Title : Invasive bloodstream infection caused by magnusiomyces capitatus: Case report with clinical review
Abstract:
We present the case of a 62-year-old incarcerated African American male with a history of coronary artery disease (CAD) post-stent placement, chronic obstructive pulmonary disease (COPD), and benign prostatic hyperplasia (BPH), recently diagnosed with acute myeloid leukemia (AML). The patient underwent induction chemotherapy with 7+3 (daunorubicin and cytarabine), followed by a period of prolonged pancytopenia.
Despite compliance with prophylactic anti-microbial regiment with Levofloxacin, Trimethoprim- sulfamethoxazole, Valacyclovir, and Posaconazole, this immunocompromised patient developed neutropenic fever 9 days after completion of induction chemotherapy. Neutropenic fever persisted despite escalation of antibiotics therapy with broad spectrum coverage. Blood cultures collected on day 1 of neutropenic fever were positive for Magnusiomyces capitatus, a rare opportunistic fungal pathogen with high mortality in immunocompromised patients, particularly those with myelosuppression.
Literature suggests common sites of Magnusiomyces capitatus dissemination include the lungs, central lines, and gastrointestinal tract. In this case, the patient demonstrated persistent fungemia, confirmed by positive Fungitell assay. The patient was transitioned to Amphotericin B and Voriconazole. Transthoracic echocardiogram showed no vegetations, and CT of the abdomen and pelvis revealed fecal loading without evidence of bowel thickening or rectal abscesses.
The Karius test identified Staphylococcus species (likely contamination) but no additional actionable pathogens. Despite antifungal therapy and supportive care, the patient continued to have high fevers up to 39.5°C. Repeat bone marrow biopsy showing persistent 80% blasts, and a second cycle of chemotherapy was carried out without successfully inducing remission. The patient elected transition to hospice comfort care.
This case highlights the challenges of managing disseminated Magnusiomyces capitatus in patients undergoing induction chemotherapy for AML. Early detection, aggressive antifungal therapy, source control, and treatment of comorbidities are critical for improving outcomes. Furthermore, this case underscores the importance of multidisciplinary collaboration in managing infectious complications in immunocompromised hosts.
