Bacteriological characteristics and functional evaluation of newly identified Leuconostoc species: a novel probiotic for postoperative nutrition

Postoperative disruption of gut microbiota can lead to postsurgical infectious complications. Probiotics and synbiotics help reduce such risks, however, the optimal strains remain unclear. We aimed to evaluate the probiotic effects of Leuconostoc spp. ( L. suionicum MS009, L. mesenteroides MS061, and L. mesenteroides JCM6124) by determining their ability to grow in rice porridge, resistance to acid in simulated gastric fluid, and capacity to adhere to small intestinal epithelial cells (INT-407). Furthermore, these organisms were inoculated into rats, and metagenomic and metabolome analysis of cecal content and rectal feces were subsequently performed. Results showed that L. suionicum MS009 and L. mesenteroides MS061 grew well in rice porridge however exhibited poor acid resistance. L. suionicum MS009 demonstrated strong adhesion to intestinal cells. In rat models, administration of L. suionicum MS009 altered gut microbiota diversity, increased butyric acid, and enhanced immunoglobulin A levels in cecal contents. In conclusion, L. suionicum MS009 exhibited a higher capacity for growth in rice porridge and better adhesion to INT-407 cells than L. mesenteroides MS061. In rats, L. suionicum MS009 exerted immunoregulatory effects by altering the intestinal microbiome profile. Thus, rice porridge supplemented with L. suionicum MS009 as a probiotic may be a new diet for postoperative patients.