Outcomes and treatment for disseminated nocardiosis caused by Nocardia otitidiscaviarum: a systematic review

Abstract Introduction Nocardiosis is a rare aerobic gram-positive cause of infection, often in immunocompromised individuals. Nocardiosis is usually a localized pulmonary disease, however, it can lead to disseminated disease. More than 40 species of Nocardia have been described to cause infections in humans, with many having variable susceptibility and resistance patterns to antimicrobials, such as Nocardia otitidiscaviarum . Because disseminated infection due to N. otitidiscaviarum is uncommon and has been reported to exhibit distinct and sometimes unpredictable antimicrobial susceptibility, we focused the review specifically on disseminated disease caused by this species. Methods A comprehensive and systematic search strategy was developed and included online databases from PubMed, Web of Science, and ScienceDirect to extract all relevant articles published until December 2023. This review has been conducted in line with the PRISMA guidelines. The protocol of this review is registered in the National Institute of Health Research Prospective Register of Systematic Reviews PROSPERO (CRD42024503651). Results A total of nine cases of disseminated Nocardia otitidiscaviarum were identified using our search strategy. Mean age of patients was 39 years, half of them had a pulmonary initial site of infection, and the other half had skin as an initial site of infection, with the brain being the most common dissemination site. Most patients were immunocompromised, except one case where disseminated infection was reported in an immunocompetent host. The most sensitive antimicrobial agent was amikacin, which was sensitive in all cases; followed by TMP-SMX, and linezolid. Conclusion Disseminated Nocardia otitidiscaviarum infections are difficult to treat, with poor outcomes, and scarce evidence guiding the best therapeutic approach; this review makes a step in the right direction of shedding some light on the possible therapeutic agents to be used, and their relevant susceptibility and resistance rates, it demonstrates that amikacin has to be included in any patient diagnosed with disseminated Nocardia otitidiscaviarum . Clinical trial Not applicable.