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. Introduction Pulmonary nocardiosis is an infrequent but severe infection that commonly presents as a subacute or chronic suppurative disease, mimicking a lung carcinoma, abscess or pulmonary tuberculosis (Gillespie, 2006). Nocardia spp. are aerobic, gram positive bacteria belonging to Actinomycetes and are responsible for localized or disseminated infection in animals or humans (Winn et al., 2006). In humans, N. asteroides complex is the predominant pathogen (Gillespie, 2006; Winn et al., 2006). Pulmonary infection is usually caused by N.asteroides (85%), where as N.brasiliensis causes cutaneous and subcutaneous abscess (Beaman and Beaman, 1994; Gillespie, 2006). Nocardia most often enters through the respiratory tract and produce infection in both immunocompromised and immunocompetent hosts. These organisms are found worldwide in soil, decaying vegetable matter and water, although they have the propensity to become airborne, particularly in dust particles (Gillespie, 2006). Inhalation of the organism is considered the most common route of entry. Case report A 24-year-old female was brought to the casualty with complaints of breathlessness, abdominal pain and vomiting for six days. She had productive cough with purulent sputum mixed with blood for 12 days. She was apparently normal two weeks back. There was no evidence of immunocompromised status. On admission, she was conscious, oriented, febrile and tachypneic. Her pulse rate was 126/min, temperature 39.1°C (102.4°F), respiratory rate 32/min, and blood pressure 110/80 mmHg. Chest auscultation revealed bilateral crepitations. Her hemoglobin was 8.6 g/dL and the leukocyte count 16,000 cells/ cu mm with 2% bands, 74% neutrophils and 24% lymphocytes. Microbiological examination of the sputum failed to identify a pathogen. A chest radiograph revealed bilateral irregular nodules (cavitating) with indistinct areas of haziness, prominent broncho-vascular markings and mild effusion (Figure 1). Abdominal examination was normal. Based on clinical, laboratory and radiological investigations a provisional diagnosis of community-acquired pneumonia was made and the patient was put on meropenem. Despite broad-spectrum antimicrobial therapy, her condition deteriorated. A pleural tap was done. Cytological smears of the pleural effusion demonstrated numerous neutrophils and reactive mesothelial cells. Microbiological examination of the drained fluid revealed Gram positive filamentous and branching bacilli, which was weakly acid fast by modified Ziehl Neelsen staining, suggestive of Nocardia spp (Figure 2). Computed tomography of the chest revealed thickening of the pleura with effusion in the right thorax. A pleural biopsy was done which showed a granulomatous tissue (Figure 3). She improved after sulfamethoxazo
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