title: Exogenous sialic acid transport contributes to group B streptococcus infection of mucosal surfaces.
abstract: By sequence analysis of available group B streptococcus (GBS) genomes, we discovered a conserved putative operon involved in the catabolism of sialic acid, containing a tripartite transporter formed by two integral membrane components and a sugar-binding unit, named SAL0039. Expression analysis in the presence of different substrates revealed that SAL0039 was specifically upregulated by the presence of sialic acid and downregulated when bacteria were grown in human blood or in the presence of a high concentration of glucose. The role of SAL0039 in sugar transport was supported by the inability of the sal0039 deletion mutant strain to import exogenous sialic acid and to grow in semidefined medium supplemented with this sugar. Furthermore, in vivo evidence showed that the presence of exogenous sialic acid significantly increased the capacity of GBS to infect mice at the mucosal level. These findings suggest that transport of sialic acid may also contribute to GBS infections.
authors: Novartis Vaccines and Diagnostics Srl, Siena,  Italy.
authors: Alfredo
authors: A
authors: Pezzicoli
authors: Paolo
authors: P
authors: Ruggiero
authors: Fulvia
authors: F
authors: Amerighi
authors: John L
authors: JL
authors: Telford
authors: Marco
authors: M
authors: Soriani
mesh_terms: D000818:Animals; D058491:Bacterial Load; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D005260:Female; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D016680:Genome, Bacterial; D005947:Glucose / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009092:Mucous Membrane / Q000382:microbiology; D019158:N-Acetylneuraminic Acid / Q000378:metabolism*; D009876:Operon; D012799:Sialyltransferases / Q000235:genetics / Q000378:metabolism; D013047:Specific Pathogen-Free Organisms; D013290:Streptococcal Infections / Q000382:microbiology*; D013292:Streptococcus agalactiae / Q000302:isolation & purification*
chemical_list: D001426:Bacterial Proteins; C098871:Neu5Ac N-acetylgalactosamine 2,6-sialyltransferase; D012799:Sialyltransferases; D019158:N-Acetylneuraminic Acid; D005947:Glucose