Staphylococcus aureus bacteremia: Difference between revisions
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Staphylococcus aureus bacteremia
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===Etiology=== |
===Etiology=== |
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*[[Skin and soft tissue infection]], including infections of a [[decubitus ulcer]] in hospitalized patients |
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*IVDU |
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*[[Infective endocarditis]] |
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*[[Osteomyelitis]] |
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*[[Septic arthritis]] |
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*[[Septic thrombophlebitis]] |
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*[[Central line-associated bloodstream infection]] |
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*Injection drug use |
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*Poor dentition |
*Poor dentition |
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*Dental work |
*Dental work |
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Latest revision as of 12:43, 27 September 2024
Background
Classification
- Community-onset: positive blood culture obtained within 48 hours of presentation
- Nosocomial: positive blood culture obtained after 48 hours of presentation
Etiology
- Skin and soft tissue infection, including infections of a decubitus ulcer in hospitalized patients
- Infective endocarditis
- Osteomyelitis
- Septic arthritis
- Septic thrombophlebitis
- Central line-associated bloodstream infection
- Injection drug use
- 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
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 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
- Low risk for endocarditis (no TEE) if all of the following:
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
- Standard of care is still currently IV therapy for the duration, though there is emerging evidence for treating a number of deep-seated infections (osteomyelitis, endocarditis) with early oral antibiotics, including infections caused by Staphylococcus aureus
Dosing
Penicillin- or Methicillin-Susceptible Strains
| Antibiotic | Renal Function | Standard Dose | Critical Illness Dose† |
|---|---|---|---|
| benzylpenicillin (pen G) | eGFR >50 | 1.8 g (3 MU) q4h | 2.4 g (4 MU) q4h |
| eGFR 10-50 | 1.8 g (3 MU) q6h | 1.8 g (3 MU) q4h | |
| eGFR <10 | 1.8 g (3 MU) load, then 1.2 g (2 MU) q8h | 2.4 g load, then 1.2 g (2 MU) q6h | |
| CRRT | 1.2 g (2 MU) q6h | 1.8 g (3 MU) q6h | |
| flucloxacillin | eGFR ≥10 | 2 g q6h | 2 g q4h |
| eGFR <10 | 1 g q6h | 1 g q4h | |
| CRRT | 2 g q6h | 2 g q6h | |
| cloxacillin | any | 2 g q4h | 2 g q4h |
| cefazolin | eGFR >40 | 2 g q8h | 2 g q6h |
| eGFR 20-40 | 2 g q12h | 2 g q12h | |
| eGFR <20 | 1 g q24h | 1 g q24h | |
| CRRT | 2 g q12h | 2 g q12h |
*† Critical illness dosing should be used for patients with septic shock, admitted to ICU, with endocarditis, or with CNS infection (excluding spinal epidural abscess)
- May be decreased to standard dosing once no longer requiring mechanical ventilation or vasopressors for at least 24 hours
Methicillin-Resistant Strains
Vancomycin Dosing
- Vancomycin dosing may follow local guidelines
- Includes loading dose of 25 mg/kg (max 3 g) if considered appropriate by the physician, then maintenance dosing at 15-20 mg/kg q12h, adjusted to target AUC 400-600 mg h/L or trough 10-20 mg/L
Daptomycin Dosing
| Renal Function | Suggested Dose |
|---|---|
| eGFR >50 | 8-10 mg/kg q24h |
| eGFR 11-50 | 6-8 mg/kg q24h |
| eGFR ≤10 | 8 mg/kg q48h |
| CRRT | 8 mg/kg q48h |
| HD | 8 mg/kg q48h, given after dialysis |
Adjunctive Cefazolin Dosing
| Renal Function | Suggested Dose |
|---|---|
| CrCl >40 | 2 g q8h |
| CrCl 20-40 | 2 g q12h |
| CrCl <20 | 1 g q24h |
| CRRT | 1 g q8h or 2 g q12h |
| HD | 2 g after each dialysis session |
Early Oral Switch
| Silo | IV Antibiotic | Suggested First-Line | Suggested Second-Line (ordered) |
|---|---|---|---|
| PSSA | benzylpenicillin | amoxicillin | flucloxacillin/dicloxacillin, cefalexin/cefadroxil, linezolid |
| (flu)cloxacillin | flucloxacillin/dicloxacillin | amoxicillin, cefalexin/cefadroxil, linezolid | |
| MSSA | (flu)cloxacillin | flucloxacillin/dicloxacillin | cefalexin/cefadroxil, linezolid |
| cefazolin | cefalexin/cefadroxil | flucloxacillin/dicloxacillin, linezolid | |
| MRSA | vancomycin/daptomycin | linezolid | fluoroquinolone+rifampin, TMP-SMX, fusidic acid+rifampin |
| vancomycin/daptomycin+cefazolin | linezolid | fluoroquinolone+rifampin, TMP-SMX, fusidic acid+rifampin |
| Antibiotic | Renal Function | Suggested Dose | Notes |
|---|---|---|---|
| amoxicillin | normal | 1 g q6h ± probenecid | |
| CrCl 10-30 | 1 g q8h | ||
| CrCl <10 | 1 g q12h | ||
| CRRT | 1 g q8h | ||
| HD/PD | 1 g q12h | ||
| cefadroxil | normal | 1 g q12h | |
| CrCl 10-50 | 1 g then 500 mg q12h | ||
| CrCl <10 | 1 g then 500 mg q36h | ||
| CRRT | 1 g then 500 mg q12h | ||
| HD | 1 g then 1 g post-HD | ||
| PD | 500 mg q24h | ||
| cefalexin | normal | 1 g q6h ± probenecid | |
| CrCl <10 | 1 g q12h | ||
| CRRT | 1 g q6h | ||
| HD/PD | 1 g q12h | ||
| ciprofloxacin | normal | 750 mg q12h | |
| CrCl <30 | 750 mg q24h | ||
| CRRT | 250-500 mg q12h | ||
| HD/PD | 750 mg q24h | ||
| clindamycin | any | 450 mg q8h | |
| cloxacillin | any | 1 g q6h | |
| dicloxacillin | normal | 1 g q6h | |
| CrCl <10 | 1 g q8h | ||
| CRRT | 1 g q6h | ||
| HD/PD | 1 g q8h | ||
| doxycycline | any | 100 mg q12h | |
| flucloxacillin | normal | 1 g q6h | |
| CrCl <10 | 1 g q8h | ||
| CRRT | 1 g q6h | ||
| HD/PD | 1 g q8h | ||
| fusidic acid | any | 500 mg q24h | |
| levofloxacin | normal | 750 mg q24h | |
| CrCl 20-49 | 750 mg q48h | ||
| CrCl <20 | 750 mg then 500 mg q48h | ||
| CRRT | 250 mg q24h | ||
| HD/PD | 750 mg then 500 mg q48h | ||
| linezolid | normal | 600 mg q12h | |
| CrCl <10 | 600 mg q24h | ||
| CRRT | 600 mg q12h | ||
| HD/PD | 600 mg q24h | ||
| moxifloxacin | any | 400 mg daily | |
| probenecid | CrCl ≥60 | 500 mg with each dose of β-lactam | |
| CrCl 30-60 | 250 mg with each dose of β-lactam | ||
| CrCl <30 | avoid use | ||
| rifampin | any (weight <60kg) | 600 mg daily | |
| any (weight >60 kg) | 900 mg daily | ||
| tedizolid | any | 200 mg q24h | |
| TMP-SMX | normal | 2 DS q12h or 1 DS q8h | |
| CrCl 26-50 | normal dose for 14 days then 1 DS q12h | ||
| CrCl 15-25 | normal dose for 3 days then 2 DS q24h | ||
| CrCl <15 | avoid use |
Adjunctive Clindamycin
- Clindamycin 600 mg IV q8h for 5 days as adjunctive therapy regardless of clindamycin susceptibility
- Alternative is 450 mg p.o. q8h for 5 days, though preference for IV
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.
