Invasive Candida viswanathii infections in critically ill neonates: clinical challenges and management insights from a case series

Background Candida species continue to be a major cause of invasive fungal infections in neonatal intensive care units, with a growing awareness of new non-Albicans Candida species that pose diagnostic and therapeutic problems in critically ill neonates. Candida viswanathii is an uncommon pathogen with poor clinical evidence, particularly in neonatal critical care units. Methods From April to August 2025, we conducted a case series of five newborns admitted to the neonatal intensive care unit (NICU) of Bambino Gesù Children's Hospital in Rome, Italy, who had bloodstream infections caused by C. viswanathii . Whole-genome sequencing (WGS), chromogenic agar evaluation, MALDI-TOF mass spectrometry, and traditional culture were all used in microbiological identification. Broth microdilution was used to test for antifungal susceptibility. Retrospective clinical data on risk factors, treatment, and results were collected. Results Six cases of candidemia were reported in five critically unwell newborns, the majority of whom were premature or had severe congenital comorbidities. All of the patients had central venous catheters and had been in intensive care for an extended period of time. Initial identification methods misidentified isolates as Candida tropicalis , however molecular research revealed a clonal cluster of C. viswanathii . The BCID2 panel failed to detect the organism. All isolates had higher fluconazole minimum inhibitory concentrations, but echinocandins and amphotericin B had lower MIC values. Systemic echinocandin therapy was the primary treatment, with liposomal amphotericin B added in severe instances, as well as rigorous source control measures such as catheter removal and antifungal lock therapy. Microbiological clearance was documented in all six candidemia episodes. Three patients were discharged, whereas two died because of their underlying cardiopulmonary disease. Conclusions Invasive C. viswanathii infection represents a diagnostic and therapeutic challenge in the NICU. Advanced microbiological techniques, prompt source control, and targeted antifungal therapy are essential for effective management of this emerging pathogen.