Invisible Passengers: Diversity and Risks of Fungi and Bacteria Transported via International Airport Passenger Footwear

Global movement of organisms, driven by human activity, facilitates the spread of pathogenic and invasive microorganisms across international borders. This study investigates the role of human footwear as a potential vector for microbial transmission by analyzing fungal and bacterial communities on passenger shoes arriving at Tallinn International Airport, Estonia. High-throughput sequencing of environmental DNA revealed significant seasonal and geographical influences on microbial community composition, with footwear harboring several high-risk human, plant, and animal pathogens, including those classified as priority threats by the World Health Organization. The findings underscore the urgent need for targeted biosecurity protocols at points of entry to mitigate microbial invasions and pathogen dispersal.