A 48-year-old man with poorly controlled diabetes presents with fever, right upper quadrant pain, and a multiloculated liver abscess on CT. Aspirate grows a hypermucoviscous gram-negative rod that forms stringy strands when colonies are stretched with a loop. Which capsular serotype is most strongly associated with this syndrome?

• A Klebsiella pneumoniae serotype K1 ✓
• B Klebsiella oxytoca serotype O1
• C Klebsiella pneumoniae non-capsulated strain
• D Escherichia coli K1 capsule

Explanation

Hypervirulent K. pneumoniae, classically capsular serotype K1 and hypermucoviscous on string test, causes metastatic community-acquired liver abscess in diabetic and Asian patients. The string test reflects excess capsular polysaccharide production. E. coli K1 is a neonatal meningitis serotype and is not associated with hypermucoviscous liver abscess.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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