Enterococci are bacteria that grow naturally inside human intestines. Over the last few decades, these pathogens have developed resistance to our most potent antibiotics, including vancomycin, an antibiotic of last resort for infectious disease. Vancomycin-resistant Enterococcus (VRE) does not cause illness to healthy individuals. But it does cause severe illness to hospital patients, especially the ones who have undergone antibiotic therapy. Antibiotic therapy eliminates a lot of the good bacteria in the gut of humans. VRE grab and fill this vacuum, spreading quickly from the intestines to the bloodstream and from there to the spleen, the liver, the heart. There they grow and cause disease that can no longer be easily treated with antibiotics. We genetically engineer lactic acid bacteria (LAB) to specifically target enterococcus inside gastrointestinal (GI) tracts. We propose to administer these cellbots to mice and examine if enterococcus vanishes from mouse GI tracts. We pursue three specific aims: First we engineer smart LAB that can detect enterococci. Upon detection, engineered LAB produce and release proteins. In the second aim, we engineer these proteins to be lethal to enterococci. In the third aim, we will examine the efficacy of our modified LAB in mice. We will infect mice with enterococcus and then administer LAB to them. The main hypothesis is that engineered LAB kill enterococci and stop their colonization inside animal GI tracts. If successful, these experiments can lead to the development of a promising therapeutic strategy against enterococcal infections.

Public Health Relevance

Enterococcus is causing serious illness, especially to hospitalized patients, because it has become resistant to antibiotics. In this project we engineer lactic acid bacteria that sense enterococcus and then kill it. Lactic acid bacteria are safe to consume, go unscathed through the stomach environment and reside in the gastrointestinal tract. That is where they are engineered to produce and release anti-enterococcus proteins, reducing pathogenic counts and decreasing the probability of illness.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Study Section
Drug Discovery and Mechanisms of Antimicrobial Resistance Study Section (DDR)
Program Officer
Gerratana, Barbara
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University of Minnesota Twin Cities
Engineering (All Types)
Schools of Engineering
United States
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Geldart, Kathryn; Kaznessis, Yiannis N (2017) Characterization of Class IIa Bacteriocin Resistance in Enterococcus faecium. Antimicrob Agents Chemother 61:
Forkus, Brittany; Ritter, Seth; Vlysidis, Michail et al. (2017) Antimicrobial Probiotics Reduce Salmonella enterica in Turkey Gastrointestinal Tracts. Sci Rep 7:40695
Ekblad, Bie; Kyriakou, Panagiota K; OppegÄrd, Camilla et al. (2016) Structure-Function Analysis of the Two-Peptide Bacteriocin Plantaricin EF. Biochemistry 55:5106-16
McClintock, Maria K; Kaznessis, Yiannis N; Hackel, Benjamin J (2016) Enterocin A mutants identified by saturation mutagenesis enhance potency towards vancomycin-resistant Enterococci. Biotechnol Bioeng 113:414-23
Kyriakou, Panagiota K; Ekblad, Bie; Kristiansen, Per Eugen et al. (2016) Interactions of a class IIb bacteriocin with a model lipid bilayer, investigated through molecular dynamics simulations. Biochim Biophys Acta 1858:824-35
Geldart, Kathryn; Forkus, Brittany; McChesney, Evelyn et al. (2016) pMPES: A Modular Peptide Expression System for the Delivery of Antimicrobial Peptides to the Site of Gastrointestinal Infections Using Probiotics. Pharmaceuticals (Basel) 9:
Smadbeck, Patrick; Kaznessis, Yiannis N (2015) On a theory of stability for nonlinear stochastic chemical reaction networks. J Chem Phys 142:184101
Geldart, Kathryn; Borrero, Juan; Kaznessis, Yiannis N (2015) Chloride-Inducible Expression Vector for Delivery of Antimicrobial Peptides Targeting Antibiotic-Resistant Enterococcus faecium. Appl Environ Microbiol 81:3889-97
Smadbeck, Patrick; Kaznessis, Yiannis N (2015) Chemical master equation closure for computer-aided synthetic biology. Methods Mol Biol 1244:179-91
Borrero, Juan; Chen, Yuqing; Dunny, Gary M et al. (2015) Modified lactic acid bacteria detect and inhibit multiresistant enterococci. ACS Synth Biol 4:299-306

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