Limits...
Analyzing the antibacterial effects of food ingredients: model experiments with allicin and garlic extracts on biofilm formation and viability of Staphylococcus epidermidis.

Wu X, Santos RR, Fink-Gremmels J - Food Sci Nutr (2015)

Bottom Line: To demonstrate different effects of garlic extracts and their main antibiotic substance allicin, as a template for investigations on the antibacterial activity of food ingredients.Biofilm density was impaired significantly at a concentration of 0.78 μg/mL allicin.The current experimental protocol has proven to be a valid approach to characterize the antimicrobial activity of traditional food ingredients.

View Article: PubMed Central - PubMed

Affiliation: Division Veterinary Pharmacology, Pharmacotherapy and Toxicology, Faculty of Veterinary Medicine, Institute for Risk Assessment Sciences, Utrecht University Utrecht, The Netherlands.

ABSTRACT
To demonstrate different effects of garlic extracts and their main antibiotic substance allicin, as a template for investigations on the antibacterial activity of food ingredients. Staphylococcus epidermidis ATCC 12228 and the isogenic biofilm-forming strain ATCC 35984 were used to compare the activity of allicin against planktonic bacteria and bacterial biofilms. The minimal inhibitory concentration (MIC) and the minimum biofilm inhibitory concentration (MBIC) for pure allicin were identical and reached at a concentration of 12.5 μg/mL. MBICs for standardized garlic extracts were significantly lower, with 1.56 and 0.78 μg/mL allicin for garlic water and ethanol extract, respectively. Biofilm density was impaired significantly at a concentration of 0.78 μg/mL allicin. Viability staining followed by confocal laser scanning microscopy showed, however, a 100% bactericidal effect on biofilm-embedded bacteria at a concentration of 3.13 μg/mL allicin. qRT-PCR analysis provided no convincing evidence for specific effects of allicin on biofilm-associated genes. Extracts of fresh garlic are more potent inhibitors of Staphylococcus epidermidis biofilms than pure allicin, but allicin exerts a unique bactericidal effect on biofilm-embedded bacteria. The current experimental protocol has proven to be a valid approach to characterize the antimicrobial activity of traditional food ingredients.

No MeSH data available.


Related in: MedlinePlus

Relative mRNA expression (mean ± SEM) of selected biofilm-related genes in biofilm bacteria (A) and persister cells in suspension (B). Down- and upregulation of gene expression (marked by dashed lines) were considered significant when the relative expression was decreased or increased ≥4 folds.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4376410&req=5

fig06: Relative mRNA expression (mean ± SEM) of selected biofilm-related genes in biofilm bacteria (A) and persister cells in suspension (B). Down- and upregulation of gene expression (marked by dashed lines) were considered significant when the relative expression was decreased or increased ≥4 folds.

Mentions: To gain further insight into the effects of allicin on S. epidermidis ATCC 35984 biofilm, the expression of selected genes that mark different phases of biofilm formation was analyzed in parallel in biofilm-adhered bacteria, as well as in nonadhered, persister cells present in the supernatant above the biofilm. In the biofilm-embedded bacteria (Fig.6A), allicin exposure resulted in a downregulation of aap and icaA, which are associated with the adhesion and bacterial accumulation in a biofilm. In persister cells (Fig.6B), aap expression was not influenced by allicin, but icaA was downregulated and a concentration-dependent increase in rsbU, a bacterial stress factor, was visible.


Analyzing the antibacterial effects of food ingredients: model experiments with allicin and garlic extracts on biofilm formation and viability of Staphylococcus epidermidis.

Wu X, Santos RR, Fink-Gremmels J - Food Sci Nutr (2015)

Relative mRNA expression (mean ± SEM) of selected biofilm-related genes in biofilm bacteria (A) and persister cells in suspension (B). Down- and upregulation of gene expression (marked by dashed lines) were considered significant when the relative expression was decreased or increased ≥4 folds.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4376410&req=5

fig06: Relative mRNA expression (mean ± SEM) of selected biofilm-related genes in biofilm bacteria (A) and persister cells in suspension (B). Down- and upregulation of gene expression (marked by dashed lines) were considered significant when the relative expression was decreased or increased ≥4 folds.
Mentions: To gain further insight into the effects of allicin on S. epidermidis ATCC 35984 biofilm, the expression of selected genes that mark different phases of biofilm formation was analyzed in parallel in biofilm-adhered bacteria, as well as in nonadhered, persister cells present in the supernatant above the biofilm. In the biofilm-embedded bacteria (Fig.6A), allicin exposure resulted in a downregulation of aap and icaA, which are associated with the adhesion and bacterial accumulation in a biofilm. In persister cells (Fig.6B), aap expression was not influenced by allicin, but icaA was downregulated and a concentration-dependent increase in rsbU, a bacterial stress factor, was visible.

Bottom Line: To demonstrate different effects of garlic extracts and their main antibiotic substance allicin, as a template for investigations on the antibacterial activity of food ingredients.Biofilm density was impaired significantly at a concentration of 0.78 μg/mL allicin.The current experimental protocol has proven to be a valid approach to characterize the antimicrobial activity of traditional food ingredients.

View Article: PubMed Central - PubMed

Affiliation: Division Veterinary Pharmacology, Pharmacotherapy and Toxicology, Faculty of Veterinary Medicine, Institute for Risk Assessment Sciences, Utrecht University Utrecht, The Netherlands.

ABSTRACT
To demonstrate different effects of garlic extracts and their main antibiotic substance allicin, as a template for investigations on the antibacterial activity of food ingredients. Staphylococcus epidermidis ATCC 12228 and the isogenic biofilm-forming strain ATCC 35984 were used to compare the activity of allicin against planktonic bacteria and bacterial biofilms. The minimal inhibitory concentration (MIC) and the minimum biofilm inhibitory concentration (MBIC) for pure allicin were identical and reached at a concentration of 12.5 μg/mL. MBICs for standardized garlic extracts were significantly lower, with 1.56 and 0.78 μg/mL allicin for garlic water and ethanol extract, respectively. Biofilm density was impaired significantly at a concentration of 0.78 μg/mL allicin. Viability staining followed by confocal laser scanning microscopy showed, however, a 100% bactericidal effect on biofilm-embedded bacteria at a concentration of 3.13 μg/mL allicin. qRT-PCR analysis provided no convincing evidence for specific effects of allicin on biofilm-associated genes. Extracts of fresh garlic are more potent inhibitors of Staphylococcus epidermidis biofilms than pure allicin, but allicin exerts a unique bactericidal effect on biofilm-embedded bacteria. The current experimental protocol has proven to be a valid approach to characterize the antimicrobial activity of traditional food ingredients.

No MeSH data available.


Related in: MedlinePlus