Septic Arthritis of Native Joints Organism-Specific Therapy 

Updated: Oct 02, 2020
Author: John L Brusch, MD, FACP; Chief Editor: Michael Stuart Bronze, MD 

Specific Organisms and Therapeutic Regimens

Organism-specific regimens for septic arthritis of native joints are provided below, including those for methicillin-sensitive and methicillin-resistant Staphylococcus aureus, streptococci, gram-negative rods, Pseudomonas, and Neisseria gonorrhoeae.[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Oral antibiotics should be considered for treating septic arthritis. A recent study of septic arthritis involving native and prosthetic joints found that orally administered antibiotics started within 7 days of instituting IV therapy were noninferior to antibiotics administered intravenously through the entire therapeutic course (13% and 15%, respectively). The primary pathogens included S aureus (38%), coagulase-negative staphylococci (27%), and Streptococcus species (15%) Sixty-one percent had prosthetic-related infections. Rifampin was given to 41% of the IV group and 56% of the PO group. For initial oral treatment, the pathogen must be sensitive to antibiotics that have superior GI absorption, and the patient should have no major suppurative complications that would require surgery. These results need to be confirmed by follow-up studies. At minimum, this study may be useful in justifying switchover to PO antibiotics earlier than has been done in the past.[11, 12]

Methicillin-sensitive Staphylococcus aureus (MSSA)

See the list below:

  • Nafcillin 2 g IV q4h for ≥ 3wk or

  • Oxacillin 2 g IV q4h for ≥ 3wk or

  • Cefazolin 2 g IV q8h for ≥ 3wk or

  • Ceftriaxone 1 g IV q24h for ≥ 3wk or

  • Vancomycin 15 mg/kg q12h for ≥ 3wk (if patient is allergic to penicillin)

Methicillin-resistant S aureus (MRSA)

See the list below:

  • Vancomycin 15 mg/kg q12h for ≥ 3wk or

  • Linezolid 600 mg IV or PO q12h for ≥ 3wk or

  • Daptomycin 6 mg/kg IV q24h for ≥ 3wk

Penicillin-sensitive streptococci (minimal inhibitory concentration [MIC] < 4 µg/mL)

See the list below:

  • Ampicillin 2 g IV q4h for ≥ 2wk or

  • Ceftriaxone 1 g IV q24h for ≥ 2wk or

  • Vancomycin 15 mg/kg q12h for ≥ 2wk

Penicillin-resistant Streptococcus pneumoniae (MIC ≥ 4 µg/mL)

See the list below:

  • Ceftriaxone 1-2 g IV q12h for ≥ 2wk or

  • Vancomycin 15 mg/kg q12h for ≥ 2wk or

  • Levofloxacin 750 mg IV or PO q24h for ≥ 2wk

Gram-negative rods (other than Pseudomonas)

See the list below:

  • Ceftriaxone 1 g IV q24h for ≥ 3wk or

  • Ciprofloxacin 400 mg IV or 500 mg PO q12h for ≥ 3wk or

  • Levofloxacin 500 mg IV or PO q24h for ≥ 3wk

Pseudomonas aeruginosa

See the list below:

  • Cefepime 2 g IV q8h plus (gentamicin or tobramycin 5 mg/kg IV q24h for ≥ 3wk) or

  • Piperacillin-tazobactam 3.375-4.5 g IV q6h plus (gentamicin or tobramycin 5 mg/kg IV q24h for ≥ 3wk) or

  • Aztreonam 1-2 g IV q8h plus (gentamicin or tobramycin 5 mg/kg IV q24h for ≥ 3wk)

Neisseria gonorrhoeae

See the list below:

  • Ceftriaxone 1 g IV or IM q24h for 2wk or
  • Cefixime 400 mg PO BID for 2wk or
  • Cefpodoxime 400 mg PO BID for 2wk or
  • Ciprofloxacin 400 mg IV or 500 mg PO q12h for 2wk (if organism is susceptible)

Special considerations

See the list below:

  • Examination of the joint fluid is the key diagnostic test; it typically shows some marked leukocytosis, often > 50,000/µL; glucose is low with no crystals; the Gram stain is positive in < 50% of cases
  • If the Gram stain is negative and crystals are apparent, one may withhold antibiotics and treat for crystalline arthritis unless there is a significant potential source of bacteremia, such as a urinary tract infection. In such situations, the measurement of serum calcitonin may be helpful to document infection. It should not be used to exclude infection. [12]
  • In patients in whom it is difficult maintain an adequate trough level of vancomycin when treating MSSA or MRSA infection (15-20 mcg/mL), consideration should be given to the use of linezolid or daptomycin.
  • Because of its once-weekly dosing regimen, dalbavancin should be considered in patients receiving prolonged antibiotic therapy for susceptible organisms, including all non-enterococcal streptococci, MSSA, MRSA, vancomycin-intermediate S aureus (VISA), CoNS, and vancomycin-sensitive enterococci. [13]
  • Gonococcal arthritis has 2 major types of presentation: (1) the combination of pustular skin lesions, tenosynovitis, and arthralgias without direct joint space involvement; and (2) a typical septic joint without skin lesions
  • Because of the low recovery rate of gonococci from infected joints (25% of cases), potential exposed sites (pharynx, rectum, cervix, urethra) should be cultured in addition to the joint fluid; urine nucleic acid amplification testing (NAAT) can also be performed
  • Blood cultures should be obtained in all patients with suspected joint infection
  • Plain radiography may detect evidence of underlying osteomyelitis or periarticular osteomyelitis caused by extension of the joint infection
  • If joint fluid reaccumulates after the initial aspiration, repeated aspirations should be performed
  • Intra-articular administration of antibiotics is unnecessary
  • If the joint does not show clinical improvement within 72h (or if cultures remain positive after 5d), surgical drainage should be considered, the joint fluid should be reexamined for crystals, and other diagnoses should be considered (eg, Lyme or reactive arthritis)
  • All sexual contacts of patients with gonococcal arthritis should be treated with a single dose of ceftriaxone 125 mg IM or of cefixime 400 mg PO

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