What is the function of Pneumolysin?
Pneumolysin is a cholesterol-dependent cytolysin (CDC) toxin that forms lytic pores in host membranes and mediates pneumococcal disease pathogenesis by modulating inflammatory responses.
What are the virulence factors of Streptococcus pneumoniae?
Important pneumococcal virulence factors include: the capsule; the cell wall; choline-binding proteins; pneumococcal surface proteins A and C (PspA and PspC); the LPXTG-anchored neuraminidase proteins; hyaluronate lyase (Hyl); pneumococcal adhesion and virulence A (PavA); enolase (Eno); pneumolysin; autolysin A (LytA); …
How does Streptococcus pneumoniae evade the immune system?
In order to evade the anti-bacterial effects of complement, pneumococci have developed many virulence factors that impair complement activity, thus contributing to bacterial evasion from the immune system (Jarva et al., 2003).
What virulence factor in Streptococcus pneumoniae makes the disease more severe in the host?
1. Polysaccharide capsule: S. pneumoniae’s extracellular polysaccharide capsule, the most important virulence factor (55), helps to initiate infection by allowing the bacterium to adhere to host cells and cause inflammation, while also providing protection from the host’s immune system (54, 55).
Is Pneumolysin an endotoxin?
A major exotoxin of Streptococcus pneumoniae is pneumolysin (24). Pneumolysin is a multifunctional bacterial cytoplasmic protein of 53 kDa with a wide range of cytotoxic and proinflammatory properties, and it is an important determinant of pneumococcal virulence (28).
How does pneumococcus cause disease?
Pneumococcal disease is caused by bacteria called Streptococcus pneumoniae (pneumococcus). People with pneumococcal disease can spread the bacteria to others when they cough or sneeze. Symptoms of pneumococcal infection depend on the part of the body affected.
What is the difference between R and S strains of Streptococcus pneumoniae?
The bacteriologists were interested in the difference between two strains of Streptococci that Frederick Griffith had identified in 1923: one, the S (smooth) strain, has a polysaccharide coat and produces smooth, shiny colonies on a lab plate; the other, the R (rough) strain, lacks the coat and produces colonies that …
Is Streptococcus AA pathogenic or nonpathogenic?
The genus Streptococcus is comprised of a wide variety of both pathogenic and non-pathogenic (commensal) gram-positive bacteria which are found to inhabit a wide range of hosts, including humans, horses, pigs and cows.
What is unique about Streptococcus pneumoniae?
Streptococcus pneumoniae are lancet-shaped, gram-positive, facultative anaerobic bacteria with more than 100 known serotypes. Most S. pneumoniae serotypes can cause disease, but only a minority of serotypes produce the majority of pneumococcal infections.
Why is Streptococcus pneumoniae capable of causing pneumonia?
Streptococcus pneumoniae, which initially inhabits the mucosal surfaces of the nasopharynx in its hosts (17), can migrate to the lungs, where it causes pneumococcal pneumonia (17).