Efficacy of Zinc Pyrithione As A Novel Anti-Bacterial Coating Agent

Zinc pyrithione (ZPT) is used to prevent microbial degradation and deterioration of manufacturing starting materials such as plastics, polymers, and latexes. The main objective of this study was to evaluate the anti-bacterial properties of ZPT. Currently, there is insufficient data on the effect of ZPT on viability of commonly encountered bacterial pathogens. We tested the efficacy of ZPT manufactured in the form of film rolls as an anti-bacterial protective layer by using the ASTM–recommended protocol on growth of Enterococcus faecalis and Escherichia coli. The bacterial cultures were added to three materials provided by Cao Inc. containing either the base with no active ingredient, ZPT-A, or different amounts of active ingredient, ZPT-B (2.5%) and ZPT-C (5%). Following overnight incubation, bacterial growth was assessed by counting their colony forming units (CFUs). Growth of both E. faecalis and E. coli were strongly inhibited by ZPT-B and ZPT-C relative to growth on the control ZPT-A. Inhibition of E. faecalis was close to complete by ZPT-B and ZPT-C while E. coli growth was inhibited by greater than 95% in a dose dependent manner. This is the first report of zinc pyrithione, here in the form of thin film, inhibiting growth of common bacterial pathogens. ZPT rolls therefore show promise as an effective antibacterial layer for use as a protective barrier, for example on door handles and counters, from clinical to global public health settings.