A landscape of epidemiology and strain distribution of Nocardia in China.

Nocardiosis is an uncommon infection that can cause severe damage or be life-threatening. However, the epidemiology and strain distribution of nocardiosis in China remain poorly characterized. In this study, a comprehensive literature search was conducted using the keyword "('Nocardia' OR 'Nocardiosis') AND ('China' OR 'Chinese')" in PubMed and Web of Science, and "(Nuokajun) OR (Nukajun)" in the China National Knowledge Infrastructure (CNKI) database. All published cases of nocardiosis between April 1, 1990, and September 13, 2024, were included. Geographic analysis identified a concentration of cases in eastern coastal China. The mean patient age was 52.6 ± 17.4 years, with a male predominance (61.0%) and the highest burden in the 50-59 age group (24.4%). The primary infection sites were the lungs (69.9%), skin (30.3%), and brain/central nervous system (CNS) (19.3%). Disseminated infections accounted for 29.0% of all cases and were associated with a markedly higher mortality rate (16.1%) compared with the overall rate (9.0%), underscoring the importance of early diagnosis and treatment. The predominant species were Nocardia farcinica, Nocardia cyriacigeorgica, and Nocardia brasiliensis. Most isolates remained highly susceptible to trimethoprim-sulfamethoxazole, amikacin, and linezolid. This study has established a national epidemiological pattern of Nocardia infections and strain distribution in China. The elevated risk and mortality associated with disseminated infections warrant vigilance. This underscores the need for heightened clinical awareness of Nocardia infections and ensure timely screening and treatment.