Isolation and Screening of Lactic Acid Bacteria from the Gut of Forest Musk Deer for Probiotic Properties

This study aimed to isolate and select potential probiotic strains from the feces of healthy forest musk deer and to evaluate their in vitro probiotic characteristics. Twelve isolates were obtained and identified by cell morphology and bacterial 16S rDNA sequencing. Their survival under low pH and bile salt conditions, antagonistic activities against five pathogens (Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa PAO1, Salmonella enteritidis ATCC 13076 and Arcanobacterium pyogenes LSN3), auto-aggregation characteristics, hydrophobicity, antibiotic susceptibility and antibiotic resistance genotypes, and growth curves were evaluated. The results showed that five Lactiplantibacillus plantarum isolates and one Pediococcus acidilactici isolate survived at pH 4, or in 0.5% bile salt with survival rates of more than 88.5% and 87%, respectively. All of them inhibited the five pathogens with diameters of inhibition zones of 17.20-20.19 mm for E. coli ATCC 25922, S. aureus ATCC 25923, P. aeruginosa PAO1 and S. enteritidis ATCC 13076 and of 14.23-15.53 mm for A. pyogenes LSN3. They had similar auto-aggregation capacity (53.1%–56.2%) and surface hydrophobicity (52.9%–56.0%) to L. paracasei L22. They were resistant to streptomycin, ciprofloxacin and vancomycin, carried the vanX gene and rapidly grew; the optical density at 600 nm (OD600) reached 9.0 and 7.1 for L. plantarum and P. acidilactici from the gut of forest musk deer after 24 h incubation, respectively. Our findings demonstrated that these six isolates can be used as sources for the development of probiotic preparations intended for forest musk deer.