Here, we report a novel approach to improve the anti-Clostridium perfringens activity of the leaderless two-peptide enterocin 14 (EntDD14), produced by Enterococcus faecalis 14. This strategy consists of loading EntDD14 onto alginate nanoparticles (Alg NPs), which are made of a safe polymer. The resulting formulation (EntDD14/Alg NPs) was able to reduce up to four times the minimum inhibitory concentration (MIC) of EntDD14 against C. perfringens pathogenic strains isolated from a chicken affected by necrotic enteritis (NE). Interestingly, this formulation remained active under conditions mimicking the human and chicken gastric tract. Assays conducted to establish the impact of this formulation on the intestinal epithelial cell line Caco-2 and the human colorectal adenocarcinoma cell line HT29 revealed the absence of cytotoxicity of both free-EntDD14 and EntDD14 loaded onto the alginate nanoparticles (EntDD14/Alg NPs) against the aforementioned eukaryotic cells, after 24 h of contact. Notably, EntDD14 and EntDD14/Alg NPs, both at a sub-inhibitory concentration, affected the expression of genes coding for clostridial toxins such as toxin α, enteritis B-like toxin, collagen adhesion protein and thiol-activated cytolysin. Further, expression of these genes was significantly down-regulated following the addition of EntDD14/Alg NPs, but not affected upon addition of EntDD14 alone. This study revealed that adsorption of EntDD14 onto Alg NPs leads to a safe and active formulation (EntDD14/Alg NPs) capable of affecting the pathogenicity of C. perfringens. This formulation could therefore be used in the poultry industry as a novel approach to tackle NE.

在这里，我们报告了一种提高由粪肠球菌 14 产生的无前导二肽肠菌素 14 (EntDD14) 的抗产气荚膜梭菌活性的新方法。该策略包括将 EntDD14 负载到藻酸盐纳米粒子 (Alg NPs) 上，该纳米粒子由一种安全的聚合物。所得制剂（EntDD14/Alg NP）能够将 EntDD14 对产气荚膜梭菌的最小抑制浓度 (MIC) 降低多达四倍从受坏死性肠炎 (NE) 影响的鸡中分离出的致病菌株。有趣的是，该制剂在模仿人和鸡胃道的条件下仍然保持活性。为确定该制剂对肠上皮细胞系 Caco-2 和人结直肠腺癌细胞系 HT29 的影响而进行的测定表明，游离的 EntDD14 和负载到藻酸盐纳米粒子 (EntDD14/Alg NPs) 上的 EntDD14 均不存在细胞毒性。上述真核细胞，接触24小时后。值得注意的是，EntDD14 和 EntDD14/Alg NP 在亚抑制浓度下都会影响编码梭菌毒素（如 α 毒素、B 型肠炎样毒素、胶原粘附蛋白和硫醇激活溶细胞素）的基因表达。更远，添加 EntDD14/Alg NP 后，这些基因的表达显着下调，但单独添加 EntDD14 时不受影响。这项研究表明，EntDD14 吸附到 Alg NP 上会形成一种安全且活性的制剂（EntDD14/Alg NP），能够影响细菌的致病性。产气荚膜梭菌。因此，该配方可在家禽业中用作解决 NE 的新方法。