Pulmonary nocardiosis presenting as bilateral pneumonia in an immunocompetent patient – An unusual host response

Pulmonary nocardiosis (PN) is an infrequent and severe infection due to Nocardia spp., which may behave as both opportunistic and primary pathogens. The presentation of a Nocardia infection is quite variable. We report a case of pulmonary nocardiosis in an immunocompetent 24-year-old female, who was initially treated with meropenem without response. A chest radiograph revealed bilateral irregular nodules (cavitating) with indistinct areas of haziness, prominent broncho-vascular markings and mild effusion. Nocardia spp. was isolated from pleural fluid. Pleural biopsy showed a granulomatous lesion with branching filamentous bacilli. She improved after trimethoprim-sulfamethoxazole was added along with meropenem. Our report emphasizes that a high level of clinical suspicion is required in patients without risk factors. In a patient with pneumonia if the lung infection responds poorly to antimicrobial therapy for community acquired pneumonia, pulmonary nocardiosis should be considered and a careful search for evidence of the organism is necessary. Furthermore our case emphasizes that although pulmonary nocardiosis is usually suppurative in nature, rarely a granulomatous response may occur.