P13. Clinical implications of fluconazole-resistant Candida parapsilosis: the urgent need for enhanced antifungal stewardship (focus project)"

Background: Invasive fungal infections (IFIs) represent a growing health concern due to their morbidity and mortality. The extensive use of antifungal medications contributed to an increase in fungal resistance, particularly among non- albicans Candida species, such as C. parapsilosis (CP). The World Health Organization (WHO) identified fluconazole-resistant C. parapsilosis (FLRCP) as a priority pathogen in the fight against antimicrobial resistance, but data on its clinical impact and risk factors compared to fluconazole-sensitive strains remains limited. This study eval- uates the prevalence, riskfactors,clinical impact and outcomes ofpatients infected with FLRCP. Methods: Thisretrospective,single-centerstudyinvolvedpatientswithinvasivecan- didiasis caused by C. parapsilosis who were admitted to Policlinico Umberto I in Rome between April 2020 and May 2024. Patients were divided into two groups ac- cording to the fluconazole (FLZ) resistance of C. parapsilosis. Minimum inhibitory concentration (MIC) for antifungals were measured using microdilution testing and susceptibility was assessed according to EUCASTclinical breakpoints (resistant to FLZ defined as MIC > 4 mg/L). Data analysis was conducted using R-4.4.0 statis- tical software. Results: In a cohort of 108 patients, the prevalence of FLRCP was 52% (n = 56), with 50% of the cases from the intensive care unit (ICU). The analysis revealed a statis- ticallysignificantassociationbetweenFLRCPandpriorICUadmission(P-value0.01), identified also as the only independent predictive factor for fluconazole resistance (OR 3.65, P-value 0.02). Of note, no significant association was found between FLRCP and previous antifungal therapy, including azoles. Thirty-one percent of pa- tients with FLRCP received liposomal amphotericin B, while 69% were treated with caspofungin, without significant difference between survivors and non-survivors. Resistance to fluconazole did not significantly affect clinical impact or patient out- comes (Table 1). Conclusions: Althoughevidenceonthe clinicalimpact ofFLRCPremainslimited, the increase in cases, as reflected in our prevalence data, highlights the urgent need to define its pathogenic role. Horizontal transmission of the pathogen, suggested by intra-hospital outbreaks involving genetically related clusters and azole-naive pa- tients, emphasizes the need for an Anti-Fungal Stewardship (AFS) program to limit spread and prevent further fungal resistance.