# Ligilactobacillus agilis LA-V4 Isolated from Vulture Fecal Isolate: A Novel Probiotic Candidate with Broad-Spectrum Antibacterial Activity

## TL;DR

A new probiotic from vulture feces shows strong antibacterial properties and could help prevent infections in animals.

## Contribution

Isolation and characterization of a novel probiotic strain from vulture feces with broad-spectrum antibacterial activity.

## Key findings

- Ligilactobacillus agilis LA-V4 inhibits pathogens like Salmonella and E. coli in agar well assays.
- The strain survives simulated gastrointestinal conditions with notable efficiency.
- Genome analysis shows no known virulence factors, supporting its safety profile.

## Abstract

Vultures are extraordinarily adapted to feed on carrion, providing them with a constant microbiologically hostile environment. This peculiar ecological position has influenced the evolution of their gut microbiota, potentially conferring its uncommon antimicrobial traits and resistance to stress. In this study, we report on the isolation and comprehensive characterization of a lactic acid bacterium strain, identified as Ligilactobacillus agilis, from vulture feces via 16S rRNA gene sequencing. This strain exhibited potent antagonistic activity against several clinically relevant bacterial pathogens, including Salmonella enterica Typhimurium (25.26 ± 0.26 mm), Escherichia coli (23.5 ± 0.88 mm), Staphylococcus aureus (23.1 ± 1.8 mm), and Listeria monocytogenes (24.88 ± 0.61 mm), as demonstrated by agar well diffusion assays. Remarkably, it also demonstrated considerable resilience in simulated gastrointestinal conditions, with survival rates of 52.5 ± 7.4% in artificial gastric juice and 61.1 ± 3.7% in intestinal fluids. Antimicrobial susceptibility profiling confirmed its sensitivity to a broad range of commonly used antibiotics, including gentamicin, streptomycin, clindamycin, and penicillin. Whole-genome sequencing further revealed a complete repertoire of core genes associated with genetic information processing, robust carbohydrate metabolism, and nutrient assimilation, underscoring its adaptability and probiotic potential. It is important to note that the analysis of the assembled genome against VFDB did not show the presence of any known virulence factor according to the given criteria, which is preliminary evidence of safety-related aspects that are to be followed with the help of guideline-based analyses. Taken together, the unique ecological origin and in vitro inhibitory activity against the tested pathogens, gastrointestinal robustness, genomic features, and safety credentials position this L. agilis strain as a promising probiotic candidate for mitigating enteric infections in animal production systems, warranting further functional validation and in vivo efficacy studies.