title: Metastatic infectious disease and clinical outcome in Staphylococcus aureus and Streptococcus species bacteremia.
abstract: Early detection of metastatic infection in patients with Gram-positive bacteremia is important as morbidity and mortality are higher in the presence of these foci, probably due to incomplete eradication of clinically silent foci during initial treatment. We performed a prospective study in 115 patients with Staphylococcus aureus or Streptococcus species bacteremia with at least 1 risk factor for the development of metastatic foci, such as community acquisition, treatment delay, persistently positive blood cultures for >48 hours, and persistent fever >72 hours after initiation of treatment. An intensive search for metastatic infectious foci was performed including ¹⁸F-fluorodeoxyglucose-positron emission tomography in combination with low-dose computed tomography scanning for optimizing anatomical correlation (FDG-PET/CT) and echocardiography in the first 2 weeks of admission. Metastatic infectious foci were detected in 84 of 115 (73%) patients. Endocarditis (22 cases), endovascular infections (19 cases), pulmonary abscesses (16 cases), and spondylodiscitis (11 cases) were diagnosed most frequently. The incidence of metastatic infection was similar in patients with Streptococcus species and patients with S. aureus bacteremia. Signs and symptoms guiding the attending physician in the diagnostic workup were present in only a minority of cases (41%). An unknown portal of entry, treatment delay >48 hours, and the presence of foreign body material were significant risk factors for developing metastatic foci. Mean C-reactive protein levels on admission were significantly higher in patients with metastatic infectious foci (74 vs. 160 mg/L). FDG-PET/CT was the first technique to localize metastatic infectious foci in 35 of 115 (30%) patients. As only a minority of foci were accompanied by guiding signs or symptoms, the number of foci revealed by symptom-guided CT, ultrasound, and magnetic resonance imaging remained low. Mortality tended to be lower in patients without complicated infection compared to those with metastatic foci (16% vs. 25%, respectively). Five of 31 patients (16%) without proven metastatic foci died. In retrospect, 3 of these 5 patients likely had metastatic foci that could not be diagnosed while alive. In patients with Gram-positive bacteremia and a high risk of developing complicated infection, a structured protocol including echocardiography and FDG-PET/CT aimed at detecting metastatic infectious foci can contribute to improved outcome.
authors.affiliation: From the Departments of Medicine (FJV, BJK, CPBR), Nuclear Medicine (FJV, WJGO), Microbiology (PDS), Cardiology (APJvD), Gastroenterology (GJAW), Radboud University Nijmegen Medical Center, Nijmegen; Nijmegen Institute for Infection, Inflammation and Immunity (N4i) (FJV, BJK, PDS, WJGO, CPBR), Radboud University Nijmegen, and Department of Epidemiology (PFMK), Unit Health Technology Assessment, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Fidel J
authors.initials: FJ
authors.lastname: Vos
authors.forename: Bart Jan
authors.initials: BJ
authors.lastname: Kullberg
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Sturm
authors.forename: Paul F M
authors.initials: PFM
authors.lastname: Krabbe
authors.forename: Arie P J
authors.initials: APJ
authors.lastname: van Dijk
authors.forename: Geert J A
authors.initials: GJA
authors.lastname: Wanten
authors.forename: Wim J G
authors.initials: WJG
authors.lastname: Oyen
authors.forename: Chantal P
authors.initials: CP
authors.lastname: Bleeker-Rovers
mesh_terms: D000367:Age Factors; D016470:Bacteremia / Q000000981:diagnostic imaging* / Q000382:microbiology / Q000401:mortality*; D002097:C-Reactive Protein / Q000032:analysis; D003428:Cross Infection / Q000401:mortality; D015299:Discitis / Q000382:microbiology; D004452:Echocardiography; D004697:Endocarditis, Bacterial / Q000382:microbiology; D005260:Female; D019788:Fluorodeoxyglucose F18; D005547:Foreign Bodies; D006801:Humans; D008169:Lung Abscess / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012307:Risk Factors; D017192:Skin Diseases, Bacterial / Q000382:microbiology; D013203:Staphylococcal Infections / Q000000981:diagnostic imaging* / Q000382:microbiology / Q000401:mortality; D013211:Staphylococcus aureus; D013290:Streptococcal Infections / Q000000981:diagnostic imaging* / Q000382:microbiology / Q000401:mortality; D013291:Streptococcus; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D002097:C-Reactive Protein