In this work, we studied the genomes and characterized some probiotic features of four S. macedonicus strains isolated from dairy environments in Italy that already had indicated some technological potential. The genomes of these strains were sequenced and used for genomic in silico studies. All strains were also evaluated for hemolytic activity, susceptibility to most commonly used antibiotics and probiotic potential, such as resistance to simulated gastrointestinal conditions, bile salts hydrolytic activity and adhesion ability to HT-29 human colorectal adenocarcinoma cells. Results revealed that one strain, namely S. macedonicus 211MA, was found to possess probiotic properties, such as resistance to simulated gastrointestinal conditions as well as adherence capability to human epithelial cells. In silico analyses revealed that S. macedonicus 211MA displayed the least number of single copy genes, genomic islands regions and gene content classified as virulence factors when compared to other S. macedonicus and S. gallolyticus strains. Moreover, the maximum gene content associated with bacterial stress response category and the presence of the opuCABCD operon, not detected in the other strains, were correlated with S. macedonicus 211MA capability to resist to low pH and to show higher adhesion to HT-29 human cells. This is the first report on the presence of opuCABCD operon in S. macedonicus and its possible relation with attachment ability and stress response.

在这项工作中，我们研究了四个S的基因组并鉴定了其益生菌的特征。从意大利的乳制品环境中分离出的马其顿菌株已经显示出一定的技术潜力。对这些菌株的基因组进行测序，并用于计算机基因组研究。还评估了所有菌株的溶血活性，对最常用抗生素的敏感性和益生菌潜力，例如对模拟胃肠道条件的抵抗力，胆盐水解活性和对HT-29人结肠直肠腺癌细胞的粘附能力。结果显示一种菌株，即马其顿酵母。211MA被发现具有益生菌特性，例如对模拟胃肠道条件的抵抗力以及对人上皮细胞的粘附能力。在计算机分析中，与其他马其顿酵母和解毒链球菌相比，马其顿酵母211MA显示出最少数量的单拷贝基因，基因岛区域和被分类为毒力因子的基因含量。此外，在其他菌株中未检测到的与细菌应激反应类别相关的最大基因含量和opuCABCD操纵子的存在与马其顿酵母相关。211MA具有抵抗低pH值和对HT-29人类细胞更高的粘附力的能力。这是在存在所述第一报告opuCABCD操纵子在S. macedonicus并与附着能力和应激反应的可能关系。