Lung Nocardia elegans infection diagnosed on matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS).

A 73-year-old man with adultonset Still's disease developed a high fever, coughing, dyspnea and bloody sputum and was therefore admitted to our hospital. Thoracic X-ray and CT scans revealed oval lesions in the bilateral lungs. A bacterial isolate from the sputum was identified to be Nocardia elegans (N. elegans) on comparative 16S rRNA gene sequencing and Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS). The patient recovered following treatment with imipenem/cilastatin and amikacin. To the best of our knowledge, this is the first case of nocardiosis caused by N. elegans identified on MALDI-TOF MS.