Characteristics of nocardiosis patients with different immune status from a Chinese tertiary general hospital during 8-year period

Background: Nocardia is an opportunistic pathogen from environment, which is generally thought to infect immunosuppressed patients (ISPs), but recent studies showed it could also cause infections in immunocompetent patients (ICPs). Objective: To compare the clinical characteristics, patients’ outcome, Nocardia species identification and antibiotic susceptibility profiles of nocardiosis between ICPs and ISPs. Methods: The detailed clinical data were collected from all the non-repetitive nocardiosis patients during 2011 and 2018, from a tertiary general hospital in Beijing, China. Then each Nocardia isolate was identified to species level by DNA sequencing. The antibiotic susceptibility testing was performed by E-test method, and interpreted following CLSI M24 document. The clinical and microbiological characteristics between ICPs and ISPs were compared statistically. Results: A total of 23 non-repetitive nocardiosis patients with detailed clinical data were enrolled in this study. Among them, 9 were ICPs and 14 were ISPs. All the skin and soft tissue infections occurred in ICPs (33.3% versus 0%, P<0.05). Bronchiectasis occurred more frequently in ICPs (44.4% versus 21.4%), while chronic kidney diseases and co-infection with aspergillosis occurred more frequently in ISPs (35.7% versus 0%, 35.7% versus 0%, respectively), although they did not reach the statistical significance. There were no significant difference in other clinical characteristics, Nocardia species identification, and antibiotic susceptibility between ISPs and ICPs (P>0.05). Conclusion: Nocardiosis could occur in both ISPs and ICPs. Skin and soft tissue infection and bronchiectasis occurred more frequently in ICPs. Chronic kidney diseases and co-infection with aspergillosis occurred more frequently in ISPs. These characteristics should be noticed by physicians in diagnosis of nocardiosis.