Question

What is the most common cause of community acquired pneumonia and major cause of otitis media and meningitis in adults?

1) Influenza virus
2) Streptococcus pneumoniae
3) Haemophilus influenzae
4) Mycoplasma pneumoniae

Answer 1

The most common cause of community-acquired pneumonia and a major cause of otitis media and meningitis in adults is Streptococcus pneumoniae, a bacteria that interferes with immune response and causes significant inflammation and tissue damage.

Step-by-step explanation:

The most common cause of community-acquired pneumonia, as well as a major cause of otitis media and meningitis in adults, is Streptococcus pneumoniae. This gram-positive bacterium is often found as part of the respiratory tract's normal flora. It causes disease by colonizing the lungs and producing a polysaccharide capsule that interferes with phagocytic clearance.

Virulence factors like pneumolysin O contribute to tissue damage and a pronounced inflammatory response. In the case of otitis media, encapsulated strains of S. pneumoniae are especially prevalent in older infants and children. For meningitis, S. pneumoniae can traverse the blood-brain barrier, leading to inflammation of the meninges. These infections can be severe and require prompt antibiotic treatment.