Staphylococcus aureus bacteremia
From IDWiki
Background
Classification
- Community-onset: positive blood culture obtained within 48 hours of presentation
- Nosocomial: positive blood culture obtained after 48 hours of presentation
Etiology
- IVDU
- Poor dentition
- Dental work
Clinical Manifestations
- Often non-specific fevers and chills, diagnosed on blood cultures
- May have back pain unrelated to spinal osteomyelitis
- May present with focus of metastatic disease
Investigations
- Repeat blood cultures every 24 to 48 hours until negative
- Transthoracic echo (TTE) or transesophageal echo (TEE)
- A modern TTE that is good-quality and shows normal valves is quite good, though TEE is still better
- TEE is strongly suggested in certain cases:
- Cerebral or peripheral emboli
- Meningitis
- Implantable cardiac device or prosthetic heart valve
- Prior infective endocarditis
- Native valve disease
- Injection drug use
- Persistent bacteremia beyond 72 hours
- Can also use PREDICT score to decide if they need TEE
Management
- Infectious diseases consultation
- Must rule out endocarditis! TTE, followed by TEE if suspicion remains high (see PREDICT score)
- Low risk for endocarditis (no TEE) if all of the following:
- No intracardiac device
- Sterile follow-up blood cultures within 4 days from the initial set
- No hemodialysis
- Nosocomial acquisition
- Absence of secondary foci
- No clinical signs of endocarditis
- Uncomplicated if all of the following:
- Endocarditis is excluded
- No implanted prostheses
- Blood cultures clear by 2-4 days
- Defervesces within 72 hours
- No evidence of metastases
- +/- identified source has been removed
- Low risk for endocarditis (no TEE) if all of the following:
- Two-week course acceptable if uncomplicated, otherwise 4-6 weeks
- MSSA: cloxacillin 2g IV q4h for 2 weeks (cefazolin as an alternative)
- MRSA: vancomycin 1g IV q12h for 2 weeks
- Adjust based on serum trough before every fourth dose
- Target trough 15-20
Prognosis
- Mortality 20-50% at 30 days, 60% at 1 year
- Mortality halved by ID consult
- Prognosis worse with
- Increased age
- Female sex
- Pneumonia or source unknown
- Dementia
- Increasing comorbidities
- Shock at time of presentation
- Institutionalized patient
Further Reading
References
- ^ Anthony D. Bai, Carson KL. Lo, Adam S. Komorowski, Mallika Suresh, Kevin Guo, Akhil Garg, Pranav Tandon, Julien Senecal, Olivier Del Corpo, Isabella Stefanova, Clare Fogarty, Guillaume Butler-Laporte, Emily G. McDonald, Matthew P. Cheng, Andrew M. Morris, Mark Loeb, Todd C. Lee. Staphylococcus aureus bacteremia mortality: A systematic review and meta-analysis. Clinical Microbiology and Infection. 2022. doi:10.1016/j.cmi.2022.03.015.
- ^ Sarah Tubiana, Xavier Duval, François Alla, Christine Selton-Suty, Pierre Tattevin, François Delahaye, Lionel Piroth, Catherine Chirouze, Jean-Philippe Lavigne, Marie-Line Erpelding, Bruno Hoen, François Vandenesch, Bernard Iung, Vincent Le Moing. The VIRSTA score, a prediction score to estimate risk of infective endocarditis and determine priority for echocardiography in patients with Staphylococcus aureus bacteremia. Journal of Infection. 2016;72(5):544-553. doi:10.1016/j.jinf.2016.02.003.
- ^ Thomas W van der Vaart, Jan M Prins, Robin Soetekouw, Gitte van Twillert, Jan Veenstra, Bjorn L Herpers, Wouter Rozemeijer, Rogier R Jansen, Marc J M Bonten, Jan T M van der Meer. Prediction Rules for Ruling Out Endocarditis in Patients With Staphylococcus aureus Bacteremia. Clinical Infectious Diseases. 2021;74(8):1442-1449. doi:10.1093/cid/ciab632.
