935. A Hospital Cluster of the Emerging Drug-resistant Yeast Saprochaete clavata

Abstract Background Saprochaete clavata, an ascomycetous yeast intrinsically resistant to echinocandins, is a rare yet emerging pathogen associated with invasive infections in immunosuppressed patients, particularly those with haematological malignancies. It is commonly misidentified as the closely-related S. capitata. Outbreaks have been associated with a high mortality rate of >50%, due in part to delayed diagnosis and resistance to commonly-used antifungals. Environmental source identification is challenging, although dishwashers and milk flasks have been implicated in previous hospital clusters. Methods We describe a cluster of five haematology-oncology patients with disseminated S. clavata infections between April 2020 and April 2021 following current or recent admissions to the same ward. Results All had prolonged (median=24 days, range=9-210) and profound immunosuppression from chemotherapy and/or stem cell transplantation for acute myeloid leukaemia (n=3) or lymphoma (n=2) at the time of culture positivity. Four were severely neutropaenic (median=0.08/mm3, range=0.01-0.26). Median patient age was 62 years (range=58-73). S. clavata was isolated from blood (n=3), urine (n=2), and liver tissue (n=1) samples. Whole genome sequencing of these isolates was performed to confirm the presence of an outbreak. All patients received empirical treatment with intravenous caspofungin before culture-guided therapy with intravenous liposomal amphotericin B +/- oral flucytosine. Two of the five patients died although both had advanced refractory malignancy. Detailed environmental sampling of fridges/freezers, drains, and vents in patient rooms and clean areas for handling or storage of food and medication failed to identify a clear point source despite isolation of multiple environmental organisms. No further cases have emerged after intensification of the cleaning regimen in these areas. Conclusion Our experience highlights the emerging threat of drug-resistant yeasts particularly in the immunocompromised. Management of such outbreaks requires a multidisciplinary approach incorporating antifungal stewardship, infection control, and environmental microbiology, alongside close clinical liaison between haemato-oncologists and infection specialists. Disclosures All Authors: No reported disclosures