A neonate develops neonatal meningitis on day 3. CSF culture grows a beta-haemolytic Gram-positive coccus in chains. The CAMP test is positive and hippurate hydrolysis is positive. Which serogroup is most pathogenic in neonates and what is the first-line treatment?

• A Group A Streptococcus; IV benzyl penicillin alone
• B Group B Streptococcus (GBS), serogroup III; IV ampicillin + gentamicin ✓
• C Streptococcus pneumoniae; IV ceftriaxone
• D Enterococcus faecalis; IV vancomycin

Explanation

Streptococcus agalactiae (Group B Streptococcus, GBS) is the leading cause of neonatal early-onset meningitis, with serogroup III being most virulent and neuroinvasive. CAMP test (enhanced haemolysis in presence of S. aureus) and hippurate hydrolysis are both positive for GBS, distinguishing it from other beta-haemolytic streptococci. First-line treatment is IV ampicillin combined with gentamicin (synergistic bactericidal effect) for 14–21 days. Intrapartum prophylaxis with penicillin given to GBS-positive mothers reduces early-onset neonatal GBS disease.

Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.