Two different types of condensed tannins (CTs), which were extracted and purified from tilia (Tilia L.) and black locust (Robinia pseudoacacia), were studied and tested against two kinds of bacteria, including Gram-negative and Gram-positive, avian pathogenic E. coli (APEC) and Staphylococcus epidermidis (S. epidermidis) respectively, by minimal bactericidal concentrations (MBCs) and scanning electron microscopy (SEM). Both CT extracts were significantly effective (p ≤ 0.05) at MBCs of 5-10 mg CT/ml against APEC (Gram-negative), and at 1.25-5 mg CT/ml on S. epidermidis (Gram-positive). This indicated that the CTs were more potent against the Gram-positive than the Gram-negative bacteria. Further, SEM revealed that CTs caused mainly morphological deformations of the bacterial cells and some conjoined cell growth.

中文翻译：

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使用扫描电子显微镜评估浓缩单宁提取物的抗病原作用

研究了从椴树 (Tilia L.) 和刺槐 (Robinia pseudoacacia) 中提取和纯化的两种不同类型的缩合单宁 (CTs)，并针对两种细菌进行了研究和测试，包括革兰氏阴性和革兰氏阳性，禽类通过最小杀菌浓度 (MBC) 和扫描电子显微镜 (SEM) 分别检测致病性大肠杆菌 (APEC) 和表皮葡萄球菌 (S.epidermidis)。两种 CT 提取物在 5-10 mg CT/ml 的 MBC 对 APEC（革兰氏阴性）和 1.25-5 mg CT/ml 对表皮葡萄球菌（革兰氏阳性）均显着有效（p ≤ 0.05）。这表明 CTs 对革兰氏阳性菌比对革兰氏阴性菌更有效。此外，SEM 显示 CT 主要引起细菌细胞的形态变形和一些联合细胞生长。