Temporal Trends of Candida Species in Healthcare-Associated Infections in Intensive Care Units in Taiwan

Background and Objectives: The epidemiological characteristics of Candida species have changed worldwide, with an increasing number of reports on co-infections with non-albicans Candida species (NACs) and multidrug-resistant bacteria. A longer length of hospital stay, more severely ill patients, and empirical antimicrobial use in intensive care units (ICUs) increased the prevalence of Candida healthcare-associated infections (HAIs). If the diagnosis or treatment of invasive candidiasis is delayed, the morbidity and mortality of patients will significantly increase. Materials and Methods: We conducted a nationwide surveillance study to analyze data on HAIs in the ICUs of medical centers and regional hospitals between 2018 and 2023. We assessed the temporal trends of Candida species (including Candida albicans and NACs) across all HAIs, bloodstream infections (BSIs), and urinary tract infections (UTIs), and simultaneously assessed the corresponding trends of Enterococcus faecium (Efm). A linear trend for the proportions of microorganisms from 2018 to 2023 was noted according to the Mantel-Haenszel chi-square test. Spearman's rank correlation coefficients were used to analyze the correlations between pathogen proportions, systemic antimicrobial agent consumption, and length of ICU stay. Results: The overall proportion of all Candida species in HAIs in the ICUs increased significantly from 15.13% to 16.74% (p < 0.001); this increase was driven mainly by NACs (increasing from 6.84% to 7.91%, p < 0.001) from 2018 to 2023. The proportion of Efm increased significantly, from 7.7% to 11.11% (p < 0.001). The proportions of all Candida species significantly increased in UTIs (from 24.63% to 28.13%, p < 0.001), especially NACs, while the proportion of Efm also increased significantly in UTIs (from 9.47% to 15.32%, p < 0.001). With respect to the UTIs, the proportion of all the Candida species, C.albicans, and NACs were positively correlated with the amount of systemic antibiotics used. A longer hospital stay was strongly correlated with all Candida HAIs and UTIs, especially NACs. Significantly ecological associations between all the Candida strains and Efm were observed for UTIs. Conclusions: This study revealed that a persistent expansion of NAC infections was associated with increased Efm infections and rising antibiotic consumption. The changes in the proportions of different Candida species in UTIs were most pronounced. These findings support an ecological model in which antibiotic stress and chronic critical illness contribute to the expansion of fungal-bacterial co-infections in the ICU setting and underscore the need for integrated antibiotic management and multi-infection surveillance.