View source for Staphylococcus aureus bacteremia

==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:
***[[Embolic stroke|Cerebral]] or peripheral emboli
***[[Meningitis]]
***[[Cardiovascular implantable electronic device infection|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
*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 of [[S. aureus]]
**Absence of secondary foci
**No clinical signs of endocarditis
*Uncomplicated if:
**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
*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==

{{DISPLAYTITLE:''Staphylococcus aureus'' bacteremia}}
[[Category:Endovascular infections]]