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Query: UMLS:C0032285 (pneumonia)
 54,520 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Group B streptococci (GBS) are the leading cause of neonatal pneumonia and meningitis. Adherence of GBS to host tissues may play an important role in the pathogenesis of infection. The host molecules which mediate GBS adherence to host tissues are unknown. Many bacterial pathogens adhere to fibronectin, an important component of the extracellular matrix (ECM). Some pathogens adhere to both immobilized and soluble fibronectin, while others adhere to immobilized fibronectin, but not to soluble fibronectin. Previous data indicated that GBS do not adhere to soluble fibronectin. We studied the ability of GBS to adhere to immobilized fibronectin. Forty-five per cent of the input inoculum of COH1, a virulent GBS isolate, adhered to fibronectin immobilized on polystyrene. COH1 did not adhere to the other ECM proteins tested (laminin, type I collagen, vitronectin, and tenascin). Nine out of nine GBS strains from human sources tested adhered specifically to fibronectin at levels varying from 4-60%. We considered the possibility that GBS were adherent to a contaminant in the fibronectin preparation. Properties of fibronectin, including the presence of an immunologic epitope of fibronectin and binding to collagen, were verified to be properties of the molecule to which GBS adhere. COH1 adhered to fibronectin captured by a monoclonal antibody to fibronectin (FN-15), confirming that the molecule to which GBS adhere bears immunologic determinants of fibronectin. Adherence of COH1 to fibronectin was inhibited by collagen, confirming that the molecule to which GBS adhere binds to collagen. These data strongly suggest that GBS adhere to fibronectin, and not to a contaminant.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Group B streptococci adhere to a variant of fibronectin attached to a solid phase. 778 28

Group B Streptococcus (GBS) is a leading cause of neonatal sepsis, pneumonia and meningitis, and is responsible for a rising number of severe invasive infections in adults. For all disease manifestations, colonisation is a critical first step. GBS has frequently been isolated from the oropharynx of neonates and adults. However, little is understood about the mechanisms of GBS colonisation at this site. In this study it is shown that three GBS strains (COH1, NEM316, 515) have capacity to adhere to human salivary pellicle. Heterologous expression of GBS pilus island (PI) genes in Lactococcus lactis to form surface-expressed pili demonstrated that GBS PI-2a and PI-1 pili bound glycoprotein-340 (gp340), a component of salivary pellicle. By contrast, PI-2b pili did not interact with gp340. The variation was attributable to differences in capacities for backbone and ancillary protein subunits of each pilus to bind gp340. Furthermore, while GBS strains were aggregated by fluid-phase gp340, this mechanism was not mediated by pili, which displayed specificity for immobilised gp340. Thus pili may enable GBS to colonise the soft and hard tissues of the oropharynx, while evading an innate mucosal defence, with implications for risk of progression to severe diseases such as meningitis and sepsis.
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PMID:Group B Streptococcus pili mediate adherence to salivary glycoproteins. 2557 26