(653) Unusual Suspect: Case of Lomentospora Fungemia Highlighting Diagnostic and Therapeutic Challenges

Introduction: Lomentospora prolificans, formerly known as Scedosporium prolificans, is a highly virulent emerging opportunistic pathogen. Localized wound infections have been described in immunocompetent hosts mostly following trauma or surgery. However, disseminated infection is associated with significant morbidity and mortality, with mortality rates nearly 90%. Here we present a fatal case of disseminated L. prolificans infection in a patient with underlying acute myelogenous leukemia (AML).

Description: A 70-year-old female with AML on azathioprine presented to our hospital for planned chemotherapy with cytarabine and liposomal daunorubicin. On presentation, lab work revealed leukopenia with white blood cell count (1.5K/mcL) along with severe neutropenia and absolute neutrophil count (290/mcL). She was on acyclovir, posaconazole and ciprofloxacin for antimicrobial prophylaxis. During the hospital stay she developed febrile neutropenia. Imaging of the chest revealed left upper lobe ground-glass opacity and consolidation. Ciprofloxacin was discontinued and cefepime and vancomycin were initiated. Blood cultures grew mold. Posaconazole was switched to voriconazole to provide coverage for potential Fusarium fungemia. Amphotericin B was added as she had historically been unable to attain therapeutic level of voriconazole in the past. She was persistently fungemic with progressive shock and development of acute respiratory distress syndrome. The family elected to pursue comfort measures and she expired shortly after. Three days postmortem the mold on blood culture was identified as L. prolificans.

Discussion: L.prolificans is an emerging opportunistic pathogen which can cause life-threatening disseminated infection in immunocompromised hosts, specifically those with severe neutropenia. Treatment is challenging due to intrinsic resistance to most antifungals. Voriconazole combined with terbinafine has been shown to be somewhat effective. Due to the genetic variation of the enzyme CYP2C19, about 2-30% of the population are found to be rapid or ultra rapid metabolizers of voriconazole, limiting its effectiveness. This case emphasizes the need for new anti-fungal drugs effective against emerging pathogens