What antibiotic (ATB) is recommended for a patient without diabetes who has a wound in the leg?

Antibiotic Selection for Non-Diabetic Leg Wound Infections

For a non-diabetic patient with a leg wound, first-line antibiotic therapy should be a beta-lactam antibiotic such as cephalexin (500 mg four times daily) or flucloxacillin (1 g four times daily) for 7-10 days. These antibiotics provide appropriate coverage against the most common pathogens in uncomplicated wound infections, primarily Staphylococcus aureus and streptococci 1.

Antibiotic Selection Algorithm

1. Assess infection severity:

   • Mild infection: Limited to superficial skin with minimal surrounding erythema (<2 cm)
   • Moderate infection: More extensive with erythema >2 cm, possible lymphangitis, mild systemic symptoms
   • Severe infection: Systemic signs (fever >38°C, tachycardia), extensive erythema, deep tissue involvement

2. Select antibiotic based on severity:

   Mild Infection

   • First-line: Cephalexin 500 mg four times daily OR flucloxacillin 1 g four times daily
   • Beta-lactam allergy: Clindamycin 300-450 mg three times daily OR trimethoprim-sulfamethoxazole 160/800 mg twice daily

   Moderate Infection

   • First-line: Same as mild infection but consider broader coverage if risk factors present
   • If recent antibiotic exposure: Add coverage for gram-negative organisms (amoxicillin-clavulanate 875/125 mg twice daily)

   Severe Infection

   • Inpatient treatment: IV antibiotics (e.g., ampicillin-sulbactam, cefazolin, or piperacillin-tazobactam)
   • Consider MRSA coverage: Add vancomycin if risk factors present

Risk Factors Requiring Broader Coverage

• Recent hospitalization
• Previous antibiotic therapy within past month
• Known colonization with resistant organisms
• Immunocompromised status
• Presence of foreign body in wound
• Chronic wound with prior treatment failure

Duration of Therapy

• Mild infections: 7-10 days
• Moderate infections: 10-14 days
• Severe infections: 14-21 days 1

Wound Management Principles

1. Obtain cultures before starting antibiotics when possible, especially for moderate to severe infections

   • Deep tissue cultures preferred over swabs 1

2. Perform appropriate wound care:

   • Sharp debridement of necrotic tissue
   • Wound cleansing with saline or water
   • Appropriate dressing selection based on wound characteristics
   • Consider offloading pressure from affected area 1

3. Monitor response to therapy:

   • Improvement in local signs (decreased erythema, swelling, pain)
   • Resolution of systemic symptoms if present
   • Consider changing antibiotics if no improvement after 48-72 hours

Special Considerations

• MRSA coverage should be added if patient has prior history of MRSA, high local prevalence, or severe infection 2, 1
• Pseudomonas coverage is rarely needed in community-acquired infections unless specific risk factors exist 1
• Topical antimicrobial therapy may be considered for very superficial infections but is generally insufficient for true cellulitis 2

Common Pitfalls to Avoid

1. Treating uninfected wounds with antibiotics - antibiotics do not promote healing in uninfected wounds and contribute to antibiotic resistance 1

2. Using inadequate dosing - ensure proper dosing and frequency to maintain therapeutic levels

3. Continuing ineffective antibiotics - reassess after 48-72 hours and adjust therapy if no improvement 1

4. Excessive duration of therapy - prolonged courses increase risk of adverse effects and resistance without additional benefit

5. Relying on swab cultures - these often reflect surface colonization rather than true pathogens 1

Remember that while antibiotic therapy is necessary for infected wounds, it is often insufficient without appropriate wound care including debridement, cleansing, and proper dressing selection 2.