Planta Med 2019; 85(18): 1523-1524
DOI: 10.1055/s-0039-3400020
Main Congress Poster
Poster Session 2
© Georg Thieme Verlag KG Stuttgart · New York

Complexity – another bit of the puzzle in the standardization of testing methods to determine efficacy of natural products

AM Keaveney
1   Department Biological Sciences, Cork Institute of Technology,, Rossa Ave., Cork, Ireland
,
F Mahar
1   Department Biological Sciences, Cork Institute of Technology,, Rossa Ave., Cork, Ireland
,
B Lucey
1   Department Biological Sciences, Cork Institute of Technology,, Rossa Ave., Cork, Ireland
,
A Furey
2   Department Physical Sciences, Cork Institute of Technology,, Rossa Ave., Cork, Ireland
› Author Affiliations
Further Information

Publication History

Publication Date:
20 December 2019 (online)

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Both EUCAST and CLSI specify Mueller Hinton agar for evaluating antimicrobial susceptibility using the Kirby-Bauer disc-diffusion method [1], [2]. While a number of factors can affect the results obtained (for example, how the bacteria is applied to the agar or depth of agar) neither organization recommends a particular manufacturer of the Mueller Hinton agar (M-H). Antimicrobial susceptibility is evaluated in terms of specific breakpoints (MIC and inhibition diameter) for antimicrobial agents (antibiotics) at specified dosages.

This research investigated any variability in results of antimicrobial susceptibility testing of natural products. M-H from three different manufacturers was investigated using two control strains of Staphylococcus aureus, namely ATCC 29213 and ATCC 25923 using the well-diffusion method.

The results showed that the source of the M-H had significant effects on the antimicrobial bioassay.

In conclusion, the source of the Mueller Hinton agar used in antimicrobial susceptibility testing would appear to be another variable that needs to be considered when investigating the antimicrobial properties of natural products.