A 19-year-old college student presents with sudden onset high fever, petechial rash rapidly evolving to purpura fulminans and shock. CSF shows gram-negative diplococci intracellularly in neutrophils. Which serogroup of Neisseria meningitidis is responsible for most meningococcal disease in India and which vaccine is recommended?
- A Serogroup B is predominant; protein-based MenB vaccine recommended
- B Serogroup C is predominant; monovalent MenC conjugate vaccine recommended
- C Serogroup A is the predominant Indian strain; MenACWY quadrivalent conjugate vaccine recommended ✓
- D Serogroup Y is predominant; polysaccharide vaccine sufficient
Explanation
In India and sub-Saharan Africa, Neisseria meningitidis serogroup A is the most common cause of epidemic meningococcal meningitis. Serogroup A polysaccharide is capsular polymannosyl phosphate. The meningococcal conjugate quadrivalent vaccine (MenACWY) is recommended for high-risk groups, pilgrims (Haj) and as post-exposure prophylaxis contacts. Serogroup B capsule (polysialic acid) is poorly immunogenic as a polysaccharide alone (mimics host neural cell adhesion molecule); hence, protein-based MenB vaccines (Bexsero/Trumenba) are used in Europe/Americas where serogroup B predominates. Purpura fulminans results from DIC triggered by meningococcal endotoxin (LOS) and cytokine storm.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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