Probiotic Weissella cibaria LAB_Weis_Camel_L4 alleviates Escherichia coli-induced enteritis by inhibiting pathogen colonization and modulating gut microbiota

Panpan Tong^1*Wanjin Jin¹Mengfei Zhang¹Xueqin Lan¹Ying Huang¹Yixin Bai¹Yingchao Li¹Chenyang Shi¹Yaolong Song¹Lei Wang¹Yi Zhang¹Wei Zhang²Gulina Aishan³Mingyang Geng³Zhanqiang Su¹Jinxin Xie¹

• ¹Xinjiang Agricultural University, Ürümqi, China
• ²Nanjing Agricultural University, Nanjing, China
• ³Ili Kazakh Autonomous Prefecture General Animal Husbandry Station, Xinjiang Uighur Autonomous Region, China

Background: Pathogenic Escherichia coli (E. coli), a significant zoonotic pathogen, causes considerable economic losses worldwide by infecting neonatal animals and leading to enteric disease. The development of antimicrobial resistance and perturbations in ecological homeostasis increasingly undermine the therapeutic efficacy of conventional antibiotics. This study introduces a novel probiotic-based intervention, systematically assessing the therapeutic potential of the newly isolated Weissella cibaria LAB_Weis_Camel_L4 in a mouse model of E. coli-induced enteritis. Furthermore, it investigates the underlying mechanism through which this probiotic modulates intestinal homeostasis, focusing on the "microbiota–gut–immunity" pathway. Methods: In this study, the Weissella cibaria LAB_Weis_Camel_L4 was systematically isolated and identified, followed by a comprehensive in vitro evaluation of its probiotic properties, including growth kinetics, acid production, and tolerance to acidic pH and bile salts. Genomic analyses were performed to assess safety at the molecular level. An enteritis mouse model induced by pathogenic E. coli was then established to evaluate the in vivo safety and therapeutic efficacy of LAB_Weis_Camel_L4 through histopathological examination. Furthermore, 16S rRNA sequencing was performed to characterize alterations in gut microbiota composition following probiotic intervention. Results: A novel Weissella cibaria, LAB_Weis_Camel_L4, was identified and showed strong probiotic characteristics. In vitro assays revealed high gastrointestinal tolerance (survival rate > 80%) and significant antibacterial activity (inhibition zones ranging from 12.57 to 16.76 mm). Genomic analysis verified its safety, with no detectable antibiotic resistance or virulence-associated genes. In vivo studies demonstrated that LAB_Weis_Camel_L4 significantly decreased mortality in E. coli-infected mice (p < 0.01), mitigated intestinal inflammation, and suppressed pathogenic colonization by modulating gut microbiota composition, highlighting its therapeutic potential. Conclusions: Weissella cibaria LAB_Weis_Camel_L4 significantly attenuates E. coli-induced intestinal inflammation and promotes a mucosal barrier through dual mechanisms: inhibiting pathogen colonization and modulating the gut microbiota. Its potent microecological antagonistic activity and ability to maintain intestinal homeostasis position it as a promising probiotic candidate for antibiotic substitution.