A Dual-Use Fungus: Systematic Review of Purpureocillium lilacinum as an Emerging Cause of Hyalohyphomycosis and a Source of Bioactive Secondary Metabolites

Purpureocillium lilacinum (formerly Paecilomyces lilacinus) is a hyaline filamentous fungus widely distributed in the environment, recognized both as an opportunistic human pathogen and as an agricultural biocontrol agent. Reports of hyalohyphomycosis caused by this species have increased, especially in immunocompromised patients, presenting diagnostic and therapeutic challenges due to antifungal resistance and difficulty in morphological identification. In parallel, the extensive use of the fungus and its secondary metabolites as biological control agents raises concerns regarding safety and the risk of human exposure. Thus, a systematic synthesis of the literature is necessary to integrate clinical, immunological, experimental, and applied evidence.