Clostridium botulinum serotype B: microbial genetics, toxin biosynthesis, current applications, and future prospects.

Clostridium botulinum serotype B (Group I and II) is a Gram-positive, anaerobic bacterium renowned for producing botulinum neurotoxin type B (BoNT/B), a potent zinc-dependent endopeptidase. This mini-review explores the microbiological and genetic foundations of BoNT/B-producing strains, emphasizing their taxonomic classification, genomic plasticity, and toxin gene cluster organization (e.g., bont/B, ntnh, ha). The review highlights the bacterium’s environmental adaptability, driven by horizontal gene transfer and plasmid- or phage-encoded toxin genes, which influence strain diversity and toxin functionality. Structurally, BoNT/B exhibits unique receptor-binding specificity, targeting synaptotagmin I/II and gangliosides, a trait governed by evolutionary adaptations in its heavy-chain domain. Beyond its well-documented neuromuscular blockade, BoNT/B demonstrates emerging therapeutic applications in autonomic disorders and pain management, rooted in its selective cleavage of vesicle-associated membrane protein (VAMP). The review also discusses biotechnological innovations, such as engineered C. botulinum strains and nanotechnology-enhanced delivery systems, to optimize toxin yield and clinical efficacy. By integrating microbial genetics with translational insights, this work underscores C. botulinum serotype B as a model organism for studying toxin evolution and a promising platform for next-generation neurotherapeutics.