LAUSR

ABSTRACT Host lipid metabolism is an important target for subversion by pathogenic mycobacteria such as Mycobacterium tuberculosis. The appearance of foam cells within the granuloma are well‐characterised effects of chronic tuberculosis. The zebrafish‐Mycobacterium marinum infection model recapitulates many aspects of human‐M. tuberculosis infection and is used as a model to investigate the structural components of the mycobacterial granuloma. Here, we demonstrate that the zebrafish‐M. marinum granuloma contains foam cells and that the transdifferentiation of macrophages into foam cells is driven by the mycobacterial ESX1 pathogenicity locus. This report demonstrates conservation of an important aspect of mycobacterial infection across species. HIGHLIGHTSFoam cells are identified by Oil Red O staining in zebrafish adults and embryos infected with Mycobacterium marinum.The transdifferentiation of macrophages into foam cells is driven by the mycobacterial pathogenicity locus ESX1.Zebrafish are an emerging model for studying mycobacterial infection‐induced abnormalities in lipid metabolism.