Weissella cibaria CH2 is an exopolysaccharide (EPS) producing bacterium, isolated from cheese. Maximum EPS production (81.3%) was observed with sucrose at 20 °C. The CH2 strain was tolerant of simulated gastric juice (pH 3) with a 5.3% decrease in the viable count after 180 min, but not of pH 2. Similarly, no significant decrease in the viable count was observed in the presence of simulated intestinal juices (pH 8) and bile salts (0.3%) after 240 min. The CH2 strain showed good aggregation ability and antimicrobial activity against representative pathogenic bacteria that may promote the colonization of the CH2 strain in the gastrointestinal tract. Complete genome sequencing supplemented the experimental evidence as genes encoding for EPS production, gastrointestinal tolerance, and adhesion were observed in the CH2 genome. Genomic analysis also showed the presence of functional traits such as cholesterol reduction, β-galactosidase production, vitamin, and essential amino acid biosynthesis. The absence of transferable antibiotic resistance genes and virulence factors in the CH2 strain was further confirmed using genome sequencing. The present study highlights the potential of the CH2 strain for use as a probiotic.

魏氏菌CH2是一种从奶酪中分离出的胞外多糖（EPS）产生细菌。在20°C下用蔗糖观察到最大EPS产量（81.3％）。CH2菌株耐受模拟胃液（pH 3），在180分钟后存活数减少5.3％，但不耐受pH2。类似地，在存在模拟肠液的情况下，观察到存活率没有显着下降240分钟后（pH 8）和胆盐（0.3％）。CH2菌株对代表性的病原菌表现出良好的聚集能力和抗菌活性，可促进CH2菌株在胃肠道中的定殖。完整的基因组测序补充了实验证据，因为在CH2基因组中观察到了编码EPS产生，胃肠道耐受性和粘附的基因。基因组分析还显示了功能性状的存在，例如胆固醇降低，β-半乳糖苷酶的产生，维生素和必需氨基酸的生物合成。使用基因组测序进一步证实了CH2菌株中不存在可转移的抗生素抗性基因和毒力因子。本研究强调了CH2菌株用作益生菌的潜力。