From the Guidelines
The most common infection from a cat bite is caused by Pasteurella multocida, a bacterium that naturally resides in the mouths of cats. When a cat bite punctures the skin, this organism can be introduced deep into tissues, causing an infection that typically develops rapidly, often within 24-48 hours 1. Signs of infection include redness, swelling, increasing pain, and possibly pus drainage at the bite site.
Key Points to Consider
- Treatment usually involves antibiotics such as amoxicillin-clavulanate (Augmentin) at a typical dose of 875/125 mg twice daily for adults for 5-7 days, as recommended by the Infectious Diseases Society of America 1.
- For those with penicillin allergies, alternatives include doxycycline, trimethoprim-sulfamethoxazole, or fluoroquinolones, with considerations for their effectiveness against specific bacteria and potential resistance patterns 1.
- It's crucial to clean any cat bite thoroughly with soap and water immediately and seek medical attention promptly, as these infections can progress quickly due to the deep puncture wounds created by cats' sharp teeth, which can introduce bacteria into difficult-to-clean spaces.
- People with compromised immune systems, diabetes, or bites on the hands, joints, or face should be especially vigilant about seeking immediate care, given the higher risk of severe infection and complications in these populations.
Important Considerations for Management
- The choice of antibiotic should be guided by the severity of the infection, the presence of any underlying health conditions, and the potential for antibiotic resistance, as outlined in the practice guidelines for the diagnosis and management of skin and soft tissue infections 1.
- Regular follow-up with a healthcare provider is essential to monitor the infection's response to treatment and adjust the treatment plan as necessary.
From the Research
Infection by Cat Bite
- The most common infection caused by a cat bite is Pasteurella multocida, a gram-negative bacterium that is commonly found in the oral cavity of cats 2, 3, 4.
- According to a study published in the Journal of Zoonoses and Public Health, approximately 20-80% of all cat bites will become infected with Pasteurella multocida, compared to only 3-18% of dog bite wounds 2.
- Another study published in Pediatrics in Review found that cat bites have a twofold higher risk of infection than dog bites, with Pasteurella multocida being the most frequent and important pathogen 3.
Characteristics of Pasteurella multocida Infection
- Pasteurella multocida is a zoonotic infectious organism that can cause a range of diseases in humans, including septic shock, bacteremia, and localized infections 4, 5.
- A study published in the Journal of Medicine found that patients with Pasteurella multocida infections who did not have an animal bite were more frequently bacteremic and required hospitalization and intensive care unit (ICU) management more often than those with an animal bite 5.
- The same study found that Pasteurella multocida infections not associated with an animal bite were often associated with severe comorbidities, immune-incompetent states, and substantial mortality 5.
Antibiotic Susceptibility
- Pasteurella multocida is generally susceptible to most antibiotics, including penicillin, amoxicillin-clavulanate, cefazolin, and azithromycin 2, 6.
- However, resistance to certain antibiotics, such as sulphonamides, tetracyclines, and aminoglycosides, has been reported, and the use of these antibiotics is not recommended for the treatment of Pasteurella multocida infections 6.