• Analysis of Shigella flexneri Resistance, Biofilm Formation, and Transcritpional Profile in Response to Bile Salts

      Nickerson, Kourtney P.; Chanin, Rachael B.; Sistrunk, Jeticia R.; Rasko, David A.; Fink, Peter J.; Barry, Eileen M.; Nataro, James P.; Faherty, Christina S. (2017-06)
    • Bioactive Immune Components of Anti-Diarrheagenic Enterotoxigenic E. coli (ETEC) Hyperimmune Bovine Colostrum Products

      Sears, Khandra T.; Tennant, Sharon M.; Reymann, Mardi K.; Simon, Raphael; Konstantopoulos, Nicky; Blackwelder, William C.; Barry, Eileen M.; Pasetti, Marcela F. (2017-06-21)
    • The Critical Role Of Zinc in a New Murine Model of Enterotoxigenic E. coli (ETEC) Diarrhea

      Bolick, David T.; Medeiros, Pedro Henrique Quintela Soares; Ledwaba, S. E.; Lima, Aldo A. M.; Nataro, James P.; Barry, Eileen M.; Guerrant, Richard L. (2018)
      Enterotoxigenic E. coli are major causes of traveler's diarrhea as well as endemic diarrhea and stunting in children in developing areas. However a small mammal model has been badly needed to better understand and assess mechanisms, vaccines and interventions. We report a murine model of ETEC diarrhea, weight loss and enteropathy, and investigate the role of zinc on the outcomes. LT=ST producing enterotoxigenic E. coli (ETEC) given to weaned C57BL/6 mice after antibiotic disruption of normal microbiota cause growth impairment, watery diarrhea, heavy stool shedding and mild to moderate intestinal inflammation, the latter worse with zinc deficiency. Zinc treatment promoted growth in zinc deficient infected mice, and subinhibitory zinc reduced expression of ETEC virulence genes cfa1, cexE, sta2 and degP, but not eltA in vitro. Zinc supplementation increased shedding and ileal burden of WT ETEC but decreased shedding and tissue burden of LTKO ETEC. LTKO ETEC infected mice had delayed disease onset and also had less inflammation by fecal MPO assessment. These findings provide a new murine model of ETEC infection that can help elucidate mechanisms of growth, diarrhea and inflammatory responses as well as potential vaccines and interventions.
    • Deletion of the MFS transporter fptB alters host cell interactions and attenuates the virulence of Type A Francisella tularensis

      Balzano, Phillip Mario Jan; Cunningham, Aimee L.; Grassel, Christen; Barry, Eileen M. (Washington DC: The American Society for Microbiology, 2018-01)
      Francisella tularensis is a Gram negative facultative intracellular coccobacillus that can infect a wide variety of hosts. In humans, F. tularensis causes the zoonosis tularemia following insect bites, ingestion, inhalation, and the handling of infected animals. That a very small inoculum delivered by the aerosol route can cause severe disease, coupled with the possibility of its use as an aerosolized bioweapon, have led to the classification of Francisella tularensis as a Category A select agent and has renewed interest in the formulation of a vaccine. To this end, we engineered a Type A strain SchuS4 derivative containing a targeted deletion of major facilitator superfamily (MFS) transporter fptB. Based on the attenuating capacity of this deletion in the F. tularensis LVS background, we hypothesized that deletion of this transporter would alter intracellular replication and cytokine induction of the Type A strain and attenuate virulence in the stringent C57BL/6J mouse model. Here we demonstrate that deletion of fptB significantly alters the intracellular lifecycle of F. tularensis, attenuating intracellular replication in both cell line and primary macrophages, and inducing a novel cytosolic escape delay. Additionally, we observed prominent differences in the in vitro cytokine profile in human macrophage-like cells. The mutant was highly attenuated in the C57BL/6J mouse model, and provided partial protection against virulent Type A F. tularensis challenge. These results indicate a fundamental necessity for this nutrient transporter in the timely progression of F. tularensis through its replication cycle, and in pathogenesis.