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

## TL;DR

A preterm infant died from a rare Candida berthetii infection, highlighting the need for better diagnostic tools for uncommon yeast pathogens.

## Contribution

This is the first reported case of a systemic human infection caused by Candida berthetii in a preterm infant.

## Key findings

- Candida berthetii was identified through ribosomal DNA sequencing in a preterm infant with persistent candidemia.
- Antifungal susceptibility testing showed high resistance to fluconazole and anidulafungin but lower resistance to amphotericin B.
- The infant's death was attributed to severe underlying conditions and delayed effective antifungal treatment.

## Abstract

We report the first case of invasive human infection caused by Candida berthetii in a preterm infant.

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.

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.