A 70-year-old male with a history of prostate cancer presented with a chronic, nonhealing perineal wound and recurrent abscesses following prostatectomy. Initial cultures were negative for aerobic and fungal growth, but tissue biopsy revealed acid-fast bacilli. Further anaerobic culture and 16S rRNA gene sequencing identified the causative agent as *Mycobacterium goodii*. This unusual presentation of a rapidly growing mycobacterium, typically associated with skin and soft tissue infections, highlights diagnostic challenges. The patient underwent surgical debridement and received targeted antibiotic therapy, leading to clinical improvement.
Key note: *Mycobacterium goodii* can cause chronic, nonhealing wounds, and its anaerobic nature combined with acid-fast staining can complicate diagnosis.