A neonate born at 36 weeks presents on day 2 with temperature instability, bulging fontanelle, and cerebrospinal fluid showing pleocytosis with gram-positive cocci in chains. Which organism is most likely and what is the drug of choice?
- A Listeria monocytogenes — Ampicillin
- B Group B Streptococcus — Penicillin G ✓
- C Enterococcus faecalis — Vancomycin
- D Staphylococcus epidermidis — Vancomycin
Correct answer: B. Group B Streptococcus — Penicillin G
Explanation
Group B Streptococcus (GBS, Streptococcus agalactiae) is a gram-positive coccus arranged in chains and remains the leading cause of early-onset neonatal meningitis (presenting within 3–7 days). Penicillin G is the drug of choice; ampicillin is used if GBS is suspected but not yet confirmed. Listeria monocytogenes is a gram-positive rod (not coccus in chains). Coagulase-negative staphylococci are the leading cause of late-onset sepsis, not meningitis with gram-positive cocci in chains.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.