# Identification of causative fungus from sterile abscess using metagenomics followed by in situ hybridization

## TL;DR

This paper describes using metagenomics and in situ hybridization to identify a fungus causing a sterile abscess when traditional methods failed.

## Contribution

The study introduces a novel approach combining deep sequencing and in situ hybridization for fungal identification in sterile abscesses.

## Key findings

- Deep sequencing of the ITS1 region narrowed down candidate fungi in a sterile abscess.
- In situ hybridization confirmed the presence of Trichosporon asahii in the specimen.
- The method successfully identified the causative fungus when blood culture and biopsy failed.

## Abstract

Introduction. Invasive fungal infections require early diagnosis for treatment. Microscopic observation of biopsy and blood culture is the gold standard for the identification of the causative fungus, but it is difficult to identify the causative pathogen by a sterile abscess biopsy.

Case Presentation. We present a case report of breakthrough invasive trichosporonosis in a 65-year-old Japanese male with acute myeloid leukaemia receiving antifungal prophylaxis. Blood cultures showed no fungal growth, and a liver biopsy and a removed spleen with abscess showed fragmented fungi, but no fungal identification was possible. This report demonstrates that retrospective analyses were able to identify the causative fungus.

Conclusion. We narrowed down the candidate fungi by deep sequencing of the ITS1 region of fungal genome and confirmed that the fungus observed in the specimen was Trichosporon asahii by in situ hybridization using a DNA probe targeting 26S rRNA.