Bacterial Pathogenesis: Toxins, Secretion Systems, and Virulence Gene Regulation

This chapter provides a detailed mechanistic review of bacterial virulence determinants, with particular focus on protein secretion systems (Types I–VII), exotoxins, adhesins, and siderophores in clinically significant Gram-positive and Gram-negative pathogens. It critically evaluates the regulatory networks — including two-component systems, quorum sensing, and small regulatory RNAs — that govern virulence gene expression in response to host environmental cues. The chapter also reviews the translational significance of virulence factor characterisation for the identification of novel drug targets and the development of anti-virulence therapeutic strategies.