Nocardia bacteremia: A seven-year retrospective analysis of reported cases

Nocardia species can cause serious infections, especially in immunocompromised individuals, though it can also affect immunocompetent patients. Bacteremia due to this organism is always clinically significant and is associated with high mortality rates. We reviewed all cases of Nocardia bacteremia published in medical literature since 2019. A total of 28 studies providing data for 29 patients were included. Among all patients, 69% were male; the median age was 60 years. Overall, 23 (79.3%) patients were immunosuppressed [immunosuppressive treatment (73.9%), malignancies (34.8%), transplantation (26.1%), and autoimmune diseases (26.1%)]. Pulmonary involvement was the most frequent concomitant site of infection. Fever, cough, dyspnea, shortness of breath, and fatigue were the most commonly encountered symptoms. Seven patients (24.1%) had concurrent infections at the time of Nocardia bacteremia. Most isolates were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). N. farcinica was the most commonly identified species (44.8%), followed by N. cyricigeorgica (25%), and N. nova (10.3%). High rates of resistance were observed for amoxicillin/clavulanic acid and ciprofloxacin (57.1% for each), clindamycin (42.9%), cefotaxime (21.4%) and imipenem (21.4%). All 14 isolates tested for trimethoprim/sulfamethoxazole (TMP/SMX) and linezolid were susceptible. The median total duration of treatment was 7.2 months. TMP/SMX was used in 78.6% of patients, carbapenems in 60.7% and linezolid in 35.7%. Mortality rate was significant (34.5%). Nocardia bacteremia is a rare but serious disseminated form of nocardiosis. Early diagnosis and prompt aggressive treatment, typically with a combination of antibiotics and long-term therapy are crucial for improving outcomes.