Aspergillus fumigatus and Aspergillus terreus virulence in the Galleria mellonella insect model

Ref ID: 19613

Author:

K Dunne1,2*, J Renwick2, TR Rogers1, P Murphy2

Author address:

1Department of Clinical Microbiology, Sir Patrick Dun Laboratory, Trinity College Dublin, St. James’
Hospital, Dublin, Ireland
2Department of Clinical Microbiology, Trinity Centre, Trinity College Dublin, Tallaght Hospital, Dublin,
Ireland

Full conference title:

6th Advances Against Aspergillosis 2014

Abstract:

Introduction:
Aspergillus spp. have emerged as important pathogens in Cystic Fibrosis (CF) patients, most
commonly causing Allergic Bronchopulmonary Aspergillosis (ABPA). However many CF patients
may be colonised without displaying any signs or symptoms of ABPA. A. fumigatus and A. terreus
are among the most commonly isolated fungal pathogens from CF patients. In this study the virulence
of a collection of A. fumigatus and A. terreus strains isolated from CF patients were compared using
the Galleria mellonella insect model.
Methods:
A. fumigatus (n=14) and A. terreus (n=7) isolates from CF patients were collected. All isolates
from the study were confirmed as A. fumigatus or A. terreus by sequencing of the ITS region.
G. mellonella were inoculated with a range of concentrations of Aspergillus conidia and larval
survival was monitored over 7 days. Virulence was compared for all isolates and the lethal dose 50
(LD50) was calculated for all isolates.
Results and Conclusions:
The A. fumigtaus isolates showed variable levels of virulence in the Galleria model. Likewise
the A. terreus isolates showed different levels of virulence. However no statistical difference was
observed between A. fumigatus isolates. One A. terreus isolate (AT5429) was significantly more
virulent than the others (p<0.001). A. fumigatus isolates caused a significantly higher mortality than A. terreus with the exception of one A. terreus isolate (AT5429) (p<0.01). The A. terreus isolate AT5429 caused a similar level of mortality to that of the A. fumigatus isolates suggesting that some A. terreus strains may be as virulent as A. fumigatus. LD50 calculations of these isolates revealed no significant difference between A. fumigatus isolates. However LD50 calculations for A. terreus isolates showed a significant difference between all isolates. There was a significant difference between LD50 calculations for A. fumigatus and A. terreus isolates with the exception of one A. terreus isolate (AT5429). Administration of Amphotericin B after exposure to A. fumigatus or A. terreus significantly reduced mortality in the G. mellonella insect model. These results demonstrate that different strains of A. fumigatus and A. terreus have varying effects on G. mellonella. Monitoring the specific strains of A. fumigatus and A. terreus colonising the airways of CF patients may be of clinical benefit.

Abstract Number: 138

Conference Year: 2014

Link to conference website: http://www.AAA2014.org

New link: NULL

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