To identity the pathogen of pulmonary nocardiosis complicated with brain abscess and to provide assistance for clinical diagnosis and therapy.

The clinical data, imaging examination, diagnosis and treatment were reviewed, respectively, and the identification of pathogenic bacteria, antimicrobial susceptibility testing and 16S rRNA sequence were determined.

The patient had a history of long-term administration of corticosteroids. Clinical manifestations were fever and cough. The results of laboratory showed that white blood cell, neutrophil cells and C-reactive protein (CRP) were all above normal range. The colonies were white, rough and surface folds after 2 days culture of sputum. Gram staining for the sputum samples and the isolate were beaded or branched Gram-positive bacilli.The weak acid fast staining test by 1% sulfuric acid and acid fast staining test were both negative. The isolate could not be identified by automatic bacteria identification instrument. Nocardia farcinica was identified by Matrix-Assisted Laser Desorption Ionization-time of Flight Mass Spectrometry (MODI-TOF MS) and 16S rRNA sequencing. Antimicrobial susceptibility detection by KB disks method showed that it were sensitive to amikacin, ciprofloxacin, imipenem, levofloxacin, linezolid and minocycline, but resistant to cotrimoxazole, ceftriaxone, ampicillin and erythromycin. Lung imaging showed that the double lung multiple patchy shadows, nodules, and later developed into the cavity. Brain CT showed multiple brain abscess. After application of sulfamethoxazole ceftriaxone combined with, the pulmonary cavity was absorbed and the patient’s condition were stable after surgical drainage and excision of abscess.

Molecular method for identification of Nocardia farcinica is rapid, accurate. Early pathogenic diagnosis was the key for treatment of nocardiosis. Combination treatment including sulfonamides, early, sufficient, full course of treatment should be executive.