title: Bacteriocin production augments niche competition by enterococci in the mammalian gastrointestinal tract.
abstract: Enterococcus faecalis is both a common commensal of the human gastrointestinal tract and a leading cause of hospital-acquired infections. Systemic infections with multidrug-resistant enterococci occur subsequent to gastrointestinal colonization. Preventing colonization by multidrug-resistant E. faecalis could therefore be a valuable approach towards limiting infection. However, little is known about the mechanisms E. faecalis uses to colonize and compete for stable gastrointestinal niches. Pheromone-responsive conjugative plasmids encoding bacteriocins are common among enterococcal strains and could modulate niche competition among enterococci or between enterococci and the intestinal microbiota. We developed a model of colonization of the mouse gut with E. faecalis, without disrupting the microbiota, to evaluate the role of the conjugative plasmid pPD1 expressing bacteriocin 21 (ref. 4) in enterococcal colonization. Here we show that E. faecalis harbouring pPD1 replaces indigenous enterococci and outcompetes E. faecalis lacking pPD1. Furthermore, in the intestine, pPD1 is transferred to other E. faecalis strains by conjugation, enhancing their survival. Colonization with an E. faecalis strain carrying a conjugation-defective pPD1 mutant subsequently resulted in clearance of vancomycin-resistant enterococci, without plasmid transfer. Therefore, bacteriocin expression by commensal bacteria can influence niche competition in the gastrointestinal tract, and bacteriocins, delivered by commensals that occupy a precise intestinal bacterial niche, may be an effective therapeutic approach to specifically eliminate intestinal colonization by multidrug-resistant bacteria, without profound disruption of the indigenous microbiota.
authors.affiliation: Division of Gastroenterology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.|Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Sushma
authors.initials: S
authors.lastname: Kommineni
authors.affiliation: Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Bretl
authors.affiliation: Division of Gastroenterology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Vy
authors.initials: V
authors.lastname: Lam
authors.affiliation: Division of Gastroenterology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.|Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Rajrupa
authors.initials: R
authors.lastname: Chakraborty
authors.affiliation: Division of Gastroenterology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Hayward
authors.affiliation: Division of Quantitative Health Sciences, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Pippa
authors.initials: P
authors.lastname: Simpson
authors.affiliation: Division of Quantitative Health Sciences, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Yumei
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Division of Gastroenterology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Pavlos
authors.initials: P
authors.lastname: Bousounis
authors.affiliation: Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Kristich
authors.affiliation: Division of Gastroenterology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.|Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Nita H
authors.initials: NH
authors.lastname: Salzman
mesh_terms: D000818:Animals; D001430:Bacteriocins / Q000096:biosynthesis* / Q000235:genetics; D003227:Conjugation, Genetic / Q000235:genetics; D004195:Disease Models, Animal; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D013293:Enterococcus faecalis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D041981:Gastrointestinal Tract / Q000382:microbiology*; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology / Q000628:therapy; D008297:Male; D051379:Mice; D050296:Microbial Viability / Q000235:genetics; D064307:Microbiota / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D013559:Symbiosis; D020713:Vancomycin Resistance
chemical_list: D001430:Bacteriocins