This project will examine the role of determinants encoded by highly transmissible plasmid pCF10 of Enterococcus faecalis, and how these genes mediate plasmid transfer and persistence of enterococci in the mammalian gastrointestinal tract. E. faecalis is a leading cause of hospital-acquired infections whose treatment is impeded by the inherent and acquired antibiotic resistance of the organism, and by its ability to transition between commensal and pathogenic lifestyles. It is well understood that antibiotic treatment or impairment of normal host defenses can result in overgrowth of enterococci in the intestine. However, we know very little about the inherent traits that allow the organism to establish in a healthy intestine, or how antibiotic-resistance plasmids like pCF10 might impact competitive fitness of their bacterial host in the GI tract independent of antibiotic resistance. We will study the interactions between pCF10-carrying donor strains and plasmid-free recipients in germ-free mice, and in humanized animals carrying a human-derived gut microbial community. We will use powerful new screens to identify genetic determinants of competitive fitness and plasmid transfer in the GI tract, and begin to study their functions and mechanisms of action. We will use high-resolution microscopic techniques to examine the behavior of the organisms in vivo, and the expression of genes of interest. The results of this research will include the following: 1) We will determine the inherent frequencies of pCF10 transfer in various regions of the GI tract in the absence of antibiotic selection. 2) We will identify genes on both the plasmid and chromosome that impact transfer and competitive fitness. 3) We will use mathematical modeling and laboratory studies of regulatory mechanisms to correlate the functions of genetic control circuits to the enterococcal behavior in the natural environment. 4) In the longer term, we may identify new ecologically based strategies, which could reduce enterococcal infections or the spread of antibiotic resistance.

Public Health Relevance

Enterococcus faecalis is a leading cause of hospital-acquired infections that resist antibiotic treatment. In this project we will study how plasmid DNAs carrying antibiotic-resistance genes transfer between enterococcal strains the gastrointestinal tract. The results of this research could lead to new approaches to prevent or control enterococcal infections and resistance transfer.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Unknown (R35)
Project #
1R35GM118079-01
Application #
9070922
Study Section
Special Emphasis Panel (ZGM1-TRN-7 (MR))
Program Officer
Reddy, Michael K
Project Start
2016-06-07
Project End
2021-05-31
Budget Start
2016-06-07
Budget End
2017-05-31
Support Year
1
Fiscal Year
2016
Total Cost
$411,030
Indirect Cost
$136,030
Name
University of Minnesota Twin Cities
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
555917996
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
Hirt, Helmut; Greenwood-Quaintance, Kerryl E; Karau, Melissa J et al. (2018) Enterococcus faecalis Sex Pheromone cCF10 Enhances Conjugative Plasmid Transfer In Vivo. MBio 9:
Breuer, Rebecca J; Hirt, Helmut; Dunny, Gary M (2018) Mechanistic Features of the Enterococcal pCF10 Sex Pheromone Response and the Biology of Enterococcus faecalis in Its Natural Habitat. J Bacteriol 200:
Breuer, Rebecca J; Bandyopadhyay, Arpan; O'Brien, Sofie A et al. (2017) Stochasticity in the enterococcal sex pheromone response revealed by quantitative analysis of transcription in single cells. PLoS Genet 13:e1006878
Bhatty, Minny; Camacho, Martha I; Gonzalez-Rivera, Christian et al. (2017) PrgU: a suppressor of sex pheromone toxicity in Enterococcus faecalis. Mol Microbiol 103:398-412
Chen, Yuqing; Bandyopadhyay, Arpan; Kozlowicz, Briana K et al. (2017) Mechanisms of peptide sex pheromone regulation of conjugation in Enterococcus faecalis. Microbiologyopen 6:
Weaver, Keith E; Chen, Yuqing; Miiller, Elly M et al. (2017) Examination of Enterococcus faecalis Toxin-Antitoxin System Toxin Fst Function Utilizing a Pheromone-Inducible Expression Vector with Tight Repression and Broad Dynamic Range. J Bacteriol 199:
Bandyopadhyay, Arpan; O'Brien, Sofie; Frank, Kristi L et al. (2016) Antagonistic Donor Density Effect Conserved in Multiple Enterococcal Conjugative Plasmids. Appl Environ Microbiol 82:4537-45
Dunny, Gary M; Berntsson, Ronnie Per-Arne (2016) Enterococcal Sex Pheromones: Evolutionary Pathways to Complex, Two-Signal Systems. J Bacteriol 198:1556-1562