Unmasking Primary Candidemia: Clinical Features and Implications for Management

Source identification in candidemia is crucial for management and prognosis; however, a substantial proportion of cases are classified as primary candidemia without an identifiable source.

To assess the clinical relevance of primary candidemia and its impact on 7-day and 30-day mortality: METHODS: Single-center retrospective study of adult patients with candidemia from 2011 to 2025 at a tertiary university hospital. Clinical, microbiological, and outcome data were collected, and candidemia sources were classified using predefined clinical and microbiological criteria. Multivariable logistic regression was used to identify factors associated with 7- and 30-day mortality and primary candidemia.

A total of 533 candidemia episodes were analysed; 33.2% were classified as primary candidemia. Overall, 7 and 30-day mortality were 16.5% and 32.1%. Septic shock (OR 3.6, 95% CI: 2.1-6.3; p < 0.001) and primary candidemia (OR 2.2, 95% CI: 1.2-3.8; p = 0.011) were independently associated with increased 7-day mortality. In the cases of primary candidemia, 50.8% of all deaths occurred within the first 5 days. This source was associated with male sex (OR 1.7, 95% CI: 1.1-2.5; p = 0.016) and N. glabratus infection (OR 2.1, 95% CI: 1.3-3.3; p = 0.001). 30-day mortality was influenced by host-related factors (liver disease, neutropenia, and haematopoietic stem cell transplantation).

Primary candidemia accounts for a substantial proportion of cases and is associated with high 7-day mortality. The predominance of C. albicans and N. glabratus, common gut colonisers, supports gastrointestinal translocation as a potential source. Delayed diagnosis, particularly of N. glabratus, highlights the need for appropriate empirical therapy and rapid diagnostic tools.