Recurring Klebsiella pneumoniae pyogenic liver abscesses in a resident of San Diego, California, due to a K1 strain carrying the virulence plasmid

Abstract

We report a diabetic patient who had three episodes of cryptogenic liver abscess due to Klebsiella pneumoniae. He was a Caucasian who lived in California and had no epidemiological connection to East Asia. The isolate from his third episode was a hyperviscous K1 strain that carried the Klebsiella virulence plasmid.

Fig. 1.

CT scans of the liver. (A) Noncontrast CT scan done on 30 January 2008 with a hypoattenuating lesion in hepatic segment IV measuring 4 cm. (B) Noncontrast CT scan done on 22 July 2008 with a hypoattenuating lesion bridging hepatic segments VII and VIII and measuring 7 cm. (C) Noncontrast CT scan done on 10 November 2010 with a hypoattenuating lesion in hepatic segment VIII measuring 3.3 cm.

Fig. 2.

Bacteria were boiled in a PCR master mixture containing the primers for the plasmid genes (12), and then Taq polymerase was added. The primers for magA amplification were added to a separate mixture (3). PCR products were run on a 1.5% agarose gel. Lanes A and B are the standard strain containing the virulence plasmid (K. pneumoniae CG43) from H.-L. Tang, and lanes C and D are the patient's isolate. Lanes A and C are the products of the multiplex PCR for the virulence plasmid genes; B and D show magA. The clinical isolate was positive for all of the genes tested, identifying it as a K1 isolate containing the virulence plasmid genes. K. pneumoniae CG43 was a K2 strain, so it did not contain magA. Lanes MW contained molecular weight markers.