Purpose: Gliotoxin is an epidithiodioxopiperazine mycotoxin that is secreted by a variety of fungi such as Aspergillus fumigatus. Aspergillus fumigatus is a pathogenic fungus and is known to be a common cause of invasive aspergillosis. In co-infection, bacteria derived components in cell walls have been reported to induce gliotoxin production by fungi. The aim of this study was to determine whether bacteria associated molecules induce an increase in gliotoxin production in clinical Aspergillus fumigatus isolates
Methods: Twelve isolates from respiratory infections were were grown in gliotoxin media for 7 days and analysed for gliotoxin production using high performance liquid chromatography (HPLC-DAD). The strains which were found to produce gliotoxin were further co-inoculated cell wall components, (lipoteichoic acid, lipopolysaccharides and peptidoglycan (5 µg) each) and incubated for eight days and analysed by HPLC for the production of gliotoxin. The antimicrobial activity of gliotoxin was also tested against a range of gram negative and positive bacteria using the agar disk diffusion method in order to understand the secondary reaction by fungi to presence of bacterial or its components.
Results: Six of A. fumigatus isolates were shown to produce gliotoxin were found to produce gliotoxin with the highest concentration being 221.1 µg/ml. Cell wall components, lipoteichoic acid, lipopolysaccharides and peptidoglycan (5 µg) each were added to shake flask, incubated for eight days and analysed by HPLC for the production of gliotoxin. The comparison highlighted the effect of the bacterial components on gliotoxin production. A concentration 0.5 µg/ml of gliotoxin revealed inhibition ranging from 4 mm to 8 mm on the different bacteria.
Conclusion: An increase in gliotoxin production affected by the different cell wall components is significant in inducing secondary metabolite production during bacterial co-infection which may multiply the effect of the infection and might lead to potential cancer cells.
Full conference title:
- AAA 8th (2018)