Cat Bite-Associated Infections of the Upper Extremity Requiring Surgical Treatment: A Report of Two Cases Involving Pasteurella multocida and Capnocytophaga felis

Although cat bite-associated infections of the upper extremity are common, their impact might be underestimated due to the mild initial clinical findings. However, such infections could progress to deep musculoskeletal involvement and require surgical intervention. Herein, we report two cases of cat bite-associated infections of the upper extremities that required surgical treatment. The first case involved a rapidly progressing forearm infection caused by Pasteurella multocida that was successfully managed with surgical debridement and appropriate antimicrobial therapy. In contrast, the second case comprised an indolent clinical course with osteomyelitis of the first metacarpal bone and minimal inflammatory findings. Conventional cultures failed to identify the causative organism, and genetic testing was required to detect Capnocytophaga felis. The patient was successfully treated with surgical debridement and prolonged antimicrobial therapy, with no sign of recurrence. To the best of our knowledge, this is the first report of osteomyelitis caused by this organism. These contrasting clinical courses underscore the diversity of the feline oral microbiota and the causative pathogen-dependent disease presentation variability. When clinical improvement is not achieved with initial medical management, timely surgical intervention is essential. Furthermore, when the causative pathogen cannot be identified using conventional culture methods, genetic testing should be considered to ensure accurate diagnosis and appropriate treatment.