Streptococcus pneumoniae

Question 1

Morphology

Answer 1

capsulated gram positive diplococci

Question 2

Virulence

Answer 2

Streptomycin O- binds to cholesterol in the membranes of eukaryotic cells and oligomerizes to form large transmembrane pores

Pneumolysin - cytotoxic to alveolar and pulmonary epithelium

PAMP- triggers host response (cytokines)

IgA protease- specifically cleave human immunoglobulin A1 (IgA1)

Lipoteichoic Acid (LTA) - Activates Immune Cells via Toll-like Receptor, Lipopolysaccharide-binding Protein (LBP), and CD14

Polysaccharide capsule- antiphagocytic

Question 3

1 Virulence

Answer 3

Streptolysin O (SLO): binds to cholesterol in the membranes of eukaryotic cells and oligomerizes to form large transmembrane pores

Question 4

Strep pneumoniae infects who?

Answer 4

B cell deficient patients/Ig A deficient patients/ splenectomy (don’t have a spleen)/ sickle cell disease patients/ middle ear infections/ basilar skull fracture(CSF rhinorrehea)

Question 5

Lab diagnosis

Answer 5

alpha hemolytic (green appearance on blood agar), Gram stain demonstrating purple lancet shaped diplocci and neutrophils, optochin sensitive, bile soluble, quellung reaction (E-test/capsule swelling with specific antibodies)

Question 6

Treatment for patients under 2 years of age

Answer 6

13 valent conjugate vaccine

Conjugate- Similar to subunit vaccines- conjugate vaccines use only portions of the germ. Many bacteria molecules are coated by a sugar called polysaccharide. This coating hides or disguises the germ (antigens) so that the immature immune systems of infants are not able to recognize it. a subunit vaccine which combines a weak antigen with a strong antigen as a carrier so that the immune system has a stronger response to the weak antigen

Question 7

Treatment for patients 2yr +

Answer 7

PPV 23 valent pure polysaccharide

Question 8

What kind of pneumonia does it cause?

Answer 8

Acute bacterial community acquired pneumonia (#1 cause)