First case of a human Candida berthetii systemic infection in a preterm infant: a case report

Background We report the first case of invasive human infection caused by Candida berthetii in a preterm infant. Case Summary A premature neonate who required prolonged hospitalization, intensive care support, multiple surgical interventions, and broad-spectrum antibiotics developed persistent candidemia due to C. berthetii . Species identification was confirmed through sequencing of the internal transcribed spacer region of ribosomal DNA. Antifungal susceptibility testing, performed using the the European Committee on Antimicrobial Susceptibility Testing (EUCAST) microbroth dilution method, revealed high minimal inhibitory concentrations (MICs) to fluconazole and anidulafungin but low MICs for amphotericin B. Despite switching to liposomal amphotericin B, the infant progressed to multiple organ dysfunction and died. The poor clinical outcome was attributed to both the severity of underlying conditions associated with candidemia and the delay in starting adequate antifungal therapy. Conclusion This case broadens the current understanding of rare yeast pathogens and highlights the critical need for improved diagnostic tools to accurately detect and identify uncommon Candida species. Clinicians should remain vigilant to the emergence of rare yeast pathogens causing fungemia, especially among immunosuppressed hosts undergoing invasive medical procedures and prolonged exposure to broad-spectrum antimicrobials.