Rasooly Reuven, Molnar Adel, Do Paula, Morroni Gianluca, Brescini Lucia, Cirioni Oscar, Giacometti Andrea, Apostolidis Emmanouil
U.S. Department of Agriculture, Agricultural Research Service, Albany, CA 94710, USA.
Department of Chemistry and Food Science, Framingham State University, Framingham, MA, USA.
Pathogens. 2020 Feb 1;9(2):92. doi: 10.3390/pathogens9020092.
Bovine intramammary infections (IMIs) are the main cause of economic loss in milk production. Antibiotics are often ineffective in treating infections due to antimicrobial resistance and the formation of bacterial biofilms that enhance bacterial survival and persistence. Teat dips containing germicides are recommended to prevent new IMIs and improve udder health and milk quality. IMIs are often caused by staphylococci, which are Gram-positive bacteria that become pathogenic by forming biofilms and producing toxins. As a model for a teat dip (DIP), the BacStop iodine-based teat dip (DIP) was used. Witch hazel extract (whISOBAX (WH)) was tested because it contains a high concentration of the anti-biofilm/anti-toxin phenolic compound hamamelitannin. We found that the minimal inhibitory or bactericidal concentrations of DIP against planktonic cells increased up to 160fold in the presence of WH, and that DIP was 10-fold less effective against biofilm cells. While both DIP and WH are effective in inhibiting the growth of , only WH inhibits toxin production (tested for enterotoxin-A). Importantly, WH also significantly enhances the antibacterial effect of DIP against Gram-negative bacteria that can cause IMIs, like and . Put together, these results suggest that the antibacterial activity of DIP combined with WH is significantly higher, and thus have potential in eradicating bacterial infections, both in acute (planktonic-associated) and in chronic (biofilm-associated) conditions.
牛乳房内感染（IMIs）是牛奶生产中经济损失的主要原因。由于抗菌药物耐药性以及细菌生物膜的形成（生物膜可提高细菌的存活率和持久性），抗生素在治疗感染方面往往无效。建议使用含有杀菌剂的乳头药浴液来预防新的乳房内感染，并改善乳房健康和牛奶质量。乳房内感染通常由葡萄球菌引起，葡萄球菌是革兰氏阳性菌，通过形成生物膜和产生毒素而致病。作为乳头药浴液（DIP）的模型，使用了基于碘的BacStop乳头药浴液（DIP）。对金缕梅提取物（whISOBAX (WH)）进行了测试，因为它含有高浓度的抗生物膜/抗毒素酚类化合物金缕梅鞣质。我们发现，在存在金缕梅提取物的情况下，乳头药浴液对浮游细胞的最低抑菌浓度或杀菌浓度增加了160倍，并且乳头药浴液对生物膜细胞的效果降低了10倍。虽然乳头药浴液和金缕梅提取物都能有效抑制[细菌名称未给出]的生长，但只有金缕梅提取物能抑制毒素产生（针对肠毒素A进行测试）。重要的是，金缕梅提取物还显著增强了乳头药浴液对可引起乳房内感染的革兰氏阴性菌（如[细菌名称未给出]和[细菌名称未给出]）的抗菌作用。综上所述，这些结果表明，乳头药浴液与金缕梅提取物联合使用时的抗菌活性显著更高，因此在消除急性（与浮游菌相关）和慢性（与生物膜相关）条件下的细菌感染方面具有潜力。
