 This study aimed to develop a sustainable, tannin-based alternative to silver-based and other existing antimicrobial solutions for hospital privacy curtains. Tannins from commercial trees were characterized and tested for their in vitro antibacterial activity against Staphylococcus aureus and Escherichia coli. Results indicated that hydrolyzable tannins had higher antibacterial efficacy than condensed tannins, but no difference in efficacy could be attributed to molecular weight or functional groups. Additionally, outer membrane disruption did not appear to play a role in antibacterial efficacy of tannins against E. coli. In a hospital field study, privacy curtains treated with hydrolyzable tannins showed a 60% reduction in total bacteria count after 8 weeks compared to their untreated counterparts. Furthermore, a follow-up laboratory study found that spraying the tannin-coated curtains with water increased their antibacterial effectiveness by several orders of magnitude. This article was authored by Petrie Whidson, Suthisalo, Klaus Niemela, and others. We are article.tv. Links in the description below.