The rate of infection following cat bites appears to be greater than that from dog bites. To study the clinical picture, complications and microbiology (in humans and cats), this prospective study was performed.

A prospective study with patients with clinical symptoms of infection due to cat bites from three emergency wards during two years in Stockholm, Sweden. Aerobic and anaerobic cultures from the wounds were performed as well as cultures from the biting cat's mouth. Clinical data and complications were registered.

Seventy-nine episodes in 78 patients with infective cat bites were included. Pasteurella multocida was isolated in 70% of the patients; in addition anaerobic pathogens were isolated in 16% concurrently with P. multocida, while Staphylococcus aureus was isolated in only two patients. Pasteurella spp. was also isolated from 80% of the pharynx of the biting cats. The dominating symptoms of infection were erythema, pain and oedema, often emerging as early as 3h after the bite. Complications such as tendosynovitis, arthritis, abscesses and septicaemia occurred in 18% of the patients. No patient died due to the infection. The majority of the patients received penicillin or amoxicillin as antibiotic treatment.

P. multocida was the dominating pathogen among patients with infected cat bites and antibiotic treatment should cover P. multocida.