PresentationA 66-year-old male presents to the hospital with 3 weeks of dizziness, headaches and gait instability in the setting of a cerebellar brain mass. A computerized tomography (CT) scan was performed and compared to previous scans. The mass was now 3.7 cm, rapidly enlarging and required diagnostic biopsy to rule out infection and other etiologies.
Lab TestingOn admission a suboccipital craniotomy was performed in order to biopsy the mass. A yellow purulent material was retrieved and sent to the microbiology laboratory for routine bacterial (aerobic and anaerobic), fungal and acid-fast culture. In addition to culture, the laboratory performed Gram stain, Acid Fast stain and Modified Acid-Fast (Kinyoun) stain directly on the sample to aid in the diagnosis. Gram stain was positive for weakly gram-positive bacilli that were beaded in appearance. The Kinyoun stain was also positive for organisms resembling Nocardia spp. Growth on routine media and a Nocardia Quad Plate was consistent with Nocardia spp. 16S sequencing was performed off of bacterial growth which resulted in an identification of Nocardia farcinica.
Cause of SymptomsNocardia are aerobic, branching, Gram-positive, weakly acid-fast bacteria. They are ubiquitous in the water, organic matter and in the soil. The most common species associated with skin infections are Nocardia asteroides. N. farcinica is part of the Nocardia asteroides complex. N. farcinica are clinically relevant species and have been associated with brain abscesses. Infections are more often seen in the immunocompromised host. Infections can be serious with disseminated infection occurring rather frequently. The patient also had a mass in the lung which was previously thought to be cancer but was diagnosed as N. farcinica based on the brain biopsy results.
TreatmentTreatment consisted of intravenous Imipenem and Bactrim for 6 weeks. The patient was discharged on a course of oral antibiotics as an outpatient for an additional year.
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