Aquatic Plastisphere as a Reservoir for Pathogenic and Antifungal-Resistant Fungi

High Resolution Image Download MS PowerPoint Slide Plastic pollution creates a globally distributed “plastisphere” microhabitat, yet its role in fostering antifungal resistance, a rapidly emerging One Health threat, remains poorly understood. Here, we tested whether aquatic plastic debris harbors potentially pathogenic fungi with antifungal resistance traits through combined shotgun metagenomics, culture-based validation, antifungal susceptibility testing, and isolate whole-genome sequencing. Diverse fungal assemblages were detected in the plastisphere from urban and peri-urban water bodies, including 32 FungAMR-curated pathogenic species, 13 of which are listed as WHO priority fungal pathogens. All 32 pathogenic species had contigs carrying at least one known resistance-conferring amino acid substitution, indicating widespread resistance potential across the detected pathogenic assemblage. Culture-based assays confirmed viable high-risk fungi, including Aspergillus fumigatus, Fusarium oxysporum, and Candida parapsilosis, with their isolates exhibiting multidrug-resistant phenotypes in MIC tests against 11 antifungal agents. Cross-substrate comparison further showed higher burdens of fungi carrying resistance-associated substitutions on microplastics than in bulk water. These findings indicate that the aquatic plastisphere potentially acts as a reservoir and dispersal vehicle for antifungal-resistant fungal pathogens, highlighting an overlooked dimension of plastic pollution with One Health relevance.