Streptococcus pneumoniae: involvement of neuraminidase, autolysin and superoxide dismutase in respiratory tract infections
Year: 2010
Type: dissertation
Abstract: This study focuses on the Streptococcus pneumoniae virulence factors\nneuraminidases A and B, autolysin and superoxide dismutase, with the aim of\nimproved understanding of their roles in the pneumococcal infections.\nUnderstanding the pathogenesis of pneumococcal infection is important because\nthis bacterium is one of the most common bacterial causes of human disease and\ndeath and because of the emergence of multidrug-resistant strains and issues with\nthe current vaccines.\nUsing a murine model of bronchopneumonia it was shown that NanA and\nNanB have involvement in colonisation of the upper respiratory tract and in\nsystemic spread. Lack of either of these proteins enhanced bacterial clearance in\nthe nasopharynx, lungs and blood. Furthermore, this study demonstrated distinct\nroles for each of the neuraminidases, but also suggests synergistic action.\nInfection data clearly show that the absence of one neuraminidase is not\ncompensated by the presence of the other. This study identified, for the first time,\na role for NanB in pathogenesis and in multiplication at mucosal sites.\nThe major S. pneumoniae autolysin LytA has been implicated in\npathogenicity by releasing virulence factors and components of the cell wall. In this\nstudy, the avirulence of a pneumococcal autolysin-deficient mutant was confirmed.\nMoreover, the results show that early after infection, LytA is crucial to\npneumococcal survival and growth, both in the upper and lower respiratory tract.\nThe major pneumococcal enzyme for detoxifying superoxide is MnSOD,\nencoded by sodA. This study showed that absence of sodA impaired survival in\nthe respiratory tract, particularly early after infection, but its absence was not\nlethal, suggesting that other mechanisms are involved in superoxide detoxification.
Author: Sonia Manco
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W317697672