Exophiala Bloodstream Infections in Humans—A Narrative Review

TL;DR

This paper reviews rare but severe Exophiala bloodstream infections in humans, focusing on patient characteristics, treatment responses, and mortality.

Contribution

The study provides a comprehensive review of Exophiala fungemia cases, highlighting clinical features and treatment outcomes.

Findings

Central venous catheters were the main risk factor in most cases.

Voriconazole was the most commonly used and effective antifungal treatment.

Overall mortality was 34.4%, with 25% directly caused by the infection.

Abstract

Background: Exophiala spp. are dematiaceous fungi with opportunistic pathogenic potential and a widespread environmental presence. Clinical cases of Exophiala spp. fungemia are uncommon. Although rarely encountered in the general population, these organisms are increasingly reported in immunocompromised individuals or those with complex underlying health conditions. Objectives: This review seeks to examine all documented human cases of Exophiala spp. fungemia, with particular focus on aspects such as epidemiology, microbiological features, resistance patterns, therapeutic approaches and associated mortality rates. Methods: A narrative review was conducted using data sourced from the PubMed/MedLine and Scopus databases. Results: A total of 19 articles described infections in 32 patients involving Exophiala spp. fungemia. The mean patient age was 49.2 years, and 65.6% were male. Central venous catheters emerged as the leading predisposing factor (96.9%). Fever represented the most frequent clinical presentation (50%), followed by organ dysfunction (21.9%). The yeast generally demonstrated susceptibility to voriconazole and itraconazole. Voriconazole was also the most frequently administered antifungal (62.5%), followed by amphotericin (31.3%) and micafungin (28.1%). Overall mortality reached 34.4%, with 25% of deaths specifically caused by the infection. Conclusions: Given the potential of Exophiala spp. to cause severe fungemia, healthcare professionals, particularly clinicians and microbiologists, should consider this pathogen in the differential diagnosis when black yeast is detected in blood cultures, especially in patients with immunodeficiency or significant comorbidities, to ensure timely and accurate identification.

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