Antibacterial effects of condensed tannins on ruminant fecal bacteria.

摘要

A study was conducted to determine the antimicrobial activity of condensed tannins on ruminant fecal bacteria from dairy cattle using an in vitro system. Three Gram positive and four Gram negative bacterial species were selected from differential media for a comparison and were identified through genomic and biochemical analysis. The antimicrobial activity of plant condensed tannins was tested using the disc diffusion method. A small, round disc was placed in the center of a plate containing a bacterial species sample and a concentration of condensed tannin, kanamycin or a methanol control was added to saturate the disc. The zone of inhibition was measured to determine the antimicrobial activity of each type of condensed tannin on each bacterial species. The results suggest that condensed tannins have greater inhibition towards Gram positive than Gram negative bacterial species and that condensed tannins possess antibacterial properties against some ruminant fecal bacteria.