Shorter vs. standard-duration antibiotic therapy for nocardiosis: a multi-center retrospective cohort study

Purpose The prolonged treatment recommended for nocardiosis does not rely on strong evidence. Consequently, some clinicians opt shorter therapy in certain circumstances. We assessed the effectiveness of shorter therapy. Methods A multi-center retrospective cohort study comprising individuals diagnosed with nocardiosis between 2007 and 2022. We classified all patients who survived 90 days into three groups according to treatment duration: short (<= 90 days), intermediate (91-180 days), and prolonged (> 180 days). We compared baseline characteristics (comorbidities, immune status) and nocardiosis manifestations across the unadjusted treatment groups, one-year all-cause mortality, disease relapse, and antibiotic-related adverse events to identify patients who may safely receive the short course. Results We detected 176 patients with nocardiosis, their median age was 65 years; 74 (42%) were women. Forty-three (24%) patients died within 90 days. Of the remaining 133, 37 (28%) patients received short therapy, 40 (30%) intermediate, and 56 (42%) prolonged treatment duration. Longer courses were more likely to be administered to patients with immunosuppression, disseminated nocardiosis, and N. farcinica infection. Within a year, 20 (15%) individuals died and 2 (2%) relapsed. Treatment duration was not associated with either mortality (p = 0.945) or relapse (p = 0.509). Nocardiosis was the cause of death in only one patient, receiving a prolonged course. Of 73 patients with solitary pulmonary nocardiosis, 20 (27%) received short duration. None relapsed and 2 (10%) died, both immunocompromised. The rate of AE was similar across the groups. Conclusions With clinically guided case-by-case patient selection nocardiosis can be safely treated for durations significantly shorter than traditionally recommended.