The Role of Streptococcus pneumoniae in Community-Acquired Pneumonia

Abstract

Streptococcus pneumoniae (the pneumococcus) remains one of the most common causes of bacterial CAP, encompassing infections mild enough to be treated on an outpatient basis, as well as those requiring hospital care, or even intensive care unit admission. This microorganism is associated with a significant burden of disease, causing substantial morbidity and mortality worldwide, and generating considerable health-care costs. The reason that pneumococcal CAP remains such a common cause of disease relates to the presence of a number of risk factors for this infection in patients throughout the world. Such risk factors include extremes of age, lifestyle factors, including smoking and alcohol abuse, and various underlying co-morbid conditions, including congenital and acquired immunodeficiencies. This article will review various aspects of pneumococcal CAP, including the burden of pneumococcal disease, risk factors for pneumococcal infection, the occurrence of cardiovascular events in patients with pneumococcal CAP, the apparently pivotal role of pneumolysin, a major virulence factor of the pneumococcus, in the pathogenesis of severe infection and associated cardiac dysfunction, empiric antibiotic treatment for pneumococcal CAP, as well as adjunctive therapies, specifically those which target pneumolysin, and, finally, the mortality of such infections.

The burden of PCV13 serotypes in hospitalized pneumococcal pneumonia in Spain using a novel urinary antigen detection test. CAPA study

“…Pneumococcal disease in adults, including community-acquired pneumonia (CAP) and invasive pneumococcal disease (IPD), is a global health problem, mainly affecting individuals with chronic diseases such as COPD, diabetes mellitus and heart disease. The increased risk for pneumococcal pneumonia is present all year around [1] and the total disease burden comes mainly from noninvasive episodes, because IPD represents only a fraction [2].…”

Interleukin 17 Receptor E (IL-17RE) and IL-17C Mediate the Recruitment of Neutrophils during Acute Streptococcus pneumoniae Pneumonia

“…Streptococcus pneumoniae is a leading cause of community-acquired pneumonia (CAP) which frequently requires hospitalization and admission to an intensive care unit (19). Therefore, it is of interest to understand mechanisms that mediate tissue damaging inflammation during pneumococcal pneumonia.…”

Pneumolysin as a potential therapeutic target in severe pneumococcal disease

“…Notwithstanding disabling of complement-mediated protective immune mechanisms, it is the pore-forming cytolytic/pro-inflammatory activities of Ply which are the primary contributors to pneumococcal colonisation of the airways, invasion and extrapulmonary dissemination. 73 In addition, a very recent pre-clinical study has implicated the toxin, via its pro-inflammatory activities, in host-to-host transmission of the pneumococcus, due to inflammation-associated bacterial shedding in nasal secretions. 74 The involvement of Ply in the various stages of pneumococcal infection has recently been reviewed elsewhere 73 and is considered only briefly here.…”

“…73 In addition, a very recent pre-clinical study has implicated the toxin, via its pro-inflammatory activities, in host-to-host transmission of the pneumococcus, due to inflammation-associated bacterial shedding in nasal secretions. 74 The involvement of Ply in the various stages of pneumococcal infection has recently been reviewed elsewhere 73 and is considered only briefly here.…”