We describe a 62-year-old woman with a 1-month-old unhealed cat bite wound caused by Mycobacterium chelonae presenting with persistent infection despite treatment with cefazolin and amoxicillin. This is the first reported case of M. chelonae infection caused by a cat bite. Cat bites are affected by the cat's food microbiome, so clinicians should consider the cat's diet if wounds are not responding as expected to first-line therapy.