# The Probiotic Effects of Lactobacillus intestinalis Y10 Isolated From Feces of Wild Brown Rat (Rattus norvegicus)

## TL;DR

This study identifies a probiotic strain from wild rat feces that survives harsh conditions and inhibits harmful bacteria, showing potential for rodent-specific probiotic use.

## Contribution

The study characterizes Lactobacillus intestinalis Y10 as a novel probiotic candidate with strong survival and antimicrobial properties from wild rat feces.

## Key findings

- L. intestinalis Y10 showed 72.4% viability after 2 hours in acidic conditions (pH 2.5).
- The strain exhibited high hydrophobicity (93.80%) and auto-aggregation (81.68%), indicating strong mucosal adhesion.
- It demonstrated concentration-dependent antimicrobial activity against E. coli, P. aeruginosa, and S. aureus.

## Abstract

The gut microbiota of wild mice exhibits a significant correlation with their environmental adaptability, particularly highlighted by the dominance of Lactobacillus spp. This study evaluated the probiotic traits of Lactobacillus intestinalis Y10, a fecal isolate from Rattus norvegicus, through in vitro assays. The strain demonstrated two‐hour survival in acidic conditions (pH 2.5; 72.4% viability) and maintained viability under 0.3% bile salts for 24 h. It also showed high hydrophobicity index (93.80%) and auto‐aggregation percentage (81.68%), indicative of superior mucosal adhesion potential. Organic acid–mediated antimicrobial and antibiofilm activity of strain Y10 against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus subsp. aureus exhibited concentration dependence. Antibiotic susceptibility profiling identified sensitivity to cell wall–targeting agents (penicillin and cephalosporin) but resistant to antibiotics that inhibit nucleic acid synthesis and cytoplasmic membrane function, suggesting the possibility of clinical compatibility with fluoroquinolones or diaminopyrimidines for treatment of specific infections to minimize gut microbiota disruption. These findings position L. intestinalis Y10 as a promising candidate for rodent‐specific probiotic applications, combining environmental resilience with pathogen exclusion capabilities. Further in vivo validation and mechanistic studies are required to translate these traits into therapeutic interventions for gastrointestinal dysbiosis.