Antibiotic Therapy for Bacterial Infections

Animal Bites and Infections

• Approximately 2 to 5 million animal bites occur annually, accounting for 1% of emergency department visits and 10,000 inpatient admissions annually.
• Dog bites account for 90% of animal bites, while cat bites account for 10%.
• In children, dog bites often involve the head and neck, while in adolescents and adults, they usually involve the extremities.
• Cat bites typically occur on the extremities and tend to penetrate deeply, resulting in a higher risk of deep infection.

Pasteurella Multocida Infections

• Characterized by rapid development of an intense inflammatory response within 24 hours of the initial injury.
• Symptoms include pain, swelling, purulent drainage, lymphangitis, and regional lymphadenopathy.
• Definitive therapy: Penicillin G, Amoxicillin-clavulanate, Cefuroxime, or Ciprofloxacin.

Capnocytophaga Infections

• Definitive therapy: Piperacillin-tazobactam or Imipenem.

Cat-Scratch Disease

• Definitive therapy for lymphadenitis: Azithromycin (500 mg PO on day 1, followed by 250 mg PO for four days).
• Definitive therapy for more serious infections: Rifampin (300 mg PO/IV twice daily) plus azithromycin (500 mg PO/IV on day 1, followed by 250 mg PO/IV daily), both administered for 10 to 14 days.

Tetanus Prophylaxis

• Wound management and tetanus prophylaxis are necessary for all wounds.
• Tetanus toxoid-containing vaccine is recommended for all wounds, with additional Human Tetanus Immune Globulin (HTIG) for certain wounds.

Rabies Prophylaxis

• Rabies prophylaxis is necessary for all animal bites.

Management of Animal Bites

• Antibiotic prophylaxis is indicated for:
  • Lacerations undergoing primary closure and wounds requiring surgical repair.
  • Wounds on the hand(s), face, or genital area.
  • Wounds in close proximity to a bone or joint.
  • Wounds in areas of underlying venous and/or lymphatic compromise.
  • Wounds in immunocompromised hosts (including diabetes).
  • Deep puncture wounds or laceration (especially due to cat bites).
  • Wounds with associated crush injury.
• Preferred antibiotic prophylaxis: Amoxicillin-clavulanate 875/125 mg twice daily or alternative agents.
• Duration of prophylactic oral antibiotics is three to five days with close follow-up.

Surgical Consultation

• Indicated for:
  • Complex facial lacerations.
  • Deep wounds that penetrate bone, tendons, joints, or other major structures.
  • Wounds associated with neurovascular compromise.
  • Infections involving the hands or face.
  • Infections associated with neurovascular compromise.
  • Presence of crepitus.
  • Persistent signs and symptoms of infection despite appropriate antibiotic therapy.
  • Debridement.