過粘稠性Klebsiella pneumoniae subsp. ozaenae による肺膿瘍の1例

抄録

Klebsiella pneumoniae subsp. ozaenae (K. ozaenae) has been reported to cause urinary tract infections and rhinosclerosis, but it has rarely been reported as a cause of lung abscess. Therefore, the clinical course and optimal antimicrobial treatment for lung abscess caused by K. ozaenae remain unclear. It has also been reported that infections caused by hyperviscous Klebsiella species are more likely to become invasive. We report a case of lung abscess caused by hyperviscous K. ozaenae. A 68-year-old woman presented with fever and right shoulder pain, and was referred to our hospital as a suspected case of pneumonia. Chest CT showed an abscess in the right S3, and we started the patient on intravenous ceftriaxone (CTRX) treatment. However, as the fever persisted and the patient became delirious, the antimicrobial agent was changed to meropenem (MEPM), based on the findings of sputum smear examination. K. ozaenae was isolated on sputum culture, with a positive string test. Although this bacterial strain is considered to be susceptible to CTRX and MEPM, the patientʼs fever and delirium failed to improve. The symptoms eventually improved with the addition of levofloxacin (LVFX). The patient was discharged without any sequelae on day 48 of hospitalization.