Invasive mycosis due to species of Blastobotrys in immunocompromised patients with reduced susceptibility to antifungals

Abstract

Cases of invasive mycosis due to Blastobotrys serpentis and B. proliferans identified by sequencing in a preterm patient and a rhabdomyosarcoma patient, respectively, are reported. Both species revealed elevated fluconazole and echinocandin MICs by the CLSI broth microdilution method. Additionally, B. serpentis exhibited high amphotericin B MICs, thus posing serious therapeutic challenges.

FIG 1

The drugs administered and the clinical course of a case 1 neonate with invasive mycosis due to Blastobotrys serpentis. +ve, positive; ET, endotracheal aspirate.

FIG 2

(a) Slide cultures on malt extract agar of 5 days growth at 28°C of the Blastobotrys serpentis (VPCI 568/P/13) isolate collected from blood culture of case 1, showing well-differentiated pseudohyphae with abundant blastoconidia. Septate hyphae were not observed. Magnification, ×1,000. (b) Slide cultures on malt extract agar of 7 days growth at 28°C of the Blastobotrys proliferans (VPCI 573/P/13) isolate collected from blood culture of case 2, showing conidiophores bearing pear-shaped mother cells and crowned with secondary conidia (downward arrow) and lateral conidia (upward arrows). Magnification, ×400. (c) Thick-walled, terminal, and intercalary chlamydospores (arrows). Magnification, ×1,000.

FIG 3

Phylogenetic tree based on D1/D2 sequences of the type/reference strains of B. serpentis CBS 10541^T and W113B, B. proliferans CBS 522.75^T, B. chiropterorum CBS 6064^T, and Trichomonascus ciferrii CBS 5295, obtained by using maximum-likelihood phylogenetic analyses with 2,000 bootstrap replications.