Antimicrobial Stewardship (AMS)

• Acute, unilateral, spreading area of erythema
• Characterized by heat, pain/tenderness, and swelling
• Superficial skin swabs are not recommended for diagnosis
• Important to exclude conditions with similar signs and symptoms:
  • Charcot foot (neuropathic arthropathy)
  • Deep vein thrombosis
  • Erythema migrans (Lyme disease)
  • Gout
  • Lymphedema
  • Venous stasis dermatitis
• Early assessment for red flag symptoms is recommended to rapidly identify complicated skin and soft tissue infection:
  • Animal or human bites
  • Immunosuppression, including  asplenia
  • Loss of sensation in the affected area
  • Necrosis, hemorrhagic bullae, crepitus
  • Rapid onset of severe pain, especially if out of proportion to clinical findings
  • Rapid progression despite antibiotic use
  • Significant periorbital involvement
• Blood cultures are recommended if systemic symptoms are present

Last reviewed June 2020

• Elevation of the affected area (above level of heart) for majority of the day is essential
• Skin should be hydrated to avoid dryness and cracking, avoiding interdigital maceration
• Treat underlying predisposing conditions (e.g., tinea pedis)
• Assess vascular supply if suspicion of arterial insufficiency (e.g., Ankle Brachial Index)
• Long-term management of chronic venous insufficiency and lymphedema with compression

Last reviewed June 2020

• Various severity classification schemes have been developed to assist in management.
• None of these schemes have been validated and they are meant for guidance only. For example, not every immunocompromised patient has a severe cellulitis.

*2 or more of: Temp greater than 38 °C or less than 36 °C; respiratory rate greater than 24 breaths/min; heart rate greater than 90 bpm; WBC greater than 12 or less than 4 x 10⁹ /L

Last reviewed June 2020

•   Antimicrobial choice and route of administration should be guided by severity of illness

 * Higher dose (q12h) preferred for obese patients, significant inflammation, or bacteremic
1. 1st line in patients with IgE mediated penicillin allergy 
2.  Can transition to oral therapy when systemic symptoms resolved for at least 24 hours 
3.  Dose adjustment required for renal dysfunction; refer to NSHA Spectrum app for guidance

Last reviewed June 2020

Usually 5-7 days

Last reviewed June 2020

• Erythema and extension often progress in first 24 hours of treatment. This is not considered a treatment failure.
• Systemic symptoms usually improve in 24-48 hours if on appropriate treatment
• Residual skin discoloration  or edema may be present at end of antibiotic course and is not a reason to prolong antibiotics. Full skin healing may take weeks while limb edema can persist for months after signs of infection resolve.

Last reviewed June 2020

1. Antibiotics Why and Why Not 2018 Dalhousie CPD Academic Detailing Service, November 2018.

2. Stevens DL, Bisno AL, Chambers HF, et al. Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America. Clinical Infectious Diseases 2014;59(2): e10–52.

3. Raff AB, Kroshinsky D. Clinical Review and Education: Cellulitis. JAMA. 2016;316(3):325-337.

Last reviewed June 2020

• Two or more local inflammatory symptoms: erythema, warmth, swelling, tenderness or pain, or purulent secretions
• May also include secondary signs (friable or discolored granulation tissue, undermining of wound edges, foul odor, tissues necrosis)
• The presence of systemic symptoms (e.g., fever, rigors, hypotension) or acute change in the foot (e.g., swelling, pain, increasing drainage, crepitus) suggests a life- or limb-threatening infection

Last reviewed July 2020

• Plain radiographs for bony abnormalities, soft tissue gas, and radio-opaque foreign bodies
• Osteomyelitis is a clinical diagnosis; determine severity and depth of the infection
  • Seeing or probing-to-bone in the setting of a clinical picture of infection suggests osteomyelitis
  • More advanced imaging may be required to assess extent of infection for surgical purposes; should consult an expert in managing bone and joint infections
  • Bone scan is not specific, and rarely useful
• Send appropriately obtained specimen prior to starting empiric therapy
  • Deep tissue/bone biopsy or curettage after wound has been cleansed and debrided
  •  Avoid swab specimens of superficial ulcer, especially of inadequately debrided wounds
• Urgent orthopedic surgery consult if DFI accompanied by gas, abscess, or necrotizing fasciitis

Last reviewed July 2020

• Vascular assessment: check for peripheral pulses and necrotic tissue
  • Vascular surgery consult if ischemia or absent pulses
  • Ankle-brachial index (ABI) for non-urgent vascular assessment
• Diabetes optimization
• Pressure offloading of the affected area
  • consult the pedorthist
• Wound care
  • consult the wound care nurse 
• Consider ID consult for moderate to severe infections

Last reviewed July 2020

Last reviewed July 2020

TREATMENT    

• Cellulitis without ulcer – see cellulitis guideline 
• Non-acute, dry ulcers without signs of infection – No antibiotics needed urgently
• Osteomyelitis treated with radical resection and no residual infection – short course antimicrobial therapy for 2-5 days
• Severe infection, septic arthritis, osteomyelitis: consult a specialist for recommendations

a. requires dose adjustment in renal dysfunction. Refer to NS health Firstline app

b. can be used in patients with IgE mediated penicillin allergy

c. 2 g dose of ceftriaxone should be used for treating septic arthritis or osteomyelitis, otherwise 1 g is sufficient

Last reviewed June 2023

1. Lipsky BA, Berendt AR, Cornia PB, Pile JC, et al. 2012 Infectious Diseases Society of America Clinical Practice Guideline for the Diagnosis and Treatment of Diabetic Foot Infections. Clin Infect Dis. 2012 Jun 15;54(12):132-173.

2. Grigoropoulou P, Eleftheriadou I, Jude EB, Tentolouris N. Diabetic Foot Infections: An Update in Diagnosis and Management. Curr Diab Rep 2017 17(3): doi: 10.1007/s11892-017-0831-1.

3. Antimicrobial Stewardship Treatment Guidelines for Common Infections. Vancouver General Hospital University of British Columbia. (March 2016)

Last reviewed July 2020

• Diagnosis usually made by clinical presentation and reported history of bite
• Wound cultures are not usually possible
• Assess tetanus immunization status and provide prophylaxis as needed
  • Bites are considered tetanus-prone wounds
• Assess rabies risk – If concern regarding rabies exposure please contact NS Public Health or the Medical Officer of Health on call (902-473-2222) as soon as suspected
• Blood cultures should be obtained in patients with fever or other signs of systemic infection and patients who are immunosuppressed

Last reviewed April 2022

• Initial thorough cleaning of the wound with copious amounts of soap and water is recommended 
• Surgical consult as appropriate 

Last reviewed April 2022

• The decision to give prophylactic antibiotics should be based on the following wound severity and host immune factors:
  • Immunocompromised
  • Functional or anatomical splenectomy
  • Advanced liver disease
  • Pre-existing or resultant edema of the affected area
  • Injury to the face, hands, genitalia or feet 
  • Wounds involving the periosteum or joint capsule
  • Wounds that require primary wound closure
• Amoxicillin-clavulanate 875/125 mg PO BID 

Last reviewed April 2022

• Amoxicillin-clavulanate 875/125mg PO BID 
• If IV therapy required:
  • Ceftriaxone 1g IV daily + metronidazole 500mg PO/IV BID or
  • Amoxicillin-clavulanate 2000mg/200mg IV q12h

Last updated April 2022

• Cefuroxime 500mg PO BID + metronidazole 500mg PO BID
• Doxycycline 100mg PO BID + metronidazole 500mg PO BID 
• Levofloxacin 750mg PO/IV daily + metronidazole 500mg PO/IV BID

Last updated April 2022

• Prophylaxis: 3-5 days 
• Treatment: 5-10 days tailored to clinical response
• Longer duration for infection involving bone or joint

Last reviewed April 2022

• Risk of transmitting blood-borne pathogens with clenched fist and other human hand bite wounds
• Macrolides should be avoided in animal bites as they have poor activity against most pathogens
• Pasteurella spp, Capnocytophaga spp, and Eikenella are resistant to first generation cephalosporins such as cephalexin and cefazolin

Last reviewed April 2022

1. Infectious Diseases Society of America. (2014). Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America. Clinical Infectious Diseases, 59(2), e10–e52. https://doi.org/10.1093/cid/ciu296

Last reviewed April 2022

• The following signs may not be apparent on initial assessment so frequent reassessment should be performed.
• Signs of systemic toxicity such as fever, hypotension, leukocytosis, or acute renal failure
• Severe pain and tenderness out of proportion to exam (often one of the earliest signs)
• Edema or tenderness extending beyond the cutaneous erythema
• Crepitus/gas in subcutaneous tissue
• Rapid progression despite antimicrobial therapy
• Bullae (containing thick pink or purple fluid) or cutaneous necrosis
• Loss of sensation of affected area

Last reviewed January 2023

• Clinical assessment including surgical exploration
  • Intraoperative tissue specimens should be sent for microbiologic culture to guide antimicrobial therapy.
• 2 sets of blood cultures
• X-ray and CT may show gas in tissue, but DO NOT delay treatment for imaging and normal imaging does not rule out the diagnosis of a necrotizing infection.

Last reviewed January 2023

• Contact and droplet precautions for 24 hours from initiation of appropriate antimicrobial therapy
• Surgical emergency: requires URGENT prompt surgical consultation
• Report to Public Health as soon as invasive group A streptococcus infection is suspected.

Last reviewed January 2023

• Piperacillin-tazobactam 3.375 g IV q6h
• Add clindamycin 900 mg IV q8h if concern of Type II infection
• Add Vancomycin If MRSA risk factors such as:
  • Injection drug use, recurrent abscesses, known MRSA colonization, previous MRSA infection

Last reviewed January 2023

• History of true IgE-mediated penicillin allergy (e.g., anaphylaxis):
  • Meropenem 500 mg IV q6h
  • Add clindamycin 900 mg IV q8h if concern of Type II infection

Last reviewed January 2023

• Immunoglobulin (IVIG) can reduce circulating toxins and may reduce mortality in patients with group A streptococcus necrotizing fasciitis with associated shock.
• Review tetanus immunization status
• Clindamycin is used to suppress toxin production
  • Verify that isolated pathogen is sensitive

Last reviewed January 2023

• Tailor antimicrobial therapy to culture and sensitivity results
  • Can discontinue clindamycin if Type I polymicrobial infection
• Recommended therapies:
  • Group A streptococcus (Streptococcus pyogenes) 
    • Penicillin G 4 million units IV q4h and clindamycin 900 mg IV q8h 
    • Consider adding IVIG if in shock (see PPO for dosing)   
  • Clostridium spp.
    • Penicillin G 4 million units IV q4h plus clindamycin 900 mg IV q8h

Last reviewed January 2023

• Continue antimicrobial therapy until no further debridement is necessary, patient is clinically improved and afebrile for 48-72 hours, unless there is a concomitant infectious syndrome, such as osteomyelitis or septic arthritis requiring a longer treatment course.
• Clindamycin
  • Continue until hemodynamically and clinically stable after initial debridement.
  • If concomitant toxic shock syndrome, continue clindamycin 5-7 days if clindamycin susceptible.

Last reviewed January 2023

1. Alberta Health Services (2021). Necrotizing fasciitis/myositis in Adults – Culture proven in Bugs & Drugs [Mobile app]. Retrieved January 11, 2021 from http://bugsanddrugs.ca/

2. Stevens DL, Bisno AL, Chambers HF et al. Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America. Clin Infect Dis. 2014;59(2):147-59.

3. Stevens DL, Bryant AE. Necrotizing soft-tissue infections. N Engl J Med 377(23):2253–2265, 2017.

Last reviewed January 2023

• Staphylococcus aureus
  • MRSA: If previous MRSA infection or colonization
• Streptococci, Enterococci, Gram-negative bacilli, and anaerobes are less common

Last reviewed January 2021

• New or worsening back pain, often severe, with
  • Elevated inflammatory markers
  • Fever (only ~50%)
  • Current or recent bloodstream infection/infective endocarditis
• Fever with new neurological symptoms

Last reviewed January 2021

• Delay empiric antibiotics until microbiologic diagnosis unless
  • Septic or neurologic compromise (perform a thorough neurological history and physical exam)
  • Concomitant presence of S. aureus bloodstream infection within the preceding 3 months and compatible spine MRI changes preclude the need for a disc space aspiration, as the etiology can be assumed to be S. aureus.
• MRI is preferred imaging to exclude the presence of discitis, osteomyelitis, and/or epidural abscess
  • Early destructive changes can be missed with CT, which is not sensitive for epidural abscess
• 2 sets of blood cultures: positive in ~50% of cases
• Biopsy/aspirate via interventional radiology or by surgical intervention

Last reviewed January 2021

• Assess for extension of infection (e.g. psoas abscess, epidural abscess, empyema)
• Assess for other sites of metastatic infection (e.g. endocarditis, septic joint, hardware infection)
• Regularly assess condition since neurological status can change quickly, urgent neurosurgery consultation if neurological symptoms or signs are present
• The presence of an epidural abscess requires consultation with Neurosurgery and close monitoring of neurological status
• Infectious Diseases should be consulted

Last reviewed January 2021

• Cefazolin 2g IV q8h (may require renal dose adjustment) is the empiric drug of choice
• Target antibiotics based on culture results

Last reviewed January 2021

Usually 6 weeks of intravenous therapy and then reassessment

Last reviewed January 2021

1. Berbari EF, Kanj SS, Kowalski TJ, et al. 2015 Infectious Diseases Society of America (IDSA) Clinical Practice Guidelines for the Diagnosis and Treatment of Native Vertebral Osteomyelitis in Adults. Clin Infect Dis. 2015;61(6):e26-e46.

2. Park KH, Cho OH, Lee JH, et al. Optimal Duration of Antibiotic Therapy in Patients With Hematogenous Vertebral Osteomyelitis at Low Risk and High Risk of Recurrence. Clin Infect Dis. 2016;62(10):1262-1269.

3. An HS, Seldomridge JA. Spinal infections: diagnostic tests and imaging studies. Clin Orthop Relat Res. 2006 Mar;444:27-33.

Last reviewed January 2021