title: Adherence and intracellular survival within human macrophages of Enterococcus faecalis isolates from coastal marine sediment.
abstract: Enterococcus faecalis is part of the human intestinal microbiota and an important nosocomial pathogen. It can be found in the marine environment, where it is also employed as a fecal indicator. To assess the pathogenic potential of marine E. faecalis, four strains isolated from marine sediment were analyzed for their ability to survive in human macrophages. Escherichia coli DH5α was used as a negative control. The number of adherent and intracellular bacteria was determined 2.5 h after the infection (T0) and after further 24h (T24) by CFU and qPCR counts. At T24 adherent and intracellular enterococcal CFU counts were increased for all strains, the increment in intracellular bacteria being particularly marked. No CFU of E. coli DH5α were detected. In contrast, qPCR counts of intracellular enterococcal and E. coli bacteria were similar at both time points. These findings suggest that whereas E. coli was killed within macrophages (no CFU, positive qPCR), the E. faecalis isolates not only escaped killing, but actually multiplied, as demonstrated by the increase in the viable cell population. These findings support earlier data by our group, further documenting that marine sediment can be a reservoir of pathogenic enterococci.
authors.affiliation: Department of Biomolecular Sciences, Section of Biochemistry and Molecular Biology, Università degli Studi "Carlo Bo", via A. Saffi 2, 61029, Urbino, Italy; Istituto Auxologico Italiano, Neurobiology Laboratory, Strada Cadorna 90, 28824, Piancavallo di Oggebbio, Italy. Electronic address: raffaella.sabatino@uniurb.it.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Sabatino
authors.affiliation: Department of Life and Environmental Sciences, Università Politecnica delle Marche, via Brecce Bianche, 60131, Ancona, Italy; Institute of Ecosystem Study (ISE), Microbial Ecology Group (MEG), Consiglio Nazionale delle ricerche (CNR), largo V. Tonolli 50, 28922, Verbania, Italy. Electronic address: andrix.di.cesare@alice.it.
authors.forename: Andrea
authors.initials: A
authors.lastname: Di Cesare
authors.affiliation: Department of Life and Environmental Sciences, Università Politecnica delle Marche, via Brecce Bianche, 60131, Ancona, Italy.
authors.forename: Sonia
authors.initials: S
authors.lastname: Pasquaroli
authors.affiliation: Department of Life and Environmental Sciences, Università Politecnica delle Marche, via Brecce Bianche, 60131, Ancona, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Vignaroli
authors.affiliation: Section of Toxicological, Hygienistic and Environmental Sciences, Università degli Studi "Carlo Bo", via A. Saffi 2, 61029, Urbino, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Citterio
authors.affiliation: Department of Life and Environmental Sciences, Università Politecnica delle Marche, via Brecce Bianche, 60131, Ancona, Italy.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Amiri
authors.affiliation: Department of Biomolecular Sciences, Section of Biochemistry and Molecular Biology, Università degli Studi "Carlo Bo", via A. Saffi 2, 61029, Urbino, Italy.
authors.forename: Luigia
authors.initials: L
authors.lastname: Rossi
authors.affiliation: Department of Biomolecular Sciences, Section of Biochemistry and Molecular Biology, Università degli Studi "Carlo Bo", via A. Saffi 2, 61029, Urbino, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Magnani
authors.affiliation: Istituto Auxologico Italiano, Neurobiology Laboratory, Strada Cadorna 90, 28824, Piancavallo di Oggebbio, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Mauro
authors.affiliation: Department of Life and Environmental Sciences, Università Politecnica delle Marche, via Brecce Bianche, 60131, Ancona, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Biavasco
mesh_terms: D001422:Bacterial Adhesion / Q000502:physiology*; D002478:Cells, Cultured; D015169:Colony Count, Microbial; D013293:Enterococcus faecalis / Q000502:physiology*; D019015:Geologic Sediments / Q000382:microbiology*; D006801:Humans; D008264:Macrophages / Q000382:microbiology*; D050296:Microbial Viability
keywords: Adhesion; Enterococcus faecalis; Internalization; Macrophages