What is the risk of infection 12 hours after being bitten and scratched by a cat?

Risk of Infection from Cat Bites and Scratches

Cat bites and scratches have a high risk of infection, with approximately 50% of cat bites becoming infected if not properly treated within 12 hours of injury. 1 Immediate wound care and possibly antibiotics are necessary to prevent serious complications.

Immediate Wound Care (Critical First Step)

• Thoroughly wash and flush all bite wounds and scratches immediately for about 15 minutes with soap and water 2
• Apply an iodine-containing or similarly virucidal topical preparation to the wound where available 2
• Deep irrigation and removal of necrotic tissue is crucial in preventing cat-related infections 3

Infection Risk Factors

Cat bites and scratches pose significant infection risks because:

• Cat bites create puncture wounds that can inoculate bacteria deep into tissues
• Cat mouths harbor multiple pathogens:
  • Pasteurella species are isolated from 75% of cat bite wounds 1
  • Staphylococci and streptococci are found in approximately 40% of cat bites 1
  • Anaerobic bacteria are present in 65% of cat bites 1
  • Bartonella henselae, which causes cat scratch disease, may be transmitted 4

Antibiotic Recommendations

Given that it has been 12 hours since your injuries, antibiotic treatment is strongly recommended:

• First-line treatment: Amoxicillin-clavulanate (oral therapy) 1
• Alternative options for those with penicillin allergies:
  • Doxycycline plus metronidazole
  • Fluoroquinolones (ciprofloxacin, levofloxacin) plus metronidazole 1

Avoid using first-generation cephalosporins, penicillinase-resistant penicillins, macrolides, or clindamycin alone as they have poor activity against Pasteurella multocida 1

When to Seek Medical Care

With multiple bites and scratches that occurred 12 hours ago, you should:

1. Seek medical care immediately
2. The wounds may already be showing early signs of infection
3. Healthcare providers can properly clean the wounds and prescribe appropriate antibiotics

Potential Complications to Watch For

Without proper treatment, potential complications include:

• Local infection with cellulitis
• Abscess formation (occurs in 19% of cat bites) 1
• Septic arthritis if near joints
• Osteomyelitis if near bones
• Tendonitis
• Rarely, bacteremia 1
• Cat scratch disease (regional lymphadenopathy, fever) 4, 5

Additional Considerations

• Rabies risk assessment: The biting cat should be observed for 10 days if possible 1
• Tetanus prophylaxis: Should be administered as indicated based on vaccination status 2
• Hand wounds are often more serious than wounds to fleshy parts of the body 1

Remember that pain disproportionate to the severity of injury but located near a bone or joint should suggest periosteal penetration, which requires more aggressive treatment 1.