Our laboratory examines the relationship between Legionella pneumophila and environmental host amoebae. See our projects.
Our work encompasses the broad discipline of bacterial pathogenesis. We primarily focus on Gram-negative pathogens and the specialized secretion systems that promote virulence. One avenue of investigation involves recognition and transport of ‘effector’ proteins by the Dot/Icm type IVb secretion system in Legionella pneumophila. A second major area of emphasis examines the interplay between L. pneumophila and environmental host amoebae; a crucial and often underappreciated relationship. L. pneumophila cultured in amoebae convert to a transmissive form that is 10-100 times more infectious than a like-strain grown in artificial media; thus representing the pathogen in its most natural infectious state.
We developed an assay to quantitatively recover L. pneumophila from amoebae for use in target cell infections; a process we termed ‘protozoan priming’. Using this methodology, we examine the contribution of particular genetic loci to dissemination of Legionella from protozoa to macrophage. We have identified a catalog of virulence factors that are produced during the late stages of growth in amoebae specifically. Our long-term goal is to characterize factors that contribute to generation of bacteria augmented for virulence when cultivated inside a protozoan host.