Changing Epidemiology of Candida spp. Causing Bloodstream Infections in a Tertiary Hospital in Northern Greece: Appearance of Candida auris .

Introduction: The epidemiology of candidemia has shifted in the past few decades; drug-resistant non-albicans Candida species have become more prevalent worldwide. The aim of this retrospective study was to determine the epidemiology of Candida species isolated from hospitalized neonates, children and adults, and to investigate a potential changing susceptibility pattern in a large general tertiary hospital.
Methods: All unique Candida strains isolated from candidemia cases between 1 January 2020 and 15 October 2024 were identified, and their susceptibility profile was characterized. The distribution pattern in different ward types (medical, surgical, pediatric and ICU) was recorded. Cumulative annual susceptibility profiles were compared.
Results: Candidemia incidence increased during the COVID-19 pandemic, from 0.63/1000 patient-days in 2020 to 0.96/1000 patient-days in 2022, and has since slightly decreased (0.83 and 0.89 in 2023 and 2024, respectively). Candidemia-associated mortality was high (>50%) in 2020 and peaked during the pandemic. During the study period, Candida parapsilosis remained the most frequent Candida spp. However, since the first isolation of Candida auris from the bloodstream in late 2022, and despite intense infection control measures taken, its frequency sharply climbed to the second position after only C. parapsilosis in the first 10 months of 2024 (33.6% vs. 25.2% for C. parapsilosis and 21.0% for C. albicans ). While C. albicans has remained highly susceptible to fluconazole (1% resistance rate), C. parapsilosis manifested significant resistance to fluconazole during 2022-2024 (52%). C. auris was universally resistant to azoles and one isolate also resistant to echinocandins.
Conclusions: A high prevalence of azole resistance of C. parapsilosis, the most frequently isolated Candida species, persists, and a significant rise of C. auris was recorded in nosocomial bloodstream infections with severe implications on public health.