Molecular mechanisms underlyinghost interactions.

Abstract

species are opportunistic pathogens that cause localized and disseminated infections, particularly in immunocompromised individuals. Despite their clinical importance, the molecular mechanisms underlyingpathogenicity remain incompletely understood. This review summarizes current advances invirulence factors, host immune responses, and intracellular survival strategies. A diverse array of virulence factors enablesto invade host cells, circumvent immune defenses, and maintain persistence within host tissues, including mammalian cell entry (Mce) proteins, antioxidant enzymes, phospholipase C, hemolysins, and siderophore-associated proteins. Host protection againstrelies primarily on innate immune responses, with neutrophils playing a central role and being coordinated by γδT cells and interleukin-17-mediated signaling pathways. In addition, the clinical epidemiology of nocardiosis and animal models ofinfection are also briefly summarized. However, most mechanistic studies remain restricted to a limited number of type strains. Further investigations into-host interactions are essential for the development of improved diagnostic, therapeutic, and preventive strategies for nocardiosis.