Two unusual cases of successful treatment of hypermucoviscous Klebsiella pneumoniae invasive syndrome

Abstract

Background: A few Japanese cases of hypermucoviscous Klebsiella pneumoniae (K. pneumoniae) invasive syndrome have recently been reported. Although extrahepatic complications from bacteremic dissemination have been observed, infected aneurysms are rare. Furthermore, the primary source of infection is generally a liver abscess, and is rarely the prostate. Therefore, we report two atypical cases of hypermucoviscous K. pneumoniae invasive syndrome.

Case presentation: The first case was an 81-year-old Japanese man with no significant medical history, who was referred to our hospital for vision loss in his right eye. Contrast-enhanced whole-body computed tomography revealed abscesses in the liver and the prostate, and an infected left internal iliac artery aneurysm. Contrast-enhanced head magnetic resonance imaging revealed brain abscesses. Cultures of the liver abscess specimen and aqueous humor revealed K. pneumoniae with the hypermucoviscosity phenotype, which carried the magA gene (mucoviscosity-associated gene A) and the rmpA gene (regulator of mucoid phenotype A). We performed enucleation of the right eyeball, percutaneous transhepatic drainage, coil embolization of the aneurysm, and administered a 6-week course of antibiotic treatment. The second case was a 69-year-old Japanese man with diabetes mellitus, who was referred to our hospital with fever, pollakiuria, and pain on urination. Contrast-enhanced whole-body computed tomography revealed lung and prostate abscesses, but no liver abscesses. Contrast-enhanced head magnetic resonance imaging revealed brain abscesses. The sputum, urine, prostate abscess specimen, and aqueous humor cultures revealed K. pneumoniae with the hypermucoviscosity phenotype, which carried magA and rmpA. We performed enucleation of the left eyeball, percutaneous drainage of the prostate abscess, and administered a 5-week course of antibiotic treatment.

Conclusions: Hypermucoviscous K. pneumoniae can cause infected aneurysms, and the prostate can be the primary site of infection. We suggest that a diagnosis of hvKP invasive syndrome should be considered in all patients who present with K. pneumoniae infection and multiple organ abscesses.

Keywords: Abscess; Endophthalmitis; Hypermucoviscous Klebsiella pneumoniae; Infected aneurysm; Prostate; String test; magA; rmpA.

Fig. 1

Findings from the first case. a Findings of remarkable edema and opacity in the cornea. b Contrast-enhanced whole-body computed tomography (CT) reveals a liver abscess (white arrow). c Contrast-enhanced whole-body CT reveals prostate abscesses (white arrows). d Contrast-enhanced head magnetic resonance imaging reveals a brain abscess (white arrow). e The first case provided colonies on the agar plate that stretched for >5 mm using the inoculation loop (white arrows), which indicates a positive string test result. f Contrast-enhanced whole-body CT reveals the enlargement of an existing left internal iliac artery aneurysm (white arrow)

Fig. 2

Findings from the second case. a Findings of remarkable edema and opacity in the cornea. b Contrast-enhanced whole-body computed tomography (CT) reveals lung abscesses (white arrows). c Contrast-enhanced whole-body CT reveals prostate abscesses (white arrows). d Contrast-enhanced head magnetic resonance imaging reveals a brain abscess (white arrow). e The second case provided colonies on the agar plate that stretched for >5 mm using the inoculation loop (white arrows), which indicates a positive string test result

Fig. 3

Agarose gel electrophoresis. Lane 1: 1–10 kbp DNA ladder; Lane 2: 100–1,500 bp DNA ladder; Lanes 3 and 4: the PCR product reveals magA and rmpA in the first patient; Lanes 5 and 6: the PCR product reveals magA and rmpA in the second patient