Coccidioides Fungemia in Central California: A 10-Years Experience

Abstract

Background: Coccidioides fungemia is an uncommon but severe manifestation of disseminated coccidioidomycosis, associated with high mortality. Despite high endemicity in California's San Joaquin Valley, recent data from this region are limited. This study aims to describe the clinical characteristics, risk factors, and outcomes of patients with Coccidioides fungemia at a Central California tertiary care center.

Methods: We conducted a retrospective review of patients diagnosed with Coccidioides fungemia between 2015 and 2025 at Community Regional Medical Centers (CRMC) in Fresno, California. Data were collected from microbiology database and medical charts, including demographics, clinical presentation, diagnostics, treatment, and outcomes. Cases were classified based on EORTC/MSG criteria for disseminated fungal infections.

Results: Eleven patients with C. immitis fungemia were identified. The mean age was 40 years, and 64% were male. Risk factors included advanced HIV/AIDS (3), autoimmune disease requiring corticosteroids or immunosuppressants (4), diabetes with ESRD (1), chronic alcohol use (1) and pregnancy (1). One patient had no identifiable immunosuppressive condition. Miliary pulmonary involvement and extrapulmonary dissemination occurred in 64% of cases, with multiple organ involvement in more than half. All patients had positive cultures from additional sites, including respiratory, CSF, skin, peritoneal, and reproductive tissues. Routine blood cultures were positive in only 3 patients; the remainder required fungal-specific cultures. Time to culture positivity ranged from 5 to 27 days. Despite severe presentations, over half received initial fluconazole monotherapy, and none were treated with dual antifungal therapy. Overall mortality was 91%, with 50% dying within 7 days and 80% within 30 days of documented fungemia. Most cases (9/11) represented new-onset acute infections.

Conclusions: Coccidioides fungemia remains a rare but ominous complication of disseminated coccidioidomycosis, even in highly endemic areas. It appears to reflect fulminant, acute infection with high fungal burden and multiorgan dissemination. The diagnostic delay associated with routine cultures and the underutilization of aggressive antifungal therapy may contribute to poor outcomes. Increased clinical vigilance, early use of fungal-specific diagnostics, and prompt initiation of amphotericin B based treatment may improve prognosis in high-risk populations.

Keywords: Coccidioides; Coccidioides immitis; Disseminated coccidioidomycosis; Fungemia; Immunocompromised; San Joaquin Valley.