title: Inactivation of the Autolysis-Related Genes lrgB and yycI in Staphylococcus aureus Increases Cell Lysis-Dependent eDNA Release and Enhances Biofilm Development In Vitro and In Vivo.
abstract: Staphylococcus aureus ica-independent biofilms are multifactorial in nature, and various bacterial proteins have been associated with biofilm development, including fibronectin-binding proteins A and B, protein A, surface protein SasG, proteases, and some autolysins. The role of extracellular DNA (eDNA) has also been demonstrated in some S. aureus biofilms. Here, we constructed a Tn551 library, and the screening identified two genes that affected biofilm formation, lrgB and yycI. The repressive effect of both genes on the development of biofilm was also confirmed in knockout strains constructed by allelic recombination. In contrast, the superexpression of either lrgB or yycI by a cadmium-inducible promoter led to a decrease in biofilm accumulation. Indeed, a significant increase in the cell-lysis dependent eDNA release was detected when lrgB or yycI were inactivated, explaining the enhanced biofilm formed by these mutants. In fact, lrgB and yycI genes belong to distinct operons that repress bacterial autolysis through very different mechanisms. LrgB is associated with the synthesis of phage holin/anti-holin analogues, while YycI participates in the activation/repression of the two-component system YycGF (WalKR). Our in vivo data suggest that autolysins activation lead to increased bacterial virulence in the foreign body animal model since a higher number of attached cells was recovered from the implanted catheters inoculated with lrgB or yycI knockout mutants.
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Departamento de Microbiologia Médica, Rio de Janeiro, RJ, Brazil.
authors.forename: Cristiana Ossaille
authors.initials: CO
authors.lastname: Beltrame
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Departamento de Microbiologia Médica, Rio de Janeiro, RJ, Brazil.
authors.forename: Marina Farrel
authors.initials: MF
authors.lastname: Côrtes
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Departamento de Microbiologia Médica, Rio de Janeiro, RJ, Brazil.
authors.forename: Raquel Regina
authors.initials: RR
authors.lastname: Bonelli
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Departamento de Microbiologia Médica, Rio de Janeiro, RJ, Brazil.
authors.forename: Ana Beatriz de Almeida
authors.initials: AB
authors.lastname: Côrrea
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Departamento de Microbiologia Médica, Rio de Janeiro, RJ, Brazil.
authors.forename: Ana Maria Nunes
authors.initials: AM
authors.lastname: Botelho
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Departamento de Microbiologia Médica, Rio de Janeiro, RJ, Brazil.
authors.forename: Marco Antônio
authors.initials: MA
authors.lastname: Américo
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Departamento de Microbiologia Médica, Rio de Janeiro, RJ, Brazil.
authors.forename: Sérgio Eduardo Longo
authors.initials: SE
authors.lastname: Fracalanzza
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Departamento de Microbiologia Médica, Rio de Janeiro, RJ, Brazil.
authors.forename: Agnes Marie Sá
authors.initials: AM
authors.lastname: Figueiredo
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D001433:Bacteriolysis; D018441:Biofilms / Q000254:growth & development*; D004269:DNA, Bacterial / Q000378:metabolism*; D004195:Disease Models, Animal; D015964:Gene Expression Regulation, Bacterial; D015723:Gene Library; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D016254:Mutagenesis, Insertional; D013203:Staphylococcal Infections / Q000235:genetics / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D037521:Virulence Factors