Abstract
BACKGROUND: Capnocytophaga canimorsus is a commensal bacterium found in the normal oral microbiota of dogs and cats. It can cause severe systemic infections, such as bacteremia and meningitis, in both immunocompromised and immunocompetent humans. CASE SUMMARY: We present a case of C. canimorsus bacteremia and meningitis with fever, headache, and altered mental status, which posed diagnostic challenges due to the administration of antimicrobials prior to specimen collection. CONCLUSION: This case highlights the value of molecular methods in diagnosing severe infections caused by fastidious bacteria and in cases of antibiotic use before culture.