title: The Intraperitoneal Transcriptome of the Opportunistic Pathogen Enterococcus faecalis in Mice.
abstract: Enterococcus faecalis is a Gram-positive lactic acid intestinal opportunistic bacterium with virulence potential. For a better understanding of the adapation of this bacterium to the host conditions, we performed a transcriptome analysis of bacteria isolated from an infection site (mouse peritonitis) by RNA-sequencing. We identified a total of 211 genes with significantly higher transcript levels and 157 repressed genes. Our in vivo gene expression database reflects well the infection process since genes encoding important virulence factors like cytolysin, gelatinase or aggregation substance as well as stress response proteins, are significantly induced. Genes encoding metabolic activities are the second most abundant in vivo induced genes demonstrating that the bacteria are metabolically active and adapt to the special nutrient conditions of the host. α- and β- glucosides seem to be important substrates for E. faecalis inside the host. Compared to laboratory conditions, the flux through the upper part of glycolysis seems to be reduced and more carbon may enter the pentose phosphate pathway. This may reflect the need of the bacteria under infection conditions to produce more reducing power for biosynthesis. Another important substrate is certainly glycerol since both pathways of glycerol catabolism are strongly induced. Strongly in vivo induced genes should be important for the infection process. This assumption has been verified in a virulence test using well characterized mutants affected in glycerol metabolism. This showed indeed that mutants unable to metabolize this sugar alcohol are affected in organ colonisation in a mouse model.
authors.affiliation: U2RM-Stress and Virulence, University of Caen Basse-Normandie, EA4655, 14032 Caen, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Muller
authors.affiliation: U2RM-Stress and Virulence, University of Caen Basse-Normandie, EA4655, 14032 Caen, France; Institute of Microbiology, Catholic University of Sacred Heart, 00168, Rome, Italy.
authors.forename: Margherita
authors.initials: M
authors.lastname: Cacaci
authors.affiliation: U2RM-Stress and Virulence, University of Caen Basse-Normandie, EA4655, 14032 Caen, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sauvageot
authors.affiliation: Institute of Microbiology, Catholic University of Sacred Heart, 00168, Rome, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Sanguinetti
authors.affiliation: CUBE-Division for Computational Systems Biology, Dept. of Microbiology and Ecosystem Science, University of Vienna, 1090 Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Rattei
authors.affiliation: CUBE-Division for Computational Systems Biology, Dept. of Microbiology and Ecosystem Science, University of Vienna, 1090 Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Eder
authors.affiliation: U2RM-Stress and Virulence, University of Caen Basse-Normandie, EA4655, 14032 Caen, France.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Giard
authors.affiliation: Center for Biotechnology, Bielefeld University, 33594 Bielefeld, Germany.
authors.forename: Jörn
authors.initials: J
authors.lastname: Kalinowski
authors.affiliation: Institute of Medicine Microbiology, Gießen University, 35392 Gießen, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Hain
authors.affiliation: U2RM-Stress and Virulence, University of Caen Basse-Normandie, EA4655, 14032 Caen, France.
authors.forename: Axel
authors.initials: A
authors.lastname: Hartke
mesh_terms: D000818:Animals; D013293:Enterococcus faecalis / Q000235:genetics* / Q000472:pathogenicity; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D012329:RNA, Bacterial / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D059467:Transcriptome / Q000235:genetics*
chemical_list: D012329:RNA, Bacterial