Description

An 82-year-old Japanese woman with duodenum papilla cancer was admitted with a 3-day history of fever, chills and nausea. A contrast-enhanced CT scan showed ring-enhanced and multiloculated low-density area in her liver and suspected pyogenic liver abscess (figure 1).

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Figure 1

Constrast-enhanced CT scan showing findings suggestive of liver abscess.

Drainage of the liver abscess was performed and Gram's staining of the abscess revealed Gram-negative bacilli with capsule formation. Blood cultures and abscess cultures grew Klebsiella pneumoniae. Growing colonies from the liver abscess on blood agar were shiny, cream-coloured, and the string test was positive (>5 mm string; figure 2). The patient was treated with cefepime for 2 weeks and switched to oral amoxicillin/clavulanate for an additional 4 weeks. No evidence of relapse of the infection was noted at the 6-month follow-up.

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Figure 2

Demonstrating the string test.

Community-acquired K pneumoniae liver abscess sometimes causes metastatic region such as ocular or central nervous system, and hypermucoviscous phenotype of K pneumoniae is associated with hypervirulence. The presence of capsular serotype K1, and to a lesser extent K2, appears to play a role in the virulence of this organism,1 ,2 and it is easy and very useful to identify the hypervirulence type of K pneumoniae by a string test in the community hospital's laboratory.1