Brain Abscess caused by Nocardia farcinica

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Background: Infections caused by Nocardia farcinica are potentially lethal because of the organism's tendency to disseminate and resist antibiotics. Nocardia brain abscess is rare and accounts for 1-2% of all cerebral abscesses. However, brain abscess is the most common secondary infection due to Nocardia species. Nocardia farcinica brain abscess has a high mortality rate, as high as 20% in immunocompetent patients and 55% in immunocompromised patients. Methods & Materials: A 60 yo male with a history of autoinmune hepatitis treated with prednisolone, presented to our clinic with aphasia and dysarthria which evolved into a fever episode,blood culture were negative. The results of the laboratory tests performed on admission were normal. A CTscan revealed a pleural base consolidation lesion in the left upper lobe with a small intralesional cavity, empiric traeatment with AMS was initiated. BAL cultures for bacteria, mycobacteria, fungi and nocardia were negative. Brain MRI was requested with diffusion: focal images with left parietal and cerebellar corticosubcortical morphology with perilesional edema and annular type reinforcement with gadolinium, the diagnosis was, therefore, brain abscess. Examination of theCSFshowed 5 WBCs/mm3, a glucose level of 40 mg/dL and a protein level of 147 mg/Dl. CSF cultures for bacteria, mycobacteria, fungi and nocardia were negative,microbiologic examination revealed grampositive branching bacilli and Modified ZN staining showed the presence of long, acid-fast branching filamentous bacilli. 3 days later, a partially acid-fast, branching gram-positive rod identified initially as Nocardia species was reported to be growing. Results: The isolate was identified as N. farcinica by MALDI-TOF at the NRL. Antibiotic susceptibility testing showed the sensitivity to TMP/SMX ([MIC] 0.125 mcg/mL), linezolid (1 mcg/mL), imipenem (1 mcg/mL), and intermediate to minocycline (2 mcg/mL), according to CLSI. M24-A2, 2011. Empiric treatment was stopped and he was started on TMP/SMX and Linezolid. Currently the patient is in stable neurological focus with clinical and ambulatory imaging controls. Conclusion: Cases of N. farcinica infections are being reported increasingly because of recent changes in taxonomy and diagnostic methodology. Because of the different antimicrobial sensitivity patterns among Nocardia species; both appropriate subtyping and susceptibility testing of uncommon species are required for the successful treatment of nocardial infections.