Classroom Dust Microbiome-Metabolome Signatures and Ocular Health in Students: Cross-sectional Associations with Putative Pollutant-Transformation and Microbial Functional Profiles.

Ocular irritation and tear-film instability are common among school-aged children, yet the microbial and chemical features of classroom dust associated with these outcomes remain poorly characterized. We conducted a cross-sectional multi-omics study in 32 classrooms from eight Indonesian junior high schools, integrating shotgun metagenomics and untargeted LC-MS metabolomics of settled dust with ocular symptoms and tear film break-up time (TFBUT) from 380 students. Classrooms with a low prevalence of ocular irritation were enriched in Actinobacteriota such as Allosaccharopolyspora coralli, Saccharopolyspora dendranthemae, and Brevibacterium epidermidis (LDA > 2, P < 0.05, LEfSe), and in microbial pathways annotated for the degradation of aromatic pollutants and xenobiotics, including xylene, benzoate, toluene and polycyclic aromatic hydrocarbons (LDA > 2, P < 0.05). Consistent with this, classrooms with more stable tear film showed higher signals of metabolites consistent with aromatic-compound and xenobiotic transformation, including 4-hydroxyphenylpyruvic acid, the phthalate-degradation intermediate 4-hydroxyphthalate, 3-hydroxybenzoic acid and 4-hydroxycinnamic acid (q < 0.05), indicating potential microbial degradation of aromatic pollutants in these classrooms. Statistical interactions linked specific genera to these features (e.g. Brevibacterium with trans-cinnamate and p-hydroxyphenylacetic acid, and Sphingomonas with 3-hydroxyphenylacetic acid) in relation to TFBUT, and taxa such as Janibacter and Nocardioides co-occurred with multiple degradation intermediates. These signatures point to microbial pollutant-transformation potential as a candidate modifier of the indoor exposome, warranting longitudinal and mechanistic follow-up.