistent bacteremia and advanced age and these patients should be followed closely.