Evaluation ofCRS 33 to therapeutic effects on a murine model of-induced endometritis.

Abstract

INTRODUCTION: Bovine endometritis is a common postpartum uterine disease in dairy cows that is traditionally treated with antibiotics. However, excessive antibiotic use can lead to antimicrobial resistance and treatment failure.CRS33, a novel probiotic strain isolated from the uterus of a healthy cow, exhibits strong antibacterial potential. This study aimed to investigate the probiotic characteristics ofCRS33 through whole-genome sequencing and to evaluate its anti-inflammatory effects in a mouse model of-induced endometritis. METHODS: Whole-genome sequencing was performed to identify genes related to antibacterial, anti-inflammatory, and immune-regulatory activities, and to confirm the absence of antibiotic resistance and virulence genes. Female mice were induced withendometritis and treated withCRS33 at a dose of 1 &#xd7; 10CFU/mL. Uterine morphology, wet weight index, inflammatory cell infiltration, cytokine levels (IL-6, IL-1&#x3b2;, IL-8, TNF-&#x3b1;), and uterine microbiota composition were analyzed. RESULTS: Genomic analysis revealed thatCRS33 contains multiple functional genes related to antimicrobial, anti-inflammatory, and immune-modulatory pathways and lacks antibiotic resistance or pathogenic determinants. Treatment withCRS33 significantly alleviated uterine inflammation, reduced the wet weight index (< 0.05), and improved histopathological lesions. It also decreased pro-inflammatory cytokine levels and inflammatory cell infiltration, while enhancing microbial diversity and increasing the abundance of beneficial bacterial taxa. DISCUSSION: CRS33 demonstrates strong anti-inflammatory and microbiota-regulating properties in-induced endometritis, highlighting its potential as a safe and effective probiotic alternative to antibiotics. Further validation in dairy cows is warranted to confirm its therapeutic potential under practical conditions.