The genus Nocardia consists of a group of gram-positive environmental bacteria. They typically cause lung and brain infections in immunocompromised patients, even though one out of three infected patients have a normally functioning immune system. Being a ubiquitous microorganism, in some cases Nocardia has been associated with nosocomial acquired infections and surgical procedures. A review of the literature in this field follows the case report. A 47-year-old woman underwent an endoscopic third ventriculostomy and a left retro-sigmoid craniotomy for a schwannoma removal. Meningeal symptoms began a week later, in association with C reactive protein rise and leukocytosis. Cerebrospinal fluid (CSF) examination was clear with hypoglycorrhachia, hyperprotidorrachia and polymorphonuclear cells. Cultural exam was negative. At the brain magnetic resonance imaging (MRI) purulent material was described in the occipital ventricular horns. Empirical broad spectrum antibiotic therapy was given for 31 days until the brain MRI showed a resolution of the infection. Ten days later, the patient was admitted to the hospital because of new meningeal symptoms. Cerebrospinal fluid culture and Polymerase-chain reaction (PCR) Multiplex for the most important meningitis viruses and bacteria tested negative. A broad-spectrum antibiotic therapy was started with no benefit; thus, a broad-spectrum antifungal therapy was added with little success on clinical status. Meanwhile, a 16s and 18s rRNA PCR was executed on a previous Cerebrospinal fluid with negative results, excluding bacterial and fungal infections. For this reason, all the therapies were stopped. After a few days, high fever and meningeal signs reappeared. The brain MRI showed a meningoventriculitis. An Ommaya catheter with reservoir was inserted and the drawn CSF resulted in the growth of Nocardia farcinica. Antibiogram-based antibiotic therapy was started with intravenous imipenem and trimethoprim-sulfamethoxazole, showing clinical benefit. The patient was sent home with oral linezolid and amoxicillin/clavulanate for a total of 12 months of therapy. Nocardia rarely causes post-neurosurgical complication in a nosocomial setting. This case shows the difficulty in detecting Nocardia and the importance of the correct microbiological sample and antibiogram-based antibiotic therapy to achieve successful treatment.
Keywords: CNS infections; Hospital acquired infections; bacterial meningitis; bacterial ventriculitis; clinical microbiology; nocardiosis.