The Role of Streptococcus pneumoniae in Community-Acquired Pneumonia

Abstract

<jats:title>Abstract</jats:title><jats:p>With the notable exceptions of the United States and Canada in particular, the global burden of disease in adults due to invasive infection with the dangerous respiratory, bacterial pathogen, Streptococcus pneumoniae (pneumococcus) remains. This situation prevails despite the major successes of inclusion of polysaccharide conjugate vaccines (PCVs) in many national childhood immunization programs and associated herd protection in adults, as well as the availability of effective antimicrobial agents. Accurate assessment of the geographic variations in the prevalence of invasive pneumococcal disease (IPD) has, however, been somewhat impeded by the limitations imposed on the acquisition of reliable epidemiological data due to reliance on often insensitive, laboratory-based, pathogen identification procedures. This, in turn, may result in underestimation of the true burden of IPD and represents a primary focus of this review. Other priority topics include the role of PCVs in the changing epidemiology of IPD in adults worldwide, smoking as a risk factor not only in respect of increasing susceptibility for development of IPD, but also in promoting pneumococcal antibiotic resistance. The theme of pneumococcal antibiotic resistance has been expanded to include mechanisms of resistance to commonly used classes of antibiotics, specifically β-lactams, macrolides and fluoroquinolones, and, perhaps somewhat contentiously, the impact of resistance on treatment outcome. Finally, but no less importantly, the role of persistent antigenemia as a driver of a chronic, subclinical, systemic proinflammatory/procoagulant phenotype that may underpin the long-term sequelae and premature mortality of those adults who have recovered from an episode of IPD, is considered.</jats:p>

Pneumolysin induces platelet destruction, not platelet activation, which can be prevented by immunoglobulin preparations in vitro

“…Community-acquired pneumonia by primary or secondary infection with Streptococcus pneumoniae (S pneumoniae; the pneumococcus) is one of the most frequent severe infections associated with high mortality. 1,2 Patients are at risk of developing acute respiratory distress syndrome requiring mechanical ventilation. A hallmark of acute respiratory distress syndrome is extravasation of protein-rich fluid into the pulmonary tissue, for example, when the pore-forming toxin pneumolysin alters the alveolo-capillary barrier.…”

Streptococcus pneumoniae Binds to Host Lactate Dehydrogenase via PspA and PspC To Enhance Virulence

“… Streptococcus pneumoniae ( Spn ) is an opportunistic human pathogen capable of causing a wide spectrum of serious infectious diseases, including pneumonia, bacteremia, sepsis, and meningitis ( 1 ). The pneumococcus is the leading cause of community-acquired pneumonia and invasive disease worldwide ( 2 ). Spn is a Gram-positive bacterium with teichoic acid and lipoteichoic acid being major constituents of its cell wall and cell membrane, respectively ( 3 ).…”

Crystal Structure and Pathophysiological Role of the Pneumococcal Nucleoside-binding Protein PnrA

“…However, there are no homologs known in the Gram-positive human pathobiont Streptococcus pneumoniae (the pneumococcus). While pneumococci colonize, as part of the microbiota, the upper respiratory tract as harmless commensals, they can convert into harmful pathogens causing severe lung infections and invasive infections such as septicemia and meningitis [6][7][8]. Pneumococcal disease caused an estimated 826,000 deaths in children under 5 years of age worldwide, accounting for 11% of all deaths in children under 5 years [9].…”