Legionella micdadei pneumonia diagnosed by culture isolation and DNA-DNA hybridization from bronchial lavage fluid

Abstract

An 80-year-old man was admitted because of dyspnea on effort. We suspected an acute exacerbation of chronic heart failure and idiopathic interstitial pneumonia caused by right-sided pneumonia. A nodular shadow in right upper lobe spread and consolidated into the airspace, and it failed to improve despite administration of meropenem trihydrate, vancomycin hydrochloride and clindamycin. A definitive diagnosis of Legionella micdadei pneumonia was made on the basis of this organism being isolated in culture from bronchial lavage fluid and subsequent identification of Legionella micdadei using DNA-DNA hybridization. The airspace consolidation gradually improved following treatment with intravenous erythromycin and minocycline hydrochloride.