From antimicrobial activity to microbial ecology: Untreated and treated wood surfaces shape bacterial survival and community diversity in indoor environments

• Untreated wood supports higher bacterial diversity and richer communities. • S. epidermidis survives on untreated wood; P. aeruginosa loses culturability. • Wood type and surface treatments can strategically shape surface microbiomes. • Findings motivate the development of hygienic and probiotic wood material designs. Wood, beyond its structural and aesthetic qualities, exhibits antibacterial activity that may influence microbial persistence and transmission. However, bacterial adherence to wood, particularly in interior materials, remains understudied. Understanding the dynamics of bacterial adhesion, survival, and transmission requires a combination of laboratory and field research, especially given the variability of microbial diversity under real-use conditions. This two-part study has examined bacterial survival on untreated and treated wood surfaces. First, in vitro experiments assessed the adherence and viability of two model bacteria, Staphylococcus epidermidis and Pseudomonas aeruginosa . Secondly, public exposure trials evaluated bacterial colonization under real-world conditions using contact plates for sampling and 16S rRNA sequencing to analyze microbial diversity, including Shannon index and ASV richness. Metrics were assessed via linear mixed models. In vitro, P. aeruginosa cell counts declined rapidly across all materials, with viability staining suggesting many cells entered a viable but non-culturable state. In contrast, S. epidermidis showed enhanced survival on untreated wood, particularly on pine. Public trials mirrored these findings: untreated wood supported higher species richness, colony-forming units, and bacterial viability, whereas treated surfaces consistently exhibited lower microbial diversity and Shannon index values. Overall, these results demonstrate that untreated wood fosters more diverse and resilient microbial communities than treated wood, suggesting that surface treatment alters wood’s ecological role in shaping bacterial persistence. These findings highlight the importance of material selection in environments where microbial interactions impact hygiene, durability, and human health.