Legionella indianapolisensis sp. nov., isolated from a patient with pulmonary abscess

To date, at least 50 species of Legionella have been described. These organisms are ubiquitous in nature and have been isolated from diverse ecological environments, including man-made structures such as cooling towers and spas. Legionellae have also been isolated from human and veterinary clinical specimens, and their roles in disease are well-established. This report describes the isolation of a novel Legionella species from a respiratory specimen from a patient with influenza and suspected pulmonary embolus.

A 68-year-old male presented to an Indianapolis-area hospital with pulmonary disease; upon workup, he was found to have influenza A. Bronchoalveolar lavage fluid was also submitted for conventional bacterial culture and Legionella culture. The patient was prescribed a broad-spectrum antibiotic and recovered.

A Legionella-like bacterium was isolated on buffered charcoal yeast extract agar, and mass spectrometry and comparative 16S rRNA gene sequencing inconclusively identified the isolate as a Legionella sp. Further analysis of the 16S rRNA gene confirmed the strain to be a new species, related to Legionella hackeliae. Physiochemical and morphological testing were used to confirm the discovery of a novel species, Legionella indianapolisensis sp. nov., type strain SMNF-IS.