Teresa Nascimento ^1* Joao Inacio ² Daniela Guerreiro ¹ Priscila Diaz ³ Patrícia Patrício ⁴ Luis Proença ¹ Cristina Toscano ⁵ Helena Barroso ¹

• ¹ Egas Moniz School of Health and Science, Almada, Portugal
• ² University of Brighton, Brighton, United Kingdom
• ³ Hospital Prof. Doutor Fernando Fonseca, EPE, Amadora, Portugal
• ⁴ Hospital Beatriz Ângelo, Loures, Portugal
• ⁵ Departamento de Patologia Clínica, Centro Hospitalar Lisboa Ocidental, Lisboa, Portugal

Introduction: Candida auris is an emerging pathogen that represents a worldwide health problem due to its global expansion, multidrug resistance, and difficult laboratory identification. Among the risk factors for colonization/infection by C. auris, stay in Intensive Care Units (ICU) stands out. This prospective multicenter study aimed to monitor the trend of local epidemiology of Candida spp. and unveil the prevalence of C. auris.From 2020 to 2022, axillar/inguinal swabs were collected from adults patients at three points: upon admission (D1), on the 5 th (D5) and 8 th (D8) day of their ICU stay. We employed culture-based screening methods combined with molecular techniques to identify Candida spp. down to the species level. Specific screening for Candida auris was conducted using a real-time PCR assay in combination with an improved selective culture medium, Mannitol Salt Agar Auris (MSAA). To validate the effectiveness of MSAA, a collection of reference C. auris strains representing the four major geographical clades was used.We enrolled 675 patients and a total of 355 Candida isolates were retrieved from the 988 swab samples collected. From those, 185/355 (52.1%) were identified as C. albicans and 170/355 (47.9%) as non-albicans Candida (NAC). MSAA medium showed a specificity of 94.8% albeit C. auris was not detected in this cohort. The dynamics of Candida spp. colonisation by ICU were significantly at the three-point collections. Upon admission, C. albicans was associated upon with BAH ICU (p=0.003) and C. tropicalis with general FFH ICU (p=0.006). C. parapsilosis and C. lusitaniae were associated with FFH ICUs, respectively with general ICU at D5 (p= 0.047) and surgical ICU at D8 (p= 0.012). The dynamics of NAC colonisation by ICU were significantly different at D1 (p= 0.011), D5 (p= 0.047) and D8 (p= 0.012).We developed and implemented a screening protocol for C. auris while uncovering the colonization patterns of Candida in the ICU. Our findings contribute to optimizing overall patient management, ensuring that ICU protocols are resilient and adaptive to emerging fungal threats.