Project description:Clostridioides difficile infection (CDI), caused by strains producing toxin B (TcdB), poses a significant global health threat. While C. difficile exhibits substantial diversity, functional studies have focused on a limited number of isolates, overlooking other genomospecies within the genus. We describe five isolates from patients suspected of having CDI who tested negative for the PaLoc marker gene tcdC. Through genomic, proteomic, and phenotypic analyses, we demonstrate that they correspond to three novel toxin-producing species, designated as Clostridioides cryptodifficilis sp. nov., Clostridioides divergens sp. nov., and Clostridioides subdifficilis sp. nov. These species are distinguished by unique MALDI-ToF signatures, metabolic capabilities, and genomic and proteomic architectures, underscoring their clear taxonomic and functional divergence from C. difficile. They secrete functionally active TcdB7 or TcdB11, as demonstrated by cytotoxicity assays in cultured cells and in vivo using the mouse ileal loop model, implicating them in disease pathology, albeit with lower virulence than C. difficile. Our findings expand the known diversity of TcdB-producing Clostridioides and have direct implications for diagnostics, surveillance, and clinical management of diarrheal diseases.
Project description:Clostridioides difficile infection (CDI), caused by strains producing toxin B (TcdB), poses a significant global health threat. While C. difficile exhibits substantial diversity, functional studies have focused on a limited number of isolates, overlooking other genomospecies within the genus. We describe five isolates from patients suspected of having CDI who tested negative for the PaLoc marker gene tcdC. Through genomic, proteomic, and phenotypic analyses, we demonstrate that they correspond to three novel toxin-producing species, designated as Clostridioides cryptodifficilis sp. nov., Clostridioides divergens sp. nov., and Clostridioides subdifficilis sp. nov. These species are distinguished by unique MALDI-ToF signatures, metabolic capabilities, and genomic and proteomic architectures, underscoring their clear taxonomic and functional divergence from C. difficile. They secrete functionally active TcdB7 or TcdB11, as demonstrated by cytotoxicity assays in cultured cells and in vivo using the mouse ileal loop model, implicating them in disease pathology, albeit with lower virulence than C. difficile. Our findings expand the known diversity of TcdB-producing Clostridioides and have direct implications for diagnostics, surveillance, and clinical management of diarrheal diseases.
Project description:Isolation and characterization of two recently isolated Novosphingobium oxfordensis sp. nov. and Novosphingobium mississippiensis sp. nov. strains from soil, with LCMS and genome-based investigation of their glycosphingolipid productions
Project description:Strain SM1988T is a Gram-negative, aerobic, oxidase- and catalase-positive, unipolar flagellated, and rod-shaped bacterium capable of hydrolyzing casein, gelatin and collagens. Phylogenetic analysis revealed that strain SM1988T formed a distinct phylogenetic lineage along with known genera within the family Pseudoalteromonadaceae, with 16S rRNA gene sequence similarity being less than 93.3% to all known species in the family. Based on the phylogenetic, genomic, chemotaxonomic and phenotypic data, strain SM1988T was considered to represent a novel species in a novel genus in the family Pseudoalteromonadaceae, for which the name Flocculibacter collagenilyticus gen. nov., sp. nov. is proposed, with the type strain being SM1988T (= MCCC 1K04279T = KCTC 72761T). Strain SM1988T showed a high production (236 U/mL) of extracellular collagenases, which had high activity against both bovine collagen and codfish collagen. Biochemical tests combined with genomic and secretomic analyses indicated that the collagenases secreted by strain SM1988T are serine proteases from the S8 family. These data suggest that strain SM1988T acts as an important player in marine collagen degradation and recycling and may have a promising potential in collagen resource utilization.
