A 52-year-old female patient was admitted to our hospital. The patient presented with ongoing (3 days) ataxia in the right lower limbs, in addition to dizziness and a progressive headache. No fever was noted in the past month before admission. Her medical history was unremarkable; she was immunocompetent, her diabetes was well controlled, and she did not have a history of surgery or steroid abuse. Her social history included intermittent alcohol consumption without smoking. She was alert and responsive on admission. Physical examination revealed clear lung sounds without rales or wheezing. Her heartbeat was regular without any murmurs. There was no tenderness or rebound tenderness in the abdomen. Neurological examination revealed right-sided ataxia and dysarthria. There were no other symptoms, for example, fever, neck stiffness, photophobia, papilledema, or other abnormalities. Laboratory testing revealed a C-reactive protein level of 0.7 mg/dL and a white blood cell count of 8500 muL. The patient had a normal neutrophil function test result, lymphocyte count, and normal immunoglobulin levels. She was tested negative for human immunodeficiency virus (HIV), HIV antibodies, hepatitis B surface antigens, and hepatitis C antibodies. Cerebrospinal fluid revealed a white blood cell count of 18 cells/mm3, 70% lymphocytes (normal: <5% lymphocytes, no neutrophils, no monocytes), a red blood cell count of 1 cells/mm3, and protein level of 92.9 mg/dL (reference range: <45 mg/dL). Cultures were negative for bacterial and fungal infection. A computed tomography (CT) scan of the head showed a right cerebellar low-density lesion without hydrocephalus. A CT scan of the chest, abdomen, and pelvis did not show any abnormalities. Cerebral MRI disclosed multiple necrotic cystic ring-enhancing lesions in the right cerebellar juxtaventricular region with surrounding edema. Diffusion-weighted imaging (DWI) showed restricted diffusion [Figure 1]. With the diagnosis of a suspected primary brain tumor, the patient underwent craniotomy and partial resection of the mass. A soft, brown, purulent mass was observed, and resected without opening the forth ventricle using a microdissector, under high magnification. The preliminary histopathological study of the resected lesion indicated a brain abscess. A microbiological investigation of the diagnosis was made using the Gram and Grocott stains of the surgical specimens [Figure 2]. A gram-stained smear of the fluid showed branching, filamentous gram-positive bacilli, which were identified following culture as N. paucivorans, by means of 16S rRNA sequence analysis.
This preliminary in vitro resistance to TMP/SMX informed the choice of ceftriaxone sodium as initial empiric treatment. A subsequent susceptibility E-test confirmed that the pathogen was actually susceptible to TMP/SMX (minimum inhibitory concentration: 0.01 mug/mL); therefore, antimicrobial therapy was modified accordingly. Medical treatment included ceftriaxone sodium (2 g/12 h) for 1 month and TMP-SMX [1600 mg/320 mg intravenous (IV), daily] for 1 month, followed by transition to oral therapy levofloxacin (500 mg daily) and TMP-SMX (1600 mg/320 mg also oral daily) for an additional 11 months. The patient's clinical condition improved over the following 5 weeks, and she was discharged on Day 35 with no neurological deficit. After 1 year of treatment, MRI revealed no brain abscesses [Figure 3].