Clostridium zhoujianii sp. nov., a novel gram-negative species isolated from bat feces and its genetic characteristics.

A strictly anaerobic, rod-shaped bacterial strain, designated LP20ᵀ, was isolated from the intestinal contents of bats collected in Qiandongnan, China. Phylogenetic analysis of the 16 S rRNA gene revealed that strain LP20ᵀ shared its highest similarity with Clostridium paraputrificum ATCC 25780ᵀ (98.10%), a value below the accepted threshold for species delineation. Whole-genome sequencing further supported its taxonomic novelty, with ANI, dDDH, and AAI values to the closest relatives all falling well below species-level cutoffs. Strain LP20ᵀ exhibited unusual Gram-stain-negative morphology, grew optimally at 30–37℃ and pH 7.0–8.0, and possessed distinctive fatty acid and polar lipid profiles, including the presence of an unidentified aminophospholipid. Phenotypic assays revealed several metabolic and enzymatic traits that differentiated LP20ᵀ from its closest phylogenetic neighbors. 16 S rRNA amplicon sequencing and metagenomic screening confirmed the presence of this species in multiple bat hosts, suggesting a wider distribution within bat gut microbiomes. Functional genomic analysis indicated enrichment of genes involved in carbohydrate metabolism and a limited antibiotic resistance profile. Based on polyphasic evidence, strain LP20ᵀ represents a novel species within the genus Clostridium, for which the name Clostridium zhoujianii sp. nov. is proposed. The type strain is LP20ᵀ (= JCM 37970ᵀ = GDMCC 1.5627ᵀ).