Alginate oligosaccharides inhibit fungal cell growth and potentiate the activity of anti-fungals against Candida and Aspergillus spp

Tondervik, Anne, Sletta, Havard, Klinkenberg, Geir, Emanuel, Charlotte, Powell, Lydia C. ORCID: https://orcid.org/0000-0002-8641-0160, Pritchard, Manon F. ORCID: https://orcid.org/0000-0002-5135-4744, Khan, Saira, Craine, Keiron M., Onsoyen, Edvar, Rye, Phil D., Wright, Chris, Thomas, David W. ORCID: https://orcid.org/0000-0001-7319-5820 and Hill, Katja E. ORCID: https://orcid.org/0000-0002-8590-0117 2014. Alginate oligosaccharides inhibit fungal cell growth and potentiate the activity of anti-fungals against Candida and Aspergillus spp. PLoS ONE , e112518. 10.1371/journal.pone.0112518

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Abstract

The oligosaccharide OligoG, an alginate derived from seaweed, has been shown to have anti-bacterial and anti-biofilm properties and potentiates the activity of selected antibiotics against multi-drug resistant bacteria. The ability of OligoG to perturb fungal growth and potentiate conventional antifungal agents was evaluated using a range of pathogenic fungal strains. Candida (n = 11) and Aspergillus (n = 3) spp. were tested using germ tube assays, LIVE/DEAD staining, scanning electron microscopy (SEM), atomic force microscopy (AFM) and high-throughput minimum inhibition concentration assays (MICs). In general, the strains tested showed a significant dose-dependent reduction in cell growth at ≥6% OligoG as measured by optical density (OD600; P<0.05). OligoG (>0.5%) also showed a significant inhibitory effect on hyphal growth in germ tube assays, although strain-dependent variations in efficacy were observed (P<0.05). SEM and AFM both showed that OligoG (≥2%) markedly disrupted fungal biofilm formation, both alone, and in combination with fluconazole. Cell surface roughness was also significantly increased by the combination treatment (P<0.001). High-throughput robotic MIC screening demonstrated the potentiating effects of OligoG (2, 6, 10%) with nystatin, amphotericin B, fluconazole, miconazole, voriconazole or terbinafine with the test strains. Potentiating effects were observed for the Aspergillus strains with all six antifungal agents, with an up to 16-fold (nystatin) reduction in MIC. Similarly, all the Candida spp. showed potentiation with nystatin (up to 16-fold) and fluconazole (up to 8-fold). These findings demonstrate the antifungal properties of OligoG and suggest a potential role in the management of fungal infections and possible reduction of antifungal toxicity.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Dentistry
Subjects:	R Medicine > RK Dentistry
Publisher:	Public Library of Science
ISSN:	1932-6203
Date of First Compliant Deposit:	22 August 2019
Date of Acceptance:	3 October 2014
Last Modified:	06 Jan 2024 03:24
URI:	https://orca.cardiff.ac.uk/id/eprint/68333

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