Diabetic Foot Infection

Antimicrobial prescribing: NHS Lothian
NHS Lothian

Patients should be managed by a multidisciplinary diabetic foot care team.

Seek specialist advice from diabetic foot clinic at RIE (Dr Matthew Young) or SJH (Dr Karen Adamson)

Assessment

Use the answers to the following 4 questions to decide on the antibiotic choices in the guidance below.

  1. Has the patient been identified as a carrier of MRSA or had an infection caused by MRSA? If so use the recommendations for MRSA. Check that the MRSA isolates are sensitive to the suggested antibiotics. 
  2. Has the patient received antibiotics in the last month? If "Yes", then use the non-antibiotic naive recommendations.
  3. Does the patient have a penicillin allergy label? If so review the nature of the allergy here. If the label of allergy is felt to be accurate then follow the recommendation for penicillin allergy.
  4. Use the table below to decide on the severity of infection.
Mild

Absence of systemic inflammatory response syndrome AND:

  • Local swelling or induration OR
  • Erythema >0.5cm but < 2 cm around the ulcer OR
  • Local tenderness or pain OR
  • Local increased warmth OR
  • Purulent discharge 
Moderate

Absence of systemic inflammatory response syndrome AND:

  • Erythema >2cm from wound margin OR
  • Infection of tissue deeper than skin/subcutaneous tissue (i.e. tendon, muscle, joint, bone)
Severe

Any foot infection associated with presence of systemic inflammatory response syndrome, defined as ≥ 2 of:

  • Temperature >38C or <36C
  • Heart rate >90 beats/min
  • Respiratory rate >20 breaths/min
  • White blood cell count >12 x109/L or <4 x109/L

If previous organisms related to the current infection that are resistant to the antibiotics recommended contact microbiology.

Required investigations

  • Blood cultures (10mls per bottle) for severe infection, before starting IV antibiotics
  • X-rays (check for osteomyelitis; if severe infection or patient not improving)
  • Consider bone biopsy prior to antibiotics if osteomyelitis is identified.
  • Consider assessing arterial supply and need for debridement.

Mild infection

Recommended duration: 7 days (Total duration = IV + oral)

Antibiotic naive

 Flucloxacillin 1g every 6 hours orally

Non-antibiotic naive OR

 

Penicillin allergy OR Previous MRSA (check sensitivities) 

Doxycycline 100mg every 12 hours orally

OR

Co-trimoxazole 960mg every 12 hours orally

 

 

Moderate infection

Recommended duration: 7 days 

(Total duration = IV + oral) Antibiotic naive

Flucloxacillin 1g every 6 hours orally or 2g every 6 hours IV (if deep tissue infection)

AND

Metronidazole 400mg every 8 hours orally

Non-antibiotic naive OR

Penicillin allergy OR previous MRSA (check sensitivities)

 

Oral therapy

Co-trimoxazole 960mg every 12 hours orally

AND

Metronidazole 400mg every 8 hours orally

IV therapy:

Vancomycin IV (use NHS Lothian Calculator located AMT intranet page) choose trough 15-20mg/L

AND

Metronidazole 400mg every 8 hours orally (500mg every 8 hours IV if oral route unavailable)

 

Severe infection

Recommended duration: 7 days minimum (Total duration = IV + oral) 

  • Discuss all severe cases with microbiology and the diabetic foot team. 
  • Patients may need prolonged courses of antibiotics (particularly if there is osteomyelitis)
Antibiotic naive

Flucloxacillin 2g every 6 hours IV

AND

Gentamicin IV (use NHS Lothian Calculator located AMT intranet page)

AND

Metronidazole 400mg every 8 hours orally (500mg every 8 hours IV if oral route unavailable)

Non-antibiotic naive OR

Penicillin allergy OR previous MRSA

 

Vancomycin IV (use NHS Lothian Calculator located AMT intranet page) choose trough 15-20mg/L

AND

Gentamicin IV (use NHS Lothian Calculator located AMT intranet page)

AND

Metronidazole 400mg every 8 hours orally (500mg every 8 hours IV if oral route unavailable)

Therapy if Pseudomonas aeruginosa suspected/confirmed

Antibiotic recommendation

Piperacillin-tazobactam 4.5g every 6 hours IV

Previous MRSA

Vancomycin IV (use NHS Lothian Calculator located AMT intranet page); trough 15-20

AND

Piperacillin-tazobactam 4.5g every 6 hours IV

Penicillin allergy

Vancomycin IV (use NHS Lothian Calculator located AMT intranet page); trough 15-20

AND

Gentamicin IV (use NHS Lothian Calculator located AMT intranet page)

AND

Metronidazole 400mg every 8 hours orally (500mg every 8 hours IV if oral route unavailable)

 

 

 

Presence of Osteomyelitis

Consider bone biopsy prior to antibiotics if osteomyelitis is identified

Discuss with specialist teams (e.g. diabetic foot service, microbiology)

Durations below may be recommended (Total duration = IV + oral):

Infected bone fully resected: short duration (2-5 days)

Bone margin remains culture positive after resection: 3 weeks

No surgery/dead bone remains in situ: 6 weeks

IV to oral switch

Discuss oral switch options with an infection specialist. Checklist - before you phone microbiology.

Notes

Likely organism: often polymicrobial and/or Staphylococcus aureus often isolated