Impact of biofilm formation on mortality in Candida tropicalis candidaemia: A retrospective study of ICU and Non-ICU patients.

PURPOSE: To investigate the clinical factors associated with biofilm formation in Candida tropicalis bloodstream infections and to evaluate its impact on patient mortality in a high-prevalence setting in Thailand.

MATERIALS AND

METHODS

We retrospectively analysed 146 episodes (from 145 patients) of C. tropicalis candidaemia at a Thai referral centre (2015-2019). Biofilm formation was quantified by XTT assay and classified as low, moderate, or high. Clinical predictors of high biofilm formation (HBF) and associations with 30-day mortality were evaluated using regression and Kaplan-Meier analyses.

RESULTS

Forty-nine isolates (33.6%) were HBF. Independent risk factors for HBF included shorter hospital stay prior to candidaemia (OR 0.98; 95% CI 0.96-0.999; P = 0.037) and recent Clostridioides difficile infection (OR 14.55; 95% CI 1.58-133.75; P = 0.018). Overall 30-day mortality was 74.0% and did not differ between HBF and non-HBF isolates (77.6% vs. 72.2%; P = 0.484). However, in non-ICU episodes, HBF was associated with significantly lower survival, whereas outcomes in ICU episodes were similar regardless of biofilm capacity.

CONCLUSIONS

Biofilm formation in C. tropicalis candidaemia was linked to recent C. difficile infection and earlier onset of bloodstream infection, and predicted poorer survival in non-ICU episodes.