Diabetic Foot Infections

Question 1

How are diabetic foot infections defined?

Answer 1

Any type of skin, soft tissue, or bone infection below the ankle in patients with diabetes

Question 2

What infections are included in diabetic foot infections? (8)

Answer 2

1. Cellulitis
2. Paronychia (nail inflammation)
3. Abscesses
4. Myositis
5. Tendonitis
6. Necrotising fasciitis
7. Osteomyelitis
8. Septic arthritis

Question 3

What is the immediate management of diabetic foot infections?

Answer 3

Refer immediately to acute services

Abx should be started ASAP if diabetic foot infection is suspected; samples should e taken before, or as close as possible to, the start of abx treatment

Question 4

What are the signs of limb-threatening and life-threatening diabetic foot infections? (4)

Answer 4

1. Ulceration with fever
2. Any signs of sepsis
3. Ulceration with limb ischemia
4. Gangrene

Question 5

What factors should be taken into account when choosing antibacterial therapy for management of diabetic foot infections? (4)

Answer 5

1. Clinical assessment
2. Infection severity
3. Suspected micro-organism
4. Microbiological results when available

**review the need for continued or adjusted antibacterials regularly

Question 6

What organisms are most commonly implicated in diabetic foot infections? (7)

Answer 6

Gram (+): Staph aureus, Enterococc
Gram (-): Pseudomonas, E.coli, Klebsiella, Proteus
Anaerobes

• often multi-drug resistant due to formation of biofilms that allow bacterial communities to survive and evade abx
  https: //www.ncbi.nlm.nih.gov/pmc/articles/PMC4592943/

Question 7

What is the treatment of choice for mild diabetic foot infections?

Answer 7

FIRST LINE:
- oral flucloxacillin (targets staph, the most common organism)

SECOND LINE:
- clarithromycin, doxycycline, or erythromycin (in pregnancy) IF penicillin allergy or flucloxacillin unsuitable

Question 8

What is the treatment of choice in moderate to severe diabetic foot infection?

Answer 8

FIRST LINE:

• oral or IV flucloxacillin with or without IV gentamicin and/or metronidazole
• oral or IV co-amoxiclav with or without IV gentamicin
• IV ceftriaxone with metronidazole

SECOND LINE: (if penicillin allergy)
- co-trimoxazole with or without IV gentamicin and/or metronidazole

*add additional coverage if Pseudomonas or MRSA suspected or confirmed

Question 9

When is oral abx administration preferred to IV in the treatment of diabetic foot ulcers?

Answer 9

Oral abx are preferred for for MILD or PROLONGED treatment (eg. 7 days to 6 weeks for osteomyelitis)

VS

Intravenous abx are preferred for severe infection (given for at least 48 hours)

Question 10

What abx should be added to drug regimen if Pseudomonas is suspected or confirmed? (2 options)

Answer 10

• IV piperacillin with tazobactam OR

- clindamycin with ciprofloxacin and/or IV gentamicin

Question 11

What abx should be added to the treatment regimen if MRSA is confirmed or suspected? (3 options)

Answer 11

• IV vancomycin OR
• IV tecoplanin OR
• linezolid (specialist use only if vancomycin or teicoplanin cannot be used)

Question 12

What is the dosage of flucloxacillin for mild diabetic foot infection?

Answer 12

0.5-1 g PO, 4 times a day for 7 days, then review

Question 13

What is the dosage of flucloxacillin for moderate-severe diabetic foot infection?

Answer 13

By mouth:
- 1 g 4 times a day

By slow IV injection or by IV infusion:
- 1-2 g every 6 hours

Question 14

What is the main risk that should be taken into consideration when thinking about drug interactions with flucloxacillin?

Answer 14

Potential for interactions with other hepatotoxic drugs leading to liver injury eg. alcohol, statins, carbamazepine, INH, -anoles, paracetamol, etc.

Question 15

What organism should be suspected if blue-green pigment is visualized at the site of an ulcer?

Answer 15

Pseudomonas