Staphylococcus aureus bacteremia: Difference between revisions

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Staphylococcus aureus bacteremia
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*May have back pain unrelated to spinal osteomyelitis
 
*May have back pain unrelated to spinal osteomyelitis
 
*May present with focus of metastatic disease
 
*May present with focus of metastatic disease
  +
 
===Prognosis===
  +
 
*Associated with about 30% mortality[[CiteRef::bai2022st]]
 
*Associated with about 30% mortality[[CiteRef::bai2022st]]
 
*Mortality halved by ID consult in observational studies
 
*Prognosis worse with
 
**Increased age
 
**Female sex
 
**[[Pneumonia]] or source unknown
 
**[[Dementia]]
 
**Increasing comorbidities
 
**[[Shock]] at time of presentation
 
**Institutionalized patient
   
 
==Investigations==
 
==Investigations==
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*Infectious diseases consultation
 
*Infectious diseases consultation
  +
*Must rule out endocarditis! TTE, followed by TEE if suspicion remains high (see [[PREDICT score]])
 
  +
=== Echocardiography ===
 
*Must rule out endocarditis! TTE, followed by TEE if suspicion remains high (see [[VIRSTA score]])
 
**Low risk for endocarditis (no TEE) if all of the following:
 
**Low risk for endocarditis (no TEE) if all of the following:
 
***No intracardiac device
 
***No intracardiac device
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***No evidence of metastases
 
***No evidence of metastases
 
***+/- identified source has been removed
 
***+/- identified source has been removed
  +
*Two-week course acceptable if uncomplicated, otherwise 4-6 weeks
 
  +
=== Antimicrobial Therapy ===
 
*Two-week course acceptable if uncomplicated, otherwise 4-6 weeks based on clinical course and underlying foci of infection
 
*MSSA: [[cloxacillin]] 2g IV q4h for 2 weeks ([[cefazolin]] as an alternative)
 
*MSSA: [[cloxacillin]] 2g IV q4h for 2 weeks ([[cefazolin]] as an alternative)
 
*MRSA: [[vancomycin]] 1g IV q12h for 2 weeks
 
*MRSA: [[vancomycin]] 1g IV q12h for 2 weeks
 
**Adjust based on serum trough before every fourth dose
 
**Adjust based on serum trough before every fourth dose
 
**Target trough 15-20
 
**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==
 
==Further Reading==

Revision as of 10:05, 2 May 2022

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

Prognosis

  • Associated with about 30% mortality1
  • Mortality halved by ID consult in observational studies
  • Prognosis worse with
    • Increased age
    • Female sex
    • Pneumonia or source unknown
    • Dementia
    • Increasing comorbidities
    • Shock at time of presentation
    • Institutionalized patient

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:
    • Can also use VIRSTA score to decide if they need TEE2
      • Highest sensitivity (~99%), though specificity only 35%
      • The high sensitivity gives very high negative predictive value of ~99%
      • Likely preferred to others like the PREDICT score, which has lower sensitivity though higher specificity3

Management

  • Infectious diseases consultation

Echocardiography

  • Must rule out endocarditis! TTE, followed by TEE if suspicion remains high (see VIRSTA 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

Antimicrobial Therapy

  • Two-week course acceptable if uncomplicated, otherwise 4-6 weeks based on clinical course and underlying foci of infection
  • 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

Further Reading

References

  1. ^  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.
  2. ^  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.
  3. ^  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.