Neonatal meningitis caused by Escherichia coli is most commonly associated with which capsular (K) serotype?
- A K2
- B K1 ✓
- C K5
- D K12
Correct answer: B. K1
Explanation
E. coli K1 is responsible for approximately 80% of neonatal E. coli meningitis. The K1 capsular polysaccharide is chemically identical to the capsular polysaccharide of group A Neisseria meningitidis (both are sialic acid polymers), which may explain the lack of maternal transplacental antibody protection. K1 strains commonly carry the ibeA gene for brain endothelial invasion.
Reference: Jawetz, Melnick, and Adelberg's Medical Microbiology, 28th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.