# From black particles to molecular proof: PD-associated peritonitis by Daldinia eschscholtzii

## TL;DR

A rare case of peritoneal dialysis peritonitis caused by a black mold called Daldinia eschscholtzii is reported, highlighting the importance of early detection through visual signs like black particles.

## Contribution

This is the first documented case of PD-associated peritonitis caused by Daldinia eschscholtzii, emphasizing the role of black particles as an early warning sign.

## Key findings

- Black particles in the PD transfer set were linked to a dematiaceous mold infection.
- Daldinia eschscholtzii was identified through multi-locus sequencing and galactomannan positivity.
- Early visual signs like black particles can indicate fungal peritonitis before symptoms worsen.

## Abstract

Fungal infection in peritoneal dialysis (PD) is rare but devastating, especially with filamentous molds. We report a 60-year-old man on continuous ambulatory PD who presented with black particulate material in the PD transfer set and mild abdominal discomfort without cloudy effluent. PD effluent showed low-grade neutrophilic inflammation, and microscopy revealed dematiaceous septate hyphae. A slow-growing pigmented mold, initially misidentified as Cladosporium, was definitively identified as Daldinia eschscholtzii by multi-locus sequencing, supported by galactomannan positivity. This first report of PD-associated peritonitis due to D. eschscholtzii positions black intraluminal particles as an early visual warning sign of PD catheter-associated dematiaceous mold infection, underscoring the need for integrated mycological diagnostics before overt peritonitis develops.