A sputum sample from a patient with Klebsiella pneumoniae pneumonia is tested with a string test: a loop stretched from a colony on agar produces a viscous string greater than 5 mm. This hypermucoviscous phenotype is associated with which clinical syndrome?

• A Hospital-acquired ventilator-associated pneumonia
• B Community-acquired necrotizing pneumonia with metastatic abscesses (liver, eye) ✓
• C Catheter-associated urinary tract infection
• D Primary bacteremia without identifiable source

Explanation

The string test detects hypermucoviscous Klebsiella pneumoniae strains, particularly serotypes K1 and K2, which cause the hypervirulent community-acquired syndrome. These strains cause necrotizing pneumonia in healthy individuals and metastatically spread to liver (abscess), eye (endophthalmitis), and CNS. Hospital-acquired VAP and catheter-associated UTI are typically caused by classic non-hypermucoviscous strains.

Reference: Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 9th ed.

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