[Objective] The purpose of this research was to analyze the Bacillus species, cellulose decomposition, antimicrobial activity and antibiotic resistance in giant panda intestines. [Methods] Bacillus was isolated based on the resistance of high temperature, then to construct the phylogenetic tree with 16S rRNA gene sequences. Hydrolyzed circle on the cellulose-congo red medium was measured to detect the cellulose decomposition. The oxford cup method was adopted to examine the bacteriostatic ability and then we analysed the relationship between the bacteriostatic ability and phylogenetic tree by software. The distribution regularity of Bacillus antibacterial peptides was detected by PCR. At last, susceptibility testing was put into use to detect the antibiotic resistance of Bacillus. [Results] Twenty-one strains was isolated and divided into 6 categories. All of the strains are able to decompose the cellulose on different levels by measuring the hydrolysis circle diameter. Most strains can inhibit the enteric pathogens obviously. Cluster analysis shows that the antibacterial ability is relevant to gene classification based on 16S rRNA gene in some cases. Susceptibility testing shows that most Bacillus strains are sensitive to common antibiotics, but a few strains are still resistant to the antibiotics. [Conclusion] The Bacillus strains isolated in giant panda intestines are abundant and able to decompose cellulose. The metabolic product of the antimicrobial peptide gene contained in all of 21 Bacillus strains can significantly inhibit three kinds of enteric pathogens. The Bacillus are sensitive to common antibiotics which is helpful to standardize clinical medicine.
