Nocardiosis: A case series and literature review

Nocardiosis is caused by a branched Gram-positive bacillus that affects mostly immunosuppressed patients. The clinical manifestations can be localized or disseminated, and the treatment depends on the affected organs, the severity of the disease, and the susceptibility profile. Nocardiosis should be considered in the differential diagnosis of localized or disseminated abscesses in immunosuppressed patients. Early clinical suspicion would allow the start of empirical treatment, prompt microbiological research, and may positively impact survival. We present a case series of 14 patients with infection by Nocardia spp. who attended different health institutions in Bogotá between January 2008 and November 2023. The clinical microbiology laboratory provided information on demographic, clinical, and laboratory variables. Fourteen patients were analyzed, with an average age of 49.8 years (30 to 72 years); 10 were men, and nine had a diagnosis involving immunosuppression: six had cancer and three had other underlying immunosuppression. Diabetes and hypertension were the most common comorbidities. The infection was chronic in 10 patients; the organs involved were the brain and lungs in 7 cases. Nocardia species’ was identified in five subjects; one of the patients presented infection with Cryptococcus spp. Nocardiosis treatment was prolonged and included trimethoprim-sulfamethoxazole in 12 cases; four patients died. Infection by Nocardia spp. is primarily opportunistic, presents unique clinical and microbiological aspects, and is a differential diagnosis of localized or systemic abscesses in immunosuppressed patients. Clinical suspicion allows a careful approach in terms of diagnosis, and initiation of empiric antibiotic treatment can positively impact survival.