Bone & Joint Infections without Hardware

Staphylococcus aureus 

Group A streptococcus 

Kingella kingae in children < 3 years 

------------------------ 

Lyme arthritis is a distinct diagnosis separate from septic arthritis and should be considered in the differential diagnosis for septic arthritis - see subsection below for features that should prompt consideration  

Clinically stable:  

Cefazolin 50 mg/kg/dose (max 2000 mg/dose) IV q8h  

------------------------ 

Severely ill (hemodynamic instability, multiple sites involved, or known positive blood culture for gram- positive organism (while awaiting initial ID and susceptibility):  

Cefazolin 50 mg/kg/dose (max 2000 mg/dose) IV q8h  

AND  

Vancomycin  

(follow link for dosing & monitoring)  

Consult ID for therapy selection if blood culture is positive for a gram-negative organism 

Penicillin or cephalosporin allergy with higher risk for allergic reaction or, clinically stable with history of documented MRSA infection or carriage within the last 6 months 

Please confirm clindamycin susceptibility if prior cultures are available, tailor antibiotics to past susceptibility: 

Clindamycin 13 mg/kg/dose (max 900 mg/dose) IV q8h 

Penicillin or cephalosporin allergy with higher risk for allergic reaction, severely ill (hemodynamic instability or rapid local progression) or known positive blood culture for gram-positive organism (while awaiting initial ID and susceptibility):  

Consult ID 

ID and Orthopedic Surgery consults recommended 

Surgical evaluation is considered urgent for all patients with suspected septic arthritis and is particularly time-sensitive for septic arthritis of the hip, knee or shoulder 

At initial evaluation, send ESR, CRP and blood culture  

Joint aspirate should be performed before antibiotics unless patient is clinically unstable or has known bacteremia (send cell count, routine culture, hold “universal microbial DNA” from fluid) 

If cultures are positive, use results of preliminary diagnostic tests to target therapy 

Duration: Uncomplicated septic arthritis is usually treated for 2-3 weeks, guided by follow-up assessments, with minimum 3 weeks for infection due to S. aureus 

Lyme arthritis 

Distinguishing features of Lyme arthritis of the knee from septic arthritis of the knee in an endemic area include:  

Peripheral blood absolute neutrophil count  <10,000 cells/mm3

AND

ESR < 40 mm/hr 

Additional suggestive features:  
Lower synovial fluid WBC, lack of fever or systemic illness, history of residence or travel to endemic area, greater ability to bear weight 
 
Diagnostic testing: 2 step serology - Lyme EIA, reflex to IgG Western blot if EIA is positive (positive IgM Western blot with negative IgG Western blot is not consistent with this diagnosis) 

Age >=8years: 

Doxycycline 2.2 mg/kg/dose (max 100mg/dose) PO bid  

Age <8 years: Amoxicillin 16.7 mg/kg/dose (max 500mg/dose) PO tid 

ID consult recommended  
 
Lyme arthritis is managed without surgery and does not always necessitate invasive evaluation (joint aspirate); Orthopedic Surgery should be consulted if septic arthritis is also being considered  

Duration: 28 days, with follow-up assessment 

Note that treatment recommendation and duration is specific to Lyme arthritis and not applicable to other manifestations of Lyme disease 

Staphylococcus aureus 

Group A streptococcus 

Kingella kingae in children < 3 years 

Clinically stable (see note in Comments column about waiting for cultures if surgical debridement planned):  

Cefazolin 50 mg/kg/dose (max 2000 mg/dose) IV q8h  

------------------------ 

Severely ill (hemodynamic instability, multiple sites involved, or rapid local progression) or known positive blood culture for gram-positive organism (while awaiting initial ID and susceptibility): 

Cefazolin 50 mg/kg/dose (max 2000 mg/dose) IV q8h  

AND 

Vancomycin  

(follow link for dosing & monitoring) 

Consult ID for therapy selection if blood culture is positive for a gram-negative organism 

Penicillin or cephalosporin allergy with higher risk for allergic reaction, or history of documented MRSA infection or carriage within the last 6 months  

(Please confirm clindamycin susceptibility if prior cultures are available, tailor antibiotics to past susceptibility): 

Clindamycin 13 mg/kg/dose (max 900 mg/dose) IV q8h  

Penicillin or cephalosporin allergy with higher risk for allergic reaction, severely ill (hemodynamic instability or rapid local progression) or known positive blood culture for gram-positive organism (while awaiting initial ID and susceptibility): 

Consult ID 

ID and Orthopedic Surgery consults recommended 

At initial evaluation, send ESR, CRP and blood culture 

Discuss with Orthopedic Surgery before starting antibiotics if the patient is hemodynamically stable. If surgical debridement is planned, may prefer to hold antibiotics until after operative cultures are sent 

Therapy should be tailored to the identified organism. Change from IV to PO and total duration of therapy should be determined in consultation with ID based on the patient's clinical course 

If cultures are positive, use results of preliminary diagnostic tests to target therapy 

Duration: Uncomplicated acute hematogenous osteomyelitis is usually treated for 4-6 weeks, guided by follow-up assessments 

S. aureus

Streptococci (anaerobic or aerobic)

E.coli

If patient is stable, has negative blood cultures, and is without epidural abscess, withhold antibiotics until bone biopsy and consult ID

Ceftriaxone 2g IV q24h

PLUS

Vancomycin

If patient is stable, has negative blood cultures, and is without epidural abscess, withhold antibiotics until bone biopsy and consult ID

For severe PCN allergy:

Aztreonam 2g IV q8h

PLUS

S. aureus

Coagulase-negative staphylococci

Streptococcus spp.

Enterococcus

Gram-positive rods

Enterobacteriaceae (rarely)

If patient is stable, withhold antibiotics until cultures are taken

Call ID for treatment assistance

Non-vertebral osteomyelitis
Presumed hematogenous source or contiguous without vascular insufficiency (no hardware in place)

S. aureus
Streptococci
GNRs (rarely)

If patient is stable and has negative blood cultures, withhold antibiotics until bone biopsy and consult ID

Vancomycin

If S. aureus is methicillin-susceptible then cefazolin 2g IV q8h or nafcillin 2g IV q4h are the antibiotics of choice

Non-vertebral osteomyelitis

S. aureus Enterobacteriaceae Anaerobes

Obtain bone biopsy to determine microbiologic cause prior to initiation of antimicrobial therapy if patient clinically stable and has negative blood cultures

Vancomycin

PLUS

Ceftriaxone

Obtain bone biopsy to determine microbiologic cause prior to initiation of antimicrobial therapy if patient clinically stable and has negative blood cultures

For severe PCN allergy: Vancomycin

PLUS ONE OF:

Ciprofloxacin

OR

Aztreonam

WITH

Metronidazole (if patient critically ill)

Consider Pseudomonal coverage with Piperacillin-Tazobactam or Cefepime in patients with the following risk factors:

• Macerated ulcer or warm (tropical) climate

Include anaerobic coverage with piperacillin-tazobactam in necrotic or gas forming infections (see SSTI guidance for NSTI management)

Other organisms are possible, esp. with hardware-microbiologic diagnosis and ID consultation recommended

Once stable, switch to oral antibiotics based on susceptibility results

Septic Arthritis (no hardware in place)

S. aureus
Streptococcus spp.
N. gonorrhoeae
Enterobacteriaceae (rarely)

Vancomycin
PLUS
Ceftriaxone 2g IV daily if at risk for gonococcus or GNR (IDU, immunocompromised, elderly) or Gram stain shows gram-negative organisms

For severe PCN allergy:
Vancomycin
PLUS:
Aztreonam
If N. gonorrhoeae suspected, please consult ID or ID pharmacy for alternate treatment recommendations

Gram stain recommended to guide therapy

Narrow coverage to microbiologically confirmed pathogens.