Epidemiology, risk factors and virulence analysis of Candida infection in Southwest China

Fungal infections, especially invasive candidiasis caused by Candida species, have been shown to increase mortality rates among critically ill patients. However, there remains a dearth of epidemiological data on invasive Candida infections in Southwest China. This retrospective study sought to address this gap by investigating species distribution, underlying diseases, and risk factors among hospitalized patients with confirmed Candida infections in hospitals of Southwest China from 2019-2023. Additionally, we systematically analyzed the virulence properties of strains isolated from different clinical sources and action of cytokines involved in inflammatory and immune responses. A total of 4662 patients were included in the present study, with 174 identified as having bloodstream infection. Our data revealed that Candida albicans was the predominant infecting organism. Univariate analysis showed significant differences in ICU admission, respiratory dysfunction, solid tumors, neurological disorders, and gastrointestinal pathology between patients with C. albicans infections and those with non-albicans Candida infections. Multivariate analysis demonstrated that non-albicans Candida species are common pathogens in central venous catheter associated bloodstream infections [OR (2.488; 95% CI, 1.043-5.934)]. The invasive virulence determinants of the clinical Candida strains were also determined in vitro and in vivo (Galleria mellonella and murine models). And cytokine profiles in mice with C. albicans infections varied by the source of the isolate. The prevalence of non-albicans Candida infections in Southwest China is progressively rising annually, exacerbated by underlying comorbidities in infected individuals. Thus, our work underscores the significance of prompt identification, diagnosis and management of Candida infections in clinical practice.