A 54-year-old immunocompetent male presented with a 1.5-year history of a non-healing, painful, ulcerative lesion on his left forearm, initially misdiagnosed as a spider bite. Despite multiple biopsies, no definitive diagnosis was made. The lesion progressed, leading to extensive tissue destruction. Advanced diagnostic methods, including 16S rRNA gene sequencing and whole-genome sequencing of tissue samples, finally identified Wohlfahrtiimonas chitiniclastica as the causative agent. This rare Gram-negative bacterium, typically associated with fly larvae and opportunistic human infections, was confirmed, highlighting the challenges in diagnosing unusual pathogens in chronic wounds.
Key note: Persistent non-healing wounds require thorough investigation using advanced molecular diagnostics, especially when conventional methods fail.