The black aspergilli ( Aspergillus niger complex) and their role in human, animal, and plant diseases

SUMMARY The Aspergillus niger complex, also known as the black aspergilli or section Nigri , comprises a diverse group of filamentous fungi with wide-ranging ecological, industrial, and pathogenic significance. While traditionally associated with food spoilage and industrial fermentation, black aspergilli have emerged as opportunistic pathogens affecting humans, animals, and plants. This review provides a comprehensive synthesis of the taxonomy, ecology, pathogenicity, and antifungal resistance of the A. niger complex. Advances in phylogenetics and whole-genome sequencing have clarified the taxonomy of section Nigri , now comprising six core species in series Nigri . Clinically, A. niger complex is implicated in various conditions, including otomycosis, keratitis, cutaneous infections, onychomycosis, chronic pulmonary aspergillosis, and, less commonly, invasive aspergillosis. In animals, black aspergilli have been isolated from respiratory, cutaneous, and systemic infections, particularly in immunocompromised or stressed hosts. Plant pathogenicity is significant, with A. niger complex contributing to pre- and post-harvest spoilage and producing mycotoxins such as ochratoxin A and oxalic acid. The common finding of elevated minimum inhibitory concentrations (MICs) to triazoles, particularly in both environmental and clinical isolates, raises concern, with underlying mechanisms differing from those characterized in A. fumigatus . Reduced susceptibility is potentially driven by efflux pumps and environmental exposure to azole fungicides. Due to commonly higher MICs, antifungal therapy with itraconazole and isavuconazole may have reduced efficacy, and alternatives such as voriconazole or posaconazole should be considered, guided by susceptibility testing where available. This review emphasizes the need for a One Health approach to managing black aspergilli, integrating surveillance, diagnostics, and targeted interventions across human, veterinary, and agricultural sectors.