Tenea Gabriela N, Angamarca Evelyn, Olmedo Daniela
Biofood and Nutraceutics Research and Development Group, Faculty of Engineering in Agricultural and Environmental Sciences, Technical University of the North, Av. 17 de Julio s-21. Barrio El Olivo, Ibarra 100150, Ecuador.
Antibiotics (Basel). 2022 Jan 25;11(2):154. doi: 10.3390/antibiotics11020154.
The occurrence of multidrug-resistant pathogens in the food chain causes health problems in humans, thus, research for novel antimicrobials to combat their growth is of interest. This study evaluates the antimicrobial potential of several combinations of peptide-protein extracts (PCs) consisting of peptide extracts from three native probiotic strains, UTNGt2, UTNGt28, and UTNGt21A, alone or in combination with EDTA (ethylenediaminetetraacetic acid) against multidrug-resistant ATCC1026 and UTNB3Sm1. Based on the antimicrobial assay, among the 19 tested PCs, two (PC11 and PC17) produced a greater zone of inhibition against both pathogens in vitro. Time-killing assays indicated the rapid death of after exposure to PC11 and PC17, while was rapidly inhibited by PC11 and PC1 (UTNGt2 only), suggesting that the inhibitory action is pathogen and dose-dependent of a particular molecule present in the extract. A marginal inhibitory effect was observed when the peptides were combined with EDTA. Transmission electron microscopy (TEM) revealed the structural membrane damage of both target strains upon interaction with individual peptide extracts. Different degrees of cell deformation, condensed cytoplasm, membrane blebbing, and ghost cell formation with visibly broken cell walls were observed in . Likewise, the separation of the cytoplasmic membrane from the outer membrane, ghost cells, along with ovoid and deformed cells with undulated cell walls were observed for . Furthermore, scanning electronic microscopy (SEM) analysis revealed different wrinkled and deformed cells covered by debris. A leakage of aromatic molecules was detected for both pathogens, indicating that PCs disrupted the cell wall integrity, inducing cell death. Given their inhibitory action and capacity to induce damage of the cytoplasmic membrane, the selected PCs may serve to slow bacterial growth in vitro; further research is required to prove their efficiency ex vitro to battle against food poisoning and subsequent human infection.
食物链中多重耐药病原体的出现给人类健康带来了问题，因此，研究新型抗菌剂以对抗其生长备受关注。本研究评估了由三种天然益生菌菌株UTNGt2、UTNGt28和UTNGt21A的肽提取物单独或与乙二胺四乙酸（EDTA）组合而成的几种肽 - 蛋白质提取物（PCs）对多重耐药的ATCC1026和UTNB3Sm1的抗菌潜力。基于抗菌试验，在19种测试的PCs中，有两种（PC11和PC17）在体外对两种病原体产生了更大的抑菌圈。时间 - 杀菌试验表明，暴露于PC11和PC17后细菌迅速死亡，而PC11和PC1（仅UTNGt2）能迅速抑制细菌生长，这表明抑制作用是病原体依赖性的，且取决于提取物中特定分子的剂量。当肽与EDTA组合时观察到了轻微的抑制作用。透射电子显微镜（TEM）显示，与单个肽提取物相互作用后，两种目标菌株的结构膜均受到损伤。在菌株中观察到了不同程度的细胞变形、细胞质浓缩、膜泡化以及细胞壁明显破裂的空壳细胞形成。同样，在菌株中观察到了细胞质膜与外膜分离、空壳细胞以及细胞壁呈波浪状的卵形和变形细胞。此外，扫描电子显微镜（SEM）分析显示，细胞出现不同程度的皱纹和变形，并被碎片覆盖。两种病原体均检测到芳香族分子泄漏，表明PCs破坏了细胞壁完整性，导致细胞死亡。鉴于其抑制作用和诱导细胞质膜损伤的能力，所选的PCs可能有助于在体外减缓细菌生长；需要进一步研究以证明其在体外对抗食物中毒及后续人类感染的有效性。
