Galleria mellonella as alternative model to study the in VIVO efficacy of amphotericin B against Aspergillus terreus infections and its influence on larval immune response

Ref ID: 19551

Author:

E Maurer1*, N Browne2, K Kavanagh2, C Surlis2, C Lass-Flörl1, U Binder1

Author address:

1Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria
2Medical Mycology Unit, Department of Biology, National Institute for Cellular Biotechnology, Maynooth,
Ireland

Full conference title:

6th Advances Against Aspergillosis 2014

Abstract:

Background:
Infections with Aspergillus terreus are of major concern, due to its high likelihood of dissemination
and its intrinsic resistance to amphotericin B (amB). The reason for this resistance is not known yet.
Recently, three clinical isolates, with distinct morphological variations, have been found to be amB
susceptible in vitro.
Methods:
Efficacy of amB treatment and its influence on the larval immune system were investigated in the
invertebrate model G. mellonella. Proteomic analysis of larval haemolymph, haemocyte counts
and post-treatment infection studies were performed. Additionally, putative difference in virulence
potential of the respective isolates was analyzed by correlating survival rates with physiological
attributes and in vitro killing ability of larval haemocytes.
Results:
Treatment with amB only showed success in the groups infected with amB-susceptible strains,
which reflected our in vitro data. Furthermore, amB administration resulted in an increased number
of circulating haemocytes. Proteomic studies showed different protein expression of proteins
which have immune function. Pre-treatment of larvae with amB also increased their resistance to
Staphylococcus aureus infection, indicating a general ability of amB to prime the insect’s immune
system. Larval survival rates differed in the early time points of infection for the various isolates
tested. The amB-resistant isolate T90, showed lowest mortality rates in the early time points of
infection. This is in correlation with a slower germination rate of T90, and the highest fungal damage
caused by haemocytes in vitro.
Conclusion:
This work demonstrated that G. mellonella is a useful model to determine the in vivo efficacy of
amB against A. terreus isolates, and study the virulence potential of different isolates. Our results
showed that antifungal treatment in vivo correlates with in vitro susceptibility data. Furthermore,
one has to be aware of a non specific influence of antifungal drugs on the larval immune response.

Abstract Number: 78

Conference Year: 2014

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

New link: NULL

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