A surprising diagnosis of paracoccidioidomycosis from routine bacterial culture of chronic finger lesions

November 5, 2025
Case Report
Nikita Jaggernauth, Juan Pineda-Reyes, Claire Zurlo, Devin M Weber, Matthew A Pettengill, Nathan P Wiederhold, Connie CaƱete-Gibas, Courtney E Comar
Pathogen:Paracoccidioides brasiliensis
Infection Type:Cutaneous infection
Pathogen Type:Fungus

Summary

An elderly female presented with chronic, non-healing finger lesions, initially suspected to be bacterial. Routine bacterial culture surprisingly revealed a dimorphic fungus. Further investigation, including histopathology and molecular testing, identified Paracoccidioides brasiliensis, leading to a diagnosis of cutaneous paracoccidioidomycosis. This case was complicated by the patient's comorbidities, which limited first-line therapeutic options. The diagnosis was unexpected, highlighting the importance of considering unusual pathogens in chronic skin infections, especially in patients with relevant epidemiological history.

Key note: Chronic, non-healing lesions, even when initially suggestive of bacterial etiology, warrant a broad diagnostic approach, including fungal cultures, particularly for dimorphic fungi.

DOI: 10.1128/asmcr.00133-25