United States Department of Agriculture/Agricultural Research Service, Southern Plains Agricultural Research Center, College Station, TX 77845, USA.
Folia Microbiol (Praha). 2012 Jul;57(4):253-8. doi: 10.1007/s12223-012-0119-4. Epub 2012 Apr 20.
Strategies are sought to reduce intestinal colonisation of food-producing animals by Campylobacter jejuni, a leading bacterial cause of human foodborne illness worldwide. Presently, we tested the antimicrobial activity of hydrolysable-rich blackberry, cranberry and chestnut tannin extracts and condensed tannin-rich mimosa, quebracho and sorghum tannins (each at 100 mg/mL) against C. jejuni via disc diffusion assay in the presence of supplemental casamino acids. We found that when compared to non-tannin-treated controls, all tested tannins inhibited the growth of C. jejuni and that inhibition by the condensed tannin-rich mimosa and quebracho extracts was mitigated in nutrient-limited medium supplemented with casamino acids. When tested in broth culture, both chestnut and mimosa extracts inhibited growth of C. jejuni and this inhibition was much greater in nutrient-limited than in full-strength medium. Consistent with observations from the disc diffusion assay, the inhibitory activity of the condensed tannin-rich mimosa extracts but not the hydrolysable tannin-rich chestnut extracts was mitigated by casamino acid supplementation to the nutrient-limited medium, likely because the added amino acids saturated the binding potential of the condensed tannins. These results demonstrate the antimicrobial activity of various hydrolysable and condensed tannin-rich extracts against C. jejuni and reveal that condensed tannins may be less efficient than hydrolysable tannins in controlling C. jejuni in gut environments containing high concentrations of amino acids and soluble proteins.
人们寻求各种策略以减少空肠弯曲菌（一种导致全球食源性疾病的主要细菌）对食用动物肠道的定植。目前，我们通过在补充有氨基酸的情况下使用圆盘扩散试验，测试了水解单宁丰富的黑莓、越橘和栗子单宁提取物以及浓缩单宁丰富的金合欢、荆豆和高粱单宁（均为 100mg/ml）对空肠弯曲菌的抗菌活性。我们发现，与未用单宁处理的对照相比，所有测试的单宁都抑制了空肠弯曲菌的生长，而在补充有氨基酸的营养有限培养基中，浓缩单宁丰富的金合欢和荆豆提取物的抑制作用有所减轻。在肉汤培养物中进行测试时，栗和金合欢提取物都抑制了空肠弯曲菌的生长，而在营养有限的培养基中抑制作用比在完全营养培养基中大得多。与圆盘扩散试验的观察结果一致，浓缩单宁丰富的金合欢提取物的抑制活性，但水解单宁丰富的栗提取物的抑制活性，在补充氨基酸到营养有限的培养基中时会减弱，这可能是因为添加的氨基酸使浓缩单宁的结合潜力饱和。这些结果表明，各种水解单宁和浓缩单宁丰富的提取物对空肠弯曲菌具有抗菌活性，并表明在含有高浓度氨基酸和可溶性蛋白质的肠道环境中，浓缩单宁可能不如水解单宁有效地控制空肠弯曲菌。
