The Bacillus subtilis group comprises species known for their ability to produce a wide variety of antimicrobial peptides. This work focuses on bacilysin, a broad-spectrum active dipeptide, and its prevalence in the B. subtilis group. In silico genome analysis of strains from Bacillus amyloliquefaciens, Bacillus velezensis, Bacillus licheniformis, Bacillus pumilus and B. subtilis subspecies inaquosorum, spizizenii and subtilis revealed that the bacilysin gene cluster is present in all species except for B. licheniformis. This observation was corroborated by PCR detection of the bacilysin genetic determinants on a collection of 168 food and environmental strains from the B. subtilis group. Phylogenetic analyses also demonstrated that the bacilysin gene cluster sequence showed more than 80 % identity within each species of the B. subtilis group. An in vitro screening of the strain collection was performed against foodborne pathogens. Twenty-three strains were selected for their ability of their Cell-Free Supernatant to inhibit foodborne pathogens. After an ammonium sulphate precipitation of their supernatant, eight strains, all belonging to B. velezensis, exhibited antimicrobial activity against Gram-negative pathogens. Using Ultra High Performance Liquid Chromatography - Mass Spectrometry, the presence of bacilysin was confirmed in these eight precipitates. These findings provide evidence that bacilysin is a major player in the antagonistic activity of B. velezensis against Gram-negative foodborne pathogens.

该枯草芽孢杆菌组包括用于它们产生多种抗微生物肽的能力已知的物种。这项工作的重点是杆菌肽，一种广谱活性二肽，及其在枯草芽孢杆菌组中的流行。来自解淀粉芽孢杆菌、贝雷兹芽孢杆菌、地衣芽孢杆菌、短小芽孢杆菌和枯草芽孢杆菌亚种inaquosorum、spizizenii和枯草芽孢杆菌的菌株的计算机基因组分析显示，除了地衣芽孢杆菌外，所有物种都存在杆菌素基因簇。. 这一观察结果通过对来自枯草芽孢杆菌组的 168 种食物和环境菌株的聚合酶链反应检测证实。系统发育分析还表明，在枯草芽孢杆菌组的每个物种内，杆菌肽基因簇序列显示出超过 80% 的同一性。一种体外筛选菌种保藏的是对食源性致病菌进行。选择了 23 种菌株，因为它们的无细胞上清液具有抑制食源性病原体的能力。对其上清液进行硫酸铵沉淀后，8 个菌株均属于B. velezensis, 对革兰氏阴性病原体表现出抗菌活性。使用超高效液相色谱-质谱法，在这八种沉淀物中确认了杆菌肽的存在。这些发现证明杆菌肽是B. velezensis对抗革兰氏阴性食源性病原体的主要参与者。