A 2-year-old patient in my practice with acute otitis media that has progressed to mastoiditis with a high fever returns with positive culture results for Fusobacterium What should I do next?Fusobacterium is a genus of anaerobic bacteria. Although Fusobacterium infections are rare, they can become severe if not treated promptly. Appropriate treatment is combination antibiotic therapy consisting of a β-lactam (penicillin, cephalosporin) and an anaerobic antimicrobial agent (metronidazole, clindamycin). At times surgical involvement is required for mastoiditis such as drainage of abscesses or insertion of a ventilation tube. Delayed treatment of an infection caused by Fusobacterium can lead to serious complications, including Lemierre syndrome. Children should be seen in a hospital for close monitoring.