Maestría en Investigación en Enfermedades Infecciosas, Facultad de Ciencias de la Salud, Grupo de Investigación en Ciencias Básicas y Aplicadas para la sostenibilidad - CIBAS, Universidad de Santander, Bucaramanga, Colombia.
Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Naturales y Agropecuarias, Grupo de Investigación en Ciencias Básicas y Aplicadas para la sostenibilidad - CIBAS, Universidad de Santander, Bucaramanga, Colombia.
PLoS One. 2020 Feb 13;15(2):e0229019. doi: 10.1371/journal.pone.0229019. eCollection 2020.
The development of new antimicrobial peptides has become an attractive alternative to conventional antibiotics due to the increasing rates of microbial drug resistance. Ib-M corresponds to a family of cationic synthetic peptides, 20 amino acids in length, that have shown inhibitory effect against the non-pathogenic strain Escherichia coli K-12. This work evaluated the antimicrobial potential of Ib-M peptides against the pathogenic E. coli O157: H7 using a reference strain and a clinical isolate. The Ib-M peptides showed antibacterial activity against both strains of E. coli O157: H7; the minimum inhibitory concentration of Ib-M peptides ranged from 1.6 to 12.5 μM and the minimum bactericidal concentration ranged from 3.7 to 22.9 μM, being Ib-M1 and Ib-M2 the peptides that presented the highest inhibitory effect. Time-kill kinetics assay showed a reduction of the bacterial population by more than 95% after 4 hours of exposure to 1xMIC of Ib-M1. Low cytotoxicity was observed in VERO cells with 50% cytotoxic concentration in the range from 197.5 to more than 400 μM. All peptides showed a random structure in hydrophilic environments, except Ib-M1, and all of them transitioned to an α-helical structure when the hydrophobicity of the medium was increased. In conclusion, these findings support the in vitro antimicrobial effect of Ib-M peptides against the pathogenic bacteria E. coli O157: H7 and prove to be promising molecules for the development of new therapeutic alternatives.
新型抗菌肽的开发已成为对抗传统抗生素的一种有吸引力的替代方法，因为微生物对抗生素的耐药率不断上升。Ib-M 对应于一类阳离子合成肽，长度为 20 个氨基酸，对非致病性大肠杆菌 K-12 具有抑制作用。本工作评估了 Ib-M 肽对致病性大肠杆菌 O157:H7 的抗菌潜力，使用了参考菌株和临床分离株。Ib-M 肽对两种大肠杆菌 O157:H7 菌株均具有抗菌活性；Ib-M 肽的最小抑菌浓度范围为 1.6 至 12.5 μM，最小杀菌浓度范围为 3.7 至 22.9 μM，Ib-M1 和 Ib-M2 是表现出最高抑制效果的肽。时间杀伤动力学试验显示，在暴露于 1xMIC 的 Ib-M1 4 小时后，细菌数量减少了 95%以上。在 VERO 细胞中观察到低细胞毒性，50%细胞毒性浓度范围为 197.5 至 400 μM 以上。所有肽在亲水环境中均呈现随机结构，除 Ib-M1 外，所有肽在介质疏水性增加时均转变为α-螺旋结构。总之，这些发现支持 Ib-M 肽对致病性大肠杆菌 O157:H7 的体外抗菌作用，并证明它们是开发新治疗方法的有前途的分子。
