Candida Infection Biology – fungal armoury, battlefields ... - FINSysB

Poster number: 41
Dynamic assessment of the antifungal effect of different
plant essential oils by flow cytometry
Crina Maria Saviuc 1,5 , Alexandru Mihai Grumezescu 2 , Coralia Bleotu 1,4 ,
Alina Maria Holban 1 , Otilia Banu 3 , Dan Mihaiescu 2 , Paul Balaure 2 , Mariana
Carmen Chifiriuc 1 , Veronica Lazar 1
1 University of Bucharest, Faculty of Biology, Microbiology University Department; 2 University
Politechnica of Bucharest, Faculty of Applied Chemistry and Materials Science, Organic
Chemistry Department; 3 Institute of Cardiovascular Diseases Prof. C.C. Iliescu, Bucharest;
4 S. Nicolau Institute of Virology, Bucharest; 5 S.C. Biotehnos S.A.
Introduction: The in vitro and in vivo models already demonstrated the microbicidal
as well as the influence of the essential oils on the coordinated expression of the
virulence factors in fungal strains. In the context of incomplete standardization of
susceptibility testing assays, our aim was to evaluate a rapid tool for the
assessment of the antifungal activity of the essential oils using the flow citometry.
Materials and methods: Four essential oils were extracted by microwave assisted
hydrodistilation from different vegetative and reproduction organs of Eugenia
caryophyllata, Anethum graveolens, Mentha piperita and Rosmarinus officinalis.
Chemical composition of the essential oils was established by GC-MS analysis.
The bioassays were performed on five Candida spp. strains recently isolated from
clinical specimens. The qualitative screening of the antimicrobial effect and its
evolution on time was assessed after 1’, 3’, 5’, 15’ and 30’ of contact by viable cell
counts. Minimum inhibitory concentrations (MIC) was assessed by the classical
twofold micro-dilution technique in 96 multiwell plates and also by flow cytometry
after 15’ and 24h of contact.
Results. The essential oils proved to be reach in terpenes and terpenoids in a
balanced composition wich explained the antimicrobial activity. The essential oil
exhibited an early microbicidal effect, with MIC ranging from 0.75 to 7.5µL/mL,
values also confirmed by flow cytometry.
Conclusion. Our results are proving that the tested essential oils exhibited a strong
antifungal effect, probably due to their good diffusion rates and easy contact with
the target structures. Essential oils complex composition and their volatility raise
specific problems in susceptibility testing, due to their poor solubility, unknown
diffusion pattern in solid media and vapor phase effect. In this context flow
cytometry technique could be considered a reliable tool for evaluating the antifungal
activity of this type of complex mixtures.
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