P288 Rhinocerebral mucormycosis due to Saksenaea vasiformis in a Sri Lankan patient: A rare fungal infection

POSTER SESSION 2, SEPTEMBER 22, 2022, 12:30 PM - 1:30 PM: BACKGROUND: Rhizopus, Rhizomucor, and Mucor species are renowned agents causing rhinocerebral mucormycosis; a disease with a high mortality rate. Saksenaea vasiformis is extremely rarely observed in this clinical entity. Minimal sporulation in common laboratory media might be responsible for the under-reporting of this organism. Here we present an uncommon case of rhinocerebral mucormycosis due to S. vasiformis. in a Sri Lankan patient with diabetes mellitus. CASE HISTORY: A 66-year-old female with diabetes mellitus was admitted with frontal headache, right-sided nasal block, anosmia, and right-side facial swelling. Examination revealed facial edema, maxillary sinus tenderness, and a white patch over the hard palate. Thick pus in postnasal space, growth in posterior tongue base, inflamed palate, and oropharynx, were revealed by rigid nasal endoscopy. She developed ophthalmoplegia along with right V and XII cranial nerve palsies irrespective of antibacterial therapy. Right side pansinusitis was observed in non-contrast computed tomography. She was subjected to right-side full house functional endoscopic sinus surgery with right orbital and optic nerve decompression. Irregular wide, ribbon-like, non-septate hyphae suggestive of Zygomycete fungi were observed in the direct microscopy of a deep surgical tissue sample and started with intravenous amphotericin B. After 5 days of incubation, the culture grew a zygomycetes-like mold with a lack of sporulation on Sabouraud dextrose agar, potato dextrose agar, and slide culture. However, the floating agar technique succeeded in producing flasks-shaped sporangium on a short sporangiophore with brown pigmented rhizoids after 14 days of incubation. The phenotypic features were suggestive of S. vasiformis. She was subjected to repeated debridement surgeries and treatment with amphotericin B was continued. She was clinically improving however, refractory hypokalemia along with hypernatremia interrupted her antifungal therapy resulting return of severe symptoms. Contrast-enhanced computed tomography of the brain revealed multiple micro-abscesses in the right temporal lobe. She clinically deteriorated and succumbed to the illness. DISCUSSION: Saksenaea vasiformis, a member of Mucorales, is largely bounded to cutaneous and subcutaneous infections. Rhino-orbital-cerebral infection is relatively uncommon and most of the reported cases were fatal irrespective of optimal therapy. Prompt diagnosis through fungal investigations of deep biopsy is mandatory. The delayed identification of this organism is attributed to its nature of poor sporulation on routine media. Special culture techniques and nutritionally deprived media enhance sporulation. Saksenaea vasiformis is usually sensitive to amphotericin B, high minimum inhibitory concentration has been reported though. CONCLUSION: Specific culture techniques should be used to induce sporulation if non-sporulating mucormycetes are encountered. Rhinocerebral mucormycosis is associated with a high degree of mortality even with effective antifungal therapy.