UNRAVELING THE MOLECULAR MECHANISMS OF BACILLUS PARAMYCOIDES PATHOGENESIS.A STUDY ON TOXINS PRODUCTION HOST –PATHOGEN INTERACTION AND IMMUNOMODULATORY EFFECTS.

Background: Bacillus paramycoides is an emerging species within the Bacillus genus that has recently been associated with gastrointestinal and systemic infections. Unlike well-studied relatives such as B. cereus and B. anthracis, the pathogenic mechanisms of B. paramycoides remain largely undefined. Understanding its molecular pathways, virulence determinants, and immune evasion strategies is essential for improving clinical diagnostics and therapeutic interventions in light of rising antimicrobial resistance and foodborne disease incidence. Objective: To investigate the molecular basis of B. paramycoides pathogenicity by analyzing its toxin production, host-pathogen interactions, and immunomodulatory effects. Methods: Meat samples were collected aseptically from local retail sources in Abbottabad, Pakistan. Isolates were cultured on Mannitol Egg Yolk Polymyxin Agar and identified based on colony morphology, Gram staining, and biochemical profiling. Catalase, methyl red, motility, and coagulase tests were performed. Genomic and proteomic analyses were conducted to detect virulence factors. 16S rRNA gene sequencing and BLASTn analysis were used for species confirmation. Antimicrobial susceptibility testing and phylogenetic tree construction using MEGA X software were also performed. Results: All isolates exhibited round, smooth, white-yellow colonies, were Gram-positive rods, catalase-positive, methyl red-positive, motility-positive, and coagulase-negative. The 16S rRNA sequence showed 97.16% similarity to B. paramycoides (Accession No. MT299700.1). Antibiotic resistance was observed in 60% of strains against tetracycline and 75% against erythromycin. Genomic findings revealed genes encoding cytotoxic enzymes, adhesins, and secondary metabolites that likely contribute to immune evasion and host cell damage. Conclusion: This study provides foundational molecular insights into B. paramycoides pathogenesis, highlighting its clinical relevance and identifying potential targets for diagnostic and therapeutic strategies.