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. 2020 Aug;77(8):1373-1380.
doi: 10.1007/s00284-020-01927-2. Epub 2020 Mar 2.

Production of Mannosylerythritol Lipids (MELs) to be Used as Antimicrobial Agents Against S. aureus ATCC 6538

Chiara Ceresa  1 , Simon Hutton  2 , Marta Lajarin-Cuesta  2 , Robert Heaton  2 , Iain Hargreaves  2 , Letizia Fracchia  1 , Mayri A Díaz De Rienzo  3
Affiliations

Production of Mannosylerythritol Lipids (MELs) to be Used as Antimicrobial Agents Against S. aureus ATCC 6538

Chiara Ceresa et al. Curr Microbiol. 2020 Aug.

Abstract

Antimicrobial resistance (AMR) is a current major health issue, both for the high rates of resistance observed in bacteria that cause common infections and for the complexity of the consequences of AMR. Pathogens like Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Mycobacterium tuberculosis among others are clear examples of antibiotic-resistant threats. Biosurfactants have recently emerged as a potential new generation of anti-adhesive and anti-biofilm agents; mannosylerythritol lipids (MELs) are biosurfactants produced by a range of fungi. A range of structural variants of MELs can be formed and the proportion of each isomer in the fermentation depends on the yeast used, the carbon substrate used for growth and the duration of the fermentation. In order to allow assessment of the possible functions of MELs as antimicrobial molecules, small quantities of MEL were produced by controlled fermentation. Fermentations of the yeast Pseudozyma aphidis using rapeseed oil as a carbon source yielded up to 165 gMELs/kgSubstrate. The MELs formed by this strain was a mixture of MEL-A, MEL-B, MEL-C and MEL-D. The MELs produced were tested against S. aureus ATCC 6538 on pre-formed biofilm and on co-incubation biofilm experiments on silicone discs; showing a disruption of biomass, reduction of the biofilm metabolic activity and a bacteriostatic/bactericidal effect confirmed by a release of oxygen uptake [Formula: see text], the reduction of citrate synthase activity and scanning electron microscopy. The results show that MELs are promising antimicrobial molecules for biomedical technological applications that could be studied in detail in large-scale systems and in conjunction with animal tissue models.

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Figures

Fig. 1
Fig. 1
Molecular structure of mannosylerythritol lipids. The length and saturation of the fatty acid residues depend on the substrate and microorganism used. MEL-A → R1: Acetyl, R2: Acetyl; MEL-B → R1: Acetyl, R2: H; MEL-C → R1: H, R2: Acetyl; MEL-D → R1: H, R2: H
Fig. 2
Fig. 2
Identification of MELs by different analytical methods. a TLC obtained from MELs partially purified (FFA free fatty acids, TRI tri-acylated MELs). b ESI–MS spectrum from MELs partially purified
Fig. 3
Fig. 3
Effect of MELs at different concentration on S. aureus ATCC 6538 biofilm formation. a 24 h and b 48 h, using crystal violet as an indicator. Assays were carried out in triplicate and the experiments were repeated three times (n = 9)
Fig. 4
Fig. 4
Metabolic activity of S. aureus ATCC 6538 biofilms in the presence of MELs at different concentration on at a 24 h and b 48 h, using MTT as an indicator of metabolic activity. Assays were carried out in triplicate and the experiments were repeated three times (n = 9)
Fig. 5
Fig. 5
Oxygen consumption of S. aureus ATCC 6538 biofilms after 30-min treatment, using different concentrations of MELs. The relative concentration of dissolved oxygen is expressed as the percentage of saturation concentration versus time after addition of the different treatments. Concentrations used are indicated
Fig. 6
Fig. 6
Effect of various concentrations of MELs on HaCaT cell viability. Cell line seeded with different treatments, and viability determined by MTT assay. Positive control higher percentage of viable cells: PBS 1×. Negative control lower percentage of viable cells: SDS 0.5 mg/mL
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References

    1. Howard SJ, Catchpole M, Watson J, Davies SC. Antibiotic resistance: global response needed. Lancet Infect Dis. 2013;13(12):1001–1003. doi: 10.1016/S1473-3099(13)70195-6. - DOI - PubMed
    1. Schürch AC, van Schaik W. Challenges and opportunities for whole-genome sequencing-based surveillance of antibiotic resistance. Ann NY Acad Sci. 2017;1388(1):108–120. doi: 10.1111/nyas.13310. - DOI - PubMed
    1. Rossolini GM, Arena F, Pecile P, Pollini S. Update on the antibiotic resistance crisis. Curr Opin Pharmacol. 2014;18:56–60. doi: 10.1016/j.coph.2014.09.006. - DOI - PubMed
    1. Lewis K. Riddle of biofilm resistance. Antimicrob Agents Chemother. 2001;45(4):999–1007. doi: 10.1128/aac.45.4.999-1007.2001. - DOI - PMC - PubMed
    1. Lebeaux D, Ghigo JM, Beloin C. Biofilm-related infections: bridging the gap between clinical management and fundamental aspects of recalcitrance toward antibiotics. Microbiol Mol Biol Rev. 2014;78(3):510–543. doi: 10.1128/MMBR.00013-14. - DOI - PMC - PubMed

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