Diabetic Foot Infections – Grades and Treatments

IDSA Diabetic Foot Guidelines

Here is the IDSA/IWGDAF grading with some sample treatment. More specific treatment recommendations can be found in IDSA 2023 recommendations below. It is no longer recommended to add anaerobic therapy unless patient has ischaemic limb/necrosis/gas forming features. Patient specific factors should drive empiric choices.

Grade	Infection Severity	Clinical Manifestations	Treatment Location
1	Uninfected	Wound without purulence or inflammation	Outpatient
2	Mild	Infected: At least two of these items are present: -Local swelling or induration -Erythema >0.5 but <2 cmb around the wound -Local tenderness or pain -Local increased warmth -Purulent discharge *And, no other cause of an inflammatory response of the skin (e.g., trauma, gout, acute charcot neuro-arthropathy, fracture, thrombosis, or venous stasis)	Mostly Outpatient—Oral
3	Moderate	Infection with no systemic manifestations and involving: -Erythema extending ≥2 cmb from the wound margin, and/or -Tissue deeper than skin and subcutaneous tissues (e.g., tendon, muscle, joint, and bone)	Hospital—IV or PO
4	Severe	Any foot infection with associated systemic manifestations (of the systemic inflammatory response syndrome [SIRS]), as manifested by ≥2 of the following: -Temperature, > 38°C or <36°C Heart rate, > 90 beats/min -Respiratory rate, > 20 breaths/min, or PaCO2 < 4.3 kPa (32 mmHg) -White blood cell count >12,000/mm3 , or < 4G/L, or 10% immature (band) forms	Hospital, possibly ICU—IV
For infection involving bone (osteomyelitis), grade 3(O) or 4(0) if 2 or more SIRS criteria

**New IDSA Guidelines 2023**

Infection severity	Additional factors	Usual pathogen(s)	Potential empirical regimens
Mild	No complicating features	GPC	Semisynthetic penicillinase-resistant penicillin (cloxacillin) or 1st generation cephalosporin (cephalexin)
	ß-lactam allergy or intolerance	GPC	Clindamycin, Fluoroquinolone (levo/moxifloxacin), trimethoprim-sulfamethoxazole or doxycycline
	Recent antibiotic exposure	GPC + GNR	ß-lactam- ß lactamase inhibitor (amoxicillin /clavulanate, ampicillin/sulbactam), Fluoroquinolone (levo/moxi-floxacin) or Trimethoprim-sulfamethoxazole
	High risk for MRSA	MRSA	Linezolid, Ttrimethoprim-sulfamethoxazole, Clindamycin, Doxycycline, or Fluoroquinolone (levofloxacin, moxifloxacin)
Moderate or severe	No complicating features	GPC ± GNR	ß-lactam- ß lactamase inhibitor1 (amoxicillin /clavulanate, ampicillin/sulbactam), or 2nd , 3rd generation cephalosporins (cefuroxime, cefotaxime, ceftriaxone)
	Recent antibiotics	GPC ± GNR	ß-lactam- ß lactamase inhibitor2 (ticarcillin /clavulanate, piperacillin/tazobactam), 2nd , 3rd generation cephalosporins (cefuroxime, cefotaxime, ceftriaxone), or group 1 carbapenem (ertapenem) (depends on prior therapy; seek advice)
	Macerated ulcer or warm climate	GNR, including Pseudomonas sp.	ß-lactam- ß lactamase inhibitor2 (ticarcillin /clavulanate, piperacillin/tazobactam), semisynthetic penicillinase-resistant penicillin (cloxacillin) + ceftazidime or ciprofloxacin, or group 2 carbapenem (meropenem)
	Ischaemic limb/necrosis/gas forming	GPC ± GNR ± strict Anaerobes	ß-lactam- ß lactamase inhibitor1 (amoxicillin /clavulanate, ampicillin/sulbactam) or ß-lactam- ß lactamase inhibitor2 (ticarcillin /clavulanate, piperacillin/tazobactam), Group 1 (ertapenem) or 2 (meropenem) carbapenem, 2nd (cefuroxime) /3rd (cefotaxime, ceftriaxone) generation cephalosporin + clindamycin or metronidazole
	MRSA risk factors	MRSA	Consider adding, or substituting with glycopeptides (vancomycin, teicoplanin), Linezolid; daptomycin, trimethoprim-sulfamethoxazole, or doxycycline
	Risk factors for resistant GNR	ESBL	Carbapenem (meropenem), fluoroquinolone (ciprofloxacin), aminoglycoside (amikacin), colistin
Abbreviations: GNR, gram-negative rod; GPC, gram-positive cocci (staphylococci and streptococci); MRSA, methicillin-resistant Staphylococcus aureus ; ESBL: extended-spectrum ß-lactamase

Duration of therapy should be individualized.

• For those treated in outpatient settings with oral antibiotics, duration of treatment is usually 7-14 days.
• Treat for 2-4 weeks for moderate to severe infections.  Consider continuing treatment for up to 3–4 weeks if the infection is improving but is extensive and is resolving slower than expected.
• After amputation or resection, continue 2-5 days.
• After bone or joint debridement, 1-2 weeks (as few as 10 days following surgical debridement).
• Consider a duration of up to 3 weeks of antibiotic therapy after minor amputation for diabetes-related osteomyelitis of the foot and positive bone margin culture
• Treat for 6 weeks for diabetes-related foot osteomyelitis without bone resection or amputation

You can change to PO therapy when appropriate after initial IV doses.

Factors that should lead to considering hospitalisation:

• Severe infection (see findings suggesting a more serious diabetes-related foot infection above)
• Metabolic or haemodynamic instability
• Intravenous therapy needed (and not available/appropriate as an outpatient)
• Diagnostic tests needed that are not available as an outpatient
• Severe foot ischaemia is present
• Surgical procedures (more than minor) required
• Failure of outpatient management
• Need for more complex dressing changes than patient/caregivers can provide
• Need for careful, continuous observation

Osteomyelitis:

Signs and symptoms – fever, chills, localized pain, tenderness, swelling

Treatment:

• Peds: cefazolin, nafcillin, oxacillin, clindamycin (MRSA resistance >10), vancomycin (if MRSA and clindamycin resistance >10)
• Adults: nafcillin, oxacillin, cefazolin, ceftriaxone, clindamycin, vancomycin
• Treat 4-6 weeks.
• Add rifampin for prosthetic joints.