New insights in diabetic foot infection

Table 1 International consensus on the diabetic foot classification of foot wound infections (adapted from reference [17])

Grade 1	No symptoms, no signs of infection
Grade 2	Lesion only involving the skin (no subcutaneous tissue lesion or systemic disorders) with at least two of the following signs:
	Local warmth
	Erythema > 0.5 cm - 2 cm around the ulcer
	Local tenderness or pain
	Local swelling or induration
	Purulent discharge (thick, opaque to white or sanguineous secretion)
	Other causes of inflammation of the skin must be eliminated (for example: trauma, gout, acute Charcot foot, fracture, thrombosis, venous stasis)
Grade 3	Erythema > 2 cm and one of the findings described above
	or
	Infection involving structures beneath the skin and subcutaneous tissue, such as deep abscess, lymphangitis, osteomyelitis, septic arthritis or fasciitis
	There must not be any systemic inflammatory response (see Grade 4)
Grade 4	Regardless of the local infection, in the presence of systemic signs corresponding to at least two of the following characteristics:
	Temperature > 39°C or < 36°C
	Pulse > 90 bpm
	Respiratory rate > 20/min
	PaCO2 < 32 mmHg
	Leukocytes > 12 000 or < 4 000/mm3
	10% of immature leukocytes

Table 2 Factors to be considered for antibiotic prescription in diabetic foot infection (adapted from reference [17])

Criteria	Comments
Severity of infection	Broad-spectrum therapy via parenteral route for severe infection
Renal dysfunction	Avoid nephrotoxic agents (aminoglycosides, glycopeptides)
Hepatic dysfunction	Avoid hepatotoxic agents (macrolides, amoxicillin/clavulanate)
Ischemic limb	Use relatively high doses of oral antibiotics or prefer IV route to achieve adequate antibiotic level at the site of infection if revascularization procedure is unfeasible
	Consider anti-anaerobic bacteria when there is ischaemia or extensive devitalized tissue
Impaired gastrointestinal function (gastroparesis)	Prefer parenteral route
Local antibiotic resistance patterns	Cover MRSA if indicated
Drug allergies	Review patient's medical history carefully
History of recent antibiotic treatment	May need an extended coverage against gram-negative bacilli and Enterococcus
Chronicity of the wound	Give preference to broad-spectrum therapy initially
Poor therapeutic compliance	Consider IV route and/or hospitalization

MRSA: methicillin-resistant Staphylococcus aureus.