過粘稠性Klebsiella pneumoniaeによる頸部リンパ節膿瘍例

抄録

Klebsiella pneumoniae (K. pneumoniae), an oral and intestinal commensal bacterium, is a major cause of community-acquired infections, such as respiratory, urinary, and intra-abdominal infections. In recent years, invasive pathologies caused by hypervirulent K. pneumoniae, a variant that has increasingly been recognized as causing severe and life-threatening infections, including liver abscesses and systemic bloodstream dissemination/sepsis, have been reported.

A 22-year-old Southeast Asian woman was referred to our department with a left cervical swelling that she had noticed about 1 week earlier. Physical examination revealed a large swelling with overlying erythema in the left upper neck that was tender to palpation. Computed tomography (CT) showed a space-occupying lesion with an internal hypodense area in the left neck, suggestive of a cervical lymph node abscess.

Antibiotic therapy was initiated, percutaneous puncture drainage was performed, and K. pneumoniae colonies that tested positive for the string test were detected on pus culture. After three puncture drainages, followed by an incisional drainage, the abscess/neck swelling gradually improved. Hypervirulent K. pneumoniae produces excessive amounts of capsular substances and is associated with a hypermucoviscous phenotype that tests positive in the string test. In cases of a suspected hypervirulent, hypermucoviscous K. pneumoniae-induced abscess, early puncture or incisional drainage should be aggressively considered.