A rare case of invasive necrotizing myositis of the thigh caused by Basidiobolus ranarum: a multi-pronged approach to successfully managing a near-fatal polybacterial mycotic infection

Summary

A 46-year-old man developed a severe, spreading infection of his thigh muscle caused by a rare fungus called Basidiobolus ranarum, likely from an insect bite years earlier that was neglected. The infection became life-threatening when bacteria also invaded the tissue, causing widespread muscle death and bloodstream infection. Doctors treated him with multiple antifungal medications, antibiotics, surgery, and eventually had to amputate his leg to save his life. After six weeks of intensive care combining several medications including potassium iodide and extended oral antifungal therapy, the wound finally healed.

Background

Basidiobolomycosis is a rare fungal infection typically presenting as subcutaneous lesions in warm tropical regions. Deep tissue invasion with necrotizing myositis is uncommon, particularly in immunocompetent patients. This case represents an unusually severe manifestation complicated by secondary bacterial sepsis.

Objective

To report a rare case of invasive necrotizing myositis of the thigh caused by Basidiobolus ranarum in an immunocompetent patient and describe the multi-pronged therapeutic approach required for managing this life-threatening polybacterial mycotic infection.

Results

Basidiobolus ranarum was identified morphologically and by culture with characteristic zygospores and ballistospores. The patient underwent multiple surgical debridements and trans-femoral amputation. Treatment with amphotericin B, voriconazole, Lugol’s iodine, and prolonged itraconazole resulted in wound healing and infection eradication after six weeks.

Conclusion

Early recognition of fungal infection through KOH microscopy is critical when bacterial antibiotic resistance is encountered. A multipronged approach combining dual antifungal agents, potassium iodide, aggressive surgical debridement, and antibiotics can successfully manage severe Basidiobolomycosis, though early intervention may prevent limb amputation.
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