Staph aureus bacteremia: New framework aims to personalize care

Clinical takeaway: Obtain follow-up blood cultures and promptly evaluate every patient with SAB for deep-seated or metastatic infection, revisiting risk as the clinical course evolves. Fourteen days of therapy may be appropriate when a thorough evaluation excludes such foci—even in some initially increased-risk patients—but persistent bacteremia or diagnostic uncertainty should prompt broader evaluation, renewed source-control efforts, and consideration of longer treatment.

Staphylococcus aureus is the leading cause of bloodstream infection–related death worldwide, and S aureus bacteremia (SAB) carries a 30-day mortality rate of 15% to 30%. The traditional “complicated” or “uncomplicated” classification may miss initially occult metastatic infection or expose patients to unnecessarily prolonged antibiotics.

The first installment of new consensus guidance from the Infectious Diseases Society of America (IDSA) and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) replaces the binary classification of SAB with a stepwise, dynamic framework. Adults are initially categorized as low or increased risk based on their presentation, follow-up cultures, echocardiography, and repeated clinical assessment.

Three factors consistently signal increased risk: community-onset SAB, a positive blood culture obtained at least 48 hours after the first positive culture, and an intracardiac device. Other concerning features include predisposing valve disease, injection drug use, an endovascular graft, SAB within 90 days, embolic events, multiple noncontiguous infection sites, an unknown source, or symptoms suggesting a deep focus.

For adults, obtain at least 2 sets of follow-up blood cultures at 48 hours after the first positive culture, then 1 or 2 sets every 24 to 48 hours until clearance. The clearance date generally starts the treatment clock; promptly remove implicated central venous catheters and reassess source control if bacteremia persists.

Perform transthoracic echocardiography in all adults. If TTE is negative, obtain transesophageal echocardiography when major endocarditis risk features are present; TEE may be omitted after a good-quality negative TTE in patients without those features.

For increased-risk adults whose source remains unknown after cultures, echocardiography, and symptom-directed imaging, consider whole-body imaging such as FDG-PET/CT or a targeted combination of imaging modalities. Infectious diseases consultation is strongly encouraged.

Treat low-risk adults without identified deep-seated or metastatic infection for 14 days. Increased-risk adults may also receive 14 days if a tailored evaluation is negative and signs and symptoms resolve, but consider longer therapy for prolonged bacteremia, incomplete or indeterminate testing, retained prosthetic material, or persistent concern for occult infection.

All children with SAB should be assessed for a deep focus because evidence is insufficient to define a pediatric low-risk group. TTE is targeted to structural heart disease, prolonged bacteremia, or suspected endocarditis; TEE and whole-body imaging are reserved for selected cases, and 14 days is suggested when no deep focus is found.

“It is important for the clinician to identify risk factors for disease severity and infectious complications, which may be inapparent at first,” said co-chair Henry F. Chambers, MD. The panel calls the statements a starting point and notes that prospective validation and real-world outcome studies remain necessary.

Source: Liu C, et al. (2026 Sep 9) IDSA/ESCMID Consensus Statements on Staphylococcus aureus Bacteremia: Risk Stratification, Diagnostic Evaluation, and Management of Adults and Children. Infectious Diseases Society of America