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Multiple functional domains of Enterococcus faecalis aggregation substance Asc10 contribute to endocarditis virulence.
Chuang, Olivia N; Schlievert, Patrick M; Wells, Carol L; Manias, Dawn A; Tripp, Timothy J; Dunny, Gary M.
Afiliação
  • Chuang ON; Department of Microbiology, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN 55455, USA.
Infect Immun ; 77(1): 539-48, 2009 Jan.
Article em En | MEDLINE | ID: mdl-18955479
ABSTRACT
Aggregation substance proteins encoded by sex pheromone plasmids increase the virulence of Enterococcus faecalis in experimental pathogenesis models, including infectious endocarditis models. These large surface proteins may contain multiple functional domains involved in various interactions with other bacterial cells and with the mammalian host. Aggregation substance Asc10, encoded by plasmid pCF10, is induced during growth in the mammalian bloodstream, and pCF10 carriage gives E. faecalis a significant selective advantage in this environment. We employed a rabbit model to investigate the role of various functional domains of Asc10 in endocarditis. The data suggested that the bacterial load of the infected tissue was the best indicator of virulence. Isogenic strains carrying either no plasmid, wild-type pCF10, a pCF10 derivative with an in-frame deletion of the prgB gene encoding Asc10, or pCF10 derivatives expressing other alleles of prgB were examined in this model. Previously identified aggregation domains contributed to the virulence associated with the wild-type protein, and a strain expressing an Asc10 derivative in which glycine residues in two RGD motifs were changed to alanine residues showed the greatest reduction in virulence. Remarkably, this strain and the strain carrying the pCF10 derivative with the in-frame deletion of prgB were both significantly less virulent than an isogenic plasmid-free strain. The data demonstrate that multiple functional domains are important in Asc10-mediated interactions with the host during the course of experimental endocarditis and that in the absence of a functional prgB gene, pCF10 carriage is actually disadvantageous in vivo.
Assuntos

Texto completo: 1 Bases de dados: MEDLINE Assunto principal: Proteínas de Bactérias / Enterococcus faecalis / Fatores de Virulência / Endocardite Bacteriana / Proteínas de Membrana Tipo de estudo: Prognostic_studies Limite: Animals Idioma: En Revista: Infect Immun Ano de publicação: 2009 Tipo de documento: Article País de afiliação: Estados Unidos

Texto completo: 1 Bases de dados: MEDLINE Assunto principal: Proteínas de Bactérias / Enterococcus faecalis / Fatores de Virulência / Endocardite Bacteriana / Proteínas de Membrana Tipo de estudo: Prognostic_studies Limite: Animals Idioma: En Revista: Infect Immun Ano de publicação: 2009 Tipo de documento: Article País de afiliação: Estados Unidos