Bisifusarium Delphinoides, an Emerging Opportunistic Pathogen in a Burn Patient with Diabetes Mellitus

Abstract

An 82-year-old man with diabetes was admitted to the emergency department with a third-degree burn on his left leg. The deep swab specimen from his left leg was cultured on Sabouraud dextrose agar without cycloheximide and incubated at 25 °C for 5 days. On the basis of morphological characteristics and multigene phylogenetic analyses of the internal transcribed spacer region of ribosomal DNA and partial fragments of beta-tubulin and translation elongation factor 1-alpha, the causal agent of fungal skin infection was identified as Bisifusarium delphinoides, which was newly introduced by accommodating a Fusarium dimerum species complex. Thus, we describe here the first case of skin infection caused by B. delphinoides on a burn patient with diabetes mellitus based on morphological observation and molecular analysis.

Keywords: Antifungal susceptibility; FDSC; opportunistic pathogen; phylogenetic analysis.

Figure 1.

Morphological characteristics of Bisifusarium delphinoides. (a) One-week-old colony grown on potato dextrose agar (PDA); (b) one-week-old reverse colony on PDA; (c) Sporodochia; (d–g) lateral phialidic pegs; (h–m) macroconidia and microconidia.

Figure 2.

Phylogenetic tree inferred from the maximum likelihood method for Bisifusarium delphinoides and Fusarium dimerum species complex based on the multigene dataset (ITS, β-tubulin, EF1-α). The numbers above the nodes are the bootstrap values obtained from 1000 replicates. The isolate used in the present study is indicated by an asterisk.