P487 Basidiobolus omanensis, an emerging pathogen to watch out for?

Abstract Poster session 1, September 21, 2022, 12:30 PM - 1:30 PM Introduction Basidiobolus species can be found in amphibian, reptile, lizard, insectivorous bat, and soil, as well as decaying vegetables, and fruits. Basidiobolus species infect both adults and children, with the majority of cases reported from the Middle East, including Oman. Basidiobolomycosis is a chronic subcutaneous infection of the trunk and limbs that typically manifests as subcutaneous or gastrointestinal lesions with only a few cases of systemic involvement. Basidiobolus haptosporus, B. heterosporus, B. magnus, B. meristosporus, B. microsporus, B. omanensis and B. ranarum are the seven species in the genus Basidiobolus. Four of these species have been linked to gastrointestinal infections in humans. Basidiobolus ranarum is the most commonly reported species from humans, followed by B. omanensis. We recently described B. omanensis as a novel species from a patient in Oman. It was isolated from a boy with type 1 diabetes who died as a result of basidiobolmycosis complications. Four more fatal human cases have been documented since then (unpublished data), but little is known about its role as a pathogen in humans. Objective The goal of this paper is to present four cases of basidiobolomycosis caused by B. omanensis in young children and adults, each with unique diagnostic and treatment challenges. Methods We collected four cases of basidiobolomycosis caused by B. omanensis from various tertiary hospitals in Oman. All identifications were based on ribosomal DNA gene sequencing of the internal transcribed spacers (ITS) and partial large subunit (LSU). The CLSI method was used for testing the antifungal drug susceptibility in vitro. Results We present four new cases of Basidiobolus infection in humans (two from children and two from adults). The underlying condition, site of infection, clinical presentation, treatment, and outcomes are all summarized in Table 1. Basidiobolus omanensis strains isolated from these cases were molecularly identified using (ITS and LSU) gene sequencing. The minimum inhibitory concentration (MIC) for amphotericin B (AMB) is 1 µg/ml, isavuconazole (ISC) is 4 µg/ml, itraconazole (ITC), posaconazole (PSC), and voriconazole (VRC) is > 16 µg/ml respectively. These were the first cases of the fungus B. omanensis ever diagnosed globally at various hospitals in Oman. All of the cases presented diagnostic and treatment challenges. Despite the atypical nature of the disease, clinical response was obtained following surgical excision and antifungal treatment, and the mortality rate among the four cases was 50%. Conclusion This new species may cause problems with identification and antifungal susceptibility, which is why clinicians should be aware of infections with uncommon mould species and consider DNA sequencing for confirmation. Any fungus can cause infection in an immunocompromised host and should never be dismissed as a contaminant out of hand.