A ten-year retrospective analysis of nocardiosis in a tertiary care center of South-coastal India

Abstract

Nocardiosis is an uncommon life-threatening infection caused by Nocardia spp. This study aimed to review the distribution of risk factors, clinical characteristics, microbiological findings, treatment and outcome of patients diagnosed with nocardiosis. This study was a retrospective case record review of all nocardiosis cases that were diagnosed at our tertiary care hospital from January 2008 to December 2019. A total of 48 patients with a mean age of 52.2±16.28 years were included. Out of which forty one (85%) were diagnosed as pulmonary nocardiosis and seven (14.6%) as disseminated disease. Chronic lung disease 25 (52.1%), long term steroid use 22 (45.8%) followed by diabetes mellitus 11 (22.9%) were common predisposing factors. The common symptoms were fever (87.5%), cough (79.2%) and breathlessness (52.1%). The most frequent radiologic finding included consolidation in 38 (79.1%), cavitation with thickened wall in 2 (4.1%), reticulonodular shadows in 2 (4.1%), and unilateral pleural effusion in 5 (10.4%). Nocardia otitidiscaviarum (22.9%) was frequently isolated from cultures. Resistance to trimethoprim-sulfamethoxazole (TMP-SMX) was observed in 21% cases. Mortality was noted in 6 (12.5%) patients and all were with pulmonary involvement. The percentage of death among those with and without pulmonary tuberculosis was 33.3% and 5% respectively. Patients affected by pulmonary nocardiosis with previous history of pulmonary tuberculosis showed significant association with poor outcome (p-value=0.05). In conclusion, nocardiosis mainly affects patients with structural lung disease or immunocompromised hosts with adverse outcome. Awareness of this infection is crucial for a clinician, and any suspicion should lead to make an early diagnosis and choose an appropriate empirical treatment to improve the outcome in this population.

Keywords: Nocardia spp.; immunocompromised; pulmonary nocardiosis.

Figure 1

Yearly percentage (%) of nocardiosis cases diagnosed in the tertiary care hospital between 2008 and 2019.

Figure 2

A. Chest radiograph of a patient on immunosuppressive therapy after renal transplantation infected with Nocardia spp. showing patchy consolidation in the right upper, middle and lower zones and in the left middle zone. B. Computed tomography of a patient with bronchial asthma on chronic steroid therapy revealing consolidation with areas of breakdown and air bronchograms in apicoposterior segment of left upper lobe with adjacent areas of ground glass opacification and nodules.

Figure 3

A. Kinyoun staining showing partial acid-fast filaments; B. Gram staining showing thin, Gram positive, branching filaments suggestive of nocardia.

Figure 4

Antibiotic resistance patterns.