Infectious Diseases and Microbiology - Pneumococcal Pneumonia (Streptococcus pneumoniae)

Infectious Diseases and Microbiology - Pneumococcal Pneumonia (Streptococcus pneumoniae) 
Gram-positive, lancet-shaped, optochin-sensitive, alpha-hemolytic diplococci with over 80 serotypes based on polysaccharide capsules are Streptococcus pneumoniae.

Aspiration of organisms populating the oropharynx, respiratory droplets, and direct touch are the three ways that infection is spread.
Susceptibility to infection is increased by chronic lung illnesses and viral respiratory infections. Meningitis can develop after head trauma, pneumonia, bacteremia, and sinus and ear infections.

Pneumococcal pneumonia is typified by a sudden onset of fever, shivering chills, and productive cough. It is typically lobar or diffuse bronchopneumonia. Blood is commonly found in sputum. Bacteremia is widespread.
S pneumoniae is a prevalent cause of meningitis, otitis media, and sinusitis.

Pneumolysin (which inhibits phagocytic killing), phosphorylcholine (which enables invasion), an antiphagocytic polysaccharide capsule, secretory IgA protease, and cell-wall components like peptidoglycan and teichoic acid—which elicit the host inflammatory response—are examples of virulence factors.

Colonies are sensitive to optochin, bile, and alpha hemolysis. diplococci in sputum that are lancet-shaped and gram-positive.
Identification Latex agglutination in cerebrospinal fluid. Type-specific identification is accomplished using the Quellung reaction.

Medication of choice is penicillin. The penicillin-resistant strains have responded well to vancomycin, erythromycin, and chloramphenicol. For babies, a conjugated vaccine against seven serotypes is available, in addition to a polyvalent vaccine for 23 serotypes.