🩺 MEDLAB BOT AI • CLINICAL MLS MCQ
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📚 Specialty: Hematology & Clinical Microscopy (#HematologyampClinicalMicroscopy)
🎯 Difficulty: Intermediate
🔢 Item: #Q12

❓ QUESTION:
A lumbar puncture performed on a 3-day-old neonate presenting with lethargy and fever yields cloudy cerebrospinal fluid (CSF). Analysis reveals: WBC 3,200/µL (89% neutrophils), CSF glucose 14 mg/dL (concurrent blood glucose 78 mg/dL), and CSF protein 310 mg/dL. Gram stain reveals intra- and extracellular Gram-positive short rods/coccobacilli. Which organism is the most likely pathogen?

A) Listeria monocytogenes
B) Streptococcus agalactiae
C) Escherichia coli
D) Cryptococcus neoformans

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✅ CORRECT ANSWER: Option A

💡 CLINICAL RATIONALE & DIAGNOSTIC PEARLS:
Listeria monocytogenes is a major cause of neonatal bacterial meningitis that presents as tiny Gram-positive coccobacilli/short rods on Gram stain. Bacterial meningitis causes severe neutrophilic pleocytosis, elevated protein, and markedly decreased CSF-to-serum glucose ratios (<0.4). Streptococcus agalactiae is a Gram-positive coccus in chains, and E. coli is a Gram-negative rod.

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📢 MedLab Bot AI • Official Clinical Series