A 3-week-old neonate has subtle swelling of the left thigh and pseudoparalysis of the limb with minimal fever. Imaging shows metaphyseal lesions in both femora and the proximal humerus. Blood culture grows gram-positive diplococci in chains. Which organism is the most likely cause?

• A Staphylococcus aureus
• B Haemophilus influenzae type b
• C Escherichia coli
• D Group B Streptococcus ✓

Explanation

Neonatal haematogenous osteomyelitis differs from childhood disease: it is often multifocal, involves the hip and other joints readily because metaphyseal vessels still penetrate the physis, and systemic signs are muted. Group B Streptococcus is the classic neonatal pathogen and appears as gram-positive cocci in chains. Staphylococcus aureus remains the commonest cause beyond the neonatal period but does not form chains.

Reference: Tachdjian's Pediatric Orthopaedics, 5th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.