Q - What is Neisseria meningitidis? A - It is a gram-negative, aerobic, diplococci bacteria → causes meningococcal infections.
Q - Morphology of Neisseria meningitidis: A -
- It is a gram-negative diplococci bacteria.
- It is a small (0.5-1.0μm in diameter), encapsulated, non-motile organism.
- Shows bipolar staining (diplococci with a central dot).
- Capsule is made up of polysaccharides and is responsible for virulence.
Q - Clinical Spectrum of Meningococcal Infections: A -
- Meningococcal meningitis (inflammation of meninges).
- Sepsis (blood infection).
- Meningococcemia (circulating bacteria in the blood).
- Waterhouse-Friderichsen syndrome (severe hemorrhagic syndrome).
Q - Life Cycle of Neisseria meningitidis: A -
- → Attachment to epithelial cells (nasopharyngeal mucosa) using pili.
- → Invasion of epithelial cells.
- → Colonization in nasopharyngeal mucosa.
- → Invasion of blood stream from nasopharyngeal mucosa.
- → Bacterial multiplication in blood stream.
- → Inflammation of meninges (meningitis).
- → Sepsis, meningococcemia, and Waterhouse-Friderichsen syndrome.
Memory trick: "Always Keep Neat Manners, Share, Sneeze, Mingle, Infect, Shed, Multiply, Invade, Cause Severe Hemorrhage."
Q - Laboratory Diagnosis of Neisseria meningitidis: A -
- Direct fluorescent antibody (DFA) test.
- Rapid latex agglutination test.
- Culture on selective media (e.g., Thayer-Martin agar).
- Gram stain to identify gram-negative diplococci.
- Capsular polysaccharide typing.
Q - Pathogenesis of Neisseria meningitidis: A -
- → Attachment to epithelial cells using pili.
- → Invasion of epithelial cells.
- → Colonization in nasopharyngeal mucosa.
- → Invasion of blood stream from nasopharyngeal mucosa.
- → Bacterial multiplication in blood stream.
- → Inflammation of meninges.
- → Sepsis, meningococcemia, and Waterhouse-Friderichsen syndrome.
Q - Types of Neisseria meningitidis: A -
- There are 12 serogroups (A, B, C, D, E, F, H, I, K, L, W, and X).
- Serogroups A, B, C, W, and Y are most common in humans.
Q - Complications of Meningococcal Infections: A -
- Meningitis.
- Sepsis.
- Meningococcemia.
- Waterhouse-Friderichsen syndrome.
- Hearing loss.
- Blindness.
- Septic arthritis.
- Osteomyelitis.
Q - Management of Meningococcal Infections: A -
- Supportive care (rest, fluids, etc.).
- Antimicrobial therapy (e.g., ceftriaxone).
- Vaccination (e.g., meningococcal conjugate vaccine).
- Prophylaxis (e.g., rifampin).