Dr. Tang-Siegel and her laboratory are interested at understanding pathogenesis of orally originated microorganisms and, bacteriophage manipulation of human microbiome. The Gram-negative, capnophilic, facultative anaerobe, Aggregatibacter actinomycetemcomitans is a causative agent of periodontitis, mostly notable for its association with aggressive forms of the disease and its resilient survival in two important serum-rich habitats, i.e., inflammatory periodontal pockets and blood circulations, due to its naturally developed resistance to complement-mediated phagocytosis. A. actinomycetemcomitans can be found from the oral cavity of approximately 20% of the population and potentially causes systemic infections, e.g., infective endocarditis, as well as morbidities, including autoimmune diseases and neurodegenerative disorders driven by stimulation and release of proinflammatory cytokines. Importantly, this microorganism has been identified with acquired antibiotic resistance mechanisms, including mobile rRNA methylase genes and the multidrug efflux pump system. The rising antimicrobial resistance and the emergent resistance mechanisms, including from human oral microbiome, as well as the unique in vivo resilience and the highly genomic diversity of this microorganism with seven known serotypes lead to the investigation of bacteriophages and A actinomycetemcomitans. The increased application of using phages as alternative anti-microbial agents requires understanding phage infection and replication in vivo. A. actinomycetemcomitans can be developed as a platform to provide insights into phage behaviors in a mimic, in vivo physiological condition.