A newly developed assay to study the minimum inhibitory concentration of Satureja spinosa essential oil

Chorianopoulos, Nikos; Lambert, R. H.; Skandamis, Panagiotis; Evergetis, Epameinondas; Haroutounian, Serkos A.; Nychas, George‐John E.

doi:10.1111/j.1365-2672.2006.02827.x

Cited by 40 publications

(51 citation statements)

References 40 publications

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“…For each bacteria density we fit the positive droplet fraction data by the Gompertz function 23,24 . Then we calculate the MIC as the antibiotic concentration value where Gompertz fit crosses the 0.5 viability fraction in droplets ( Fig 2G).…”

Section: Main Textmentioning

confidence: 99%

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“Antibiotic inhibition of bacteria growth in droplets reveals heteroresistance pattern at the single cell level”

Scheler

Makuch

Debski

et al. 2018

Preprint

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Heteroresistance is a phenomenon where isogenic bacteria population exhibits a diverse antibiotic resistance pattern at sub-population or single cell level. The sub-populations with higher resistance can remain undetected with conventional diagnostics which makes them subsequently harder to treat. Such surviving phenotypically heterogeneous sub-populations are also a potential hotbed for novel mutations, thus increasing the resistance permanently in bacteria. Droplet microfluidics gives tools for high-throughput analysis of bacteria and their response to antibiotics at single cell level, which is difficult to obtain with traditional agar plate technologies. In here we show for the first time the precise digital quantification of drug resistance profile in isogenic population at single cell level. We also see that the inhibiting amount of drug per bacteria remains quite stable regardless of bacteria density. Interestingly, the bacteria clump together preferably near these sub-inhibitory conditions. The technology and findings we describe here provide novel quantitative insight into the heteroresistance which is a key step in understanding the pathways leading to drug resistance. This knowledge is crucial in the context of global drug resistance threat as it can help us to find tools to prevent further escalation of drug resistance.

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Section: Main Textmentioning

confidence: 99%

“…1C from the main text: the normalized fraction almost always decreases with the antibiotic concentration. For each bacterial density we fit the data by the Gompertz function 23,24 , which is a 2-parameter function:…”

Section: Mic Calculationmentioning

confidence: 99%

“Antibiotic inhibition of bacteria growth in droplets reveals heteroresistance pattern at the single cell level”

Scheler

Makuch

Debski

et al. 2018

Preprint

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“…The regression analysis was performed by using the Generalised Reduced Gradient algorithm (Excel solver) and the least squares optimisation where the objective function is expressed as a sum of squares. The minimum inhibitory concentration (MIC), defined as the concentration above which no growth is observed relative to the control and the non-inhibitory concentration (NIC) defined as the concentration below which normal visible growth is observed (Chorianopoulos et al 2006), were estimated from the LPM as follows (Chorianopoulos et al 2006; Guiller et al 2007): …”

Section: Calculation (Quantitative Assessment Of the Inhibitory Concementioning

confidence: 99%

Assessing the efficacy of zinc oxide nanoparticles against Penicillium expansum by automated turbidimetric analysis

2017

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Public concerns about food safety have triggered a worldwide implementation of new legislations aimed at banning many of the most popular food conventional antifungal treatments. There is therefore an urgent need to identify novel and safer solutions to prevent fungal contamination of food. The antifungal effect of zinc oxide nanoparticles (ZnO NPs) against the postharvest pathogenic fungus Penicillium expansum has been investigated in this study. An automated turbidimetric assay, with a standard 96-well microplate, has been developed and optimised regarding the selection of the inoculum size in order to collect sequential optical density measurements. Data were processed by the updated version of the Lambert Pearson model to estimate the minimum inhibitory concentration and the non-inhibitory concentration values which were found to be 9.8 and 1.8 mM (i.e. 798 and 147 ppm), respectively. The current results show that turbidimetry is a reliable technique for assessing the antifungal activity of metal nanoparticles and that zinc oxide (ZnO) is an effective fungicide which can be potentially used to control food safety.

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“…(2008). Some studies have reported using two inoculation levels (Chorianopoulos et al. 2006; Santiesteban‐López et al.…”

Section: Introductionmentioning

confidence: 99%

An Innovative Microplate Assay to Facilitate the Detection of Antimicrobial Activity in Plant Extracts

Sultanbawa¹,

Cusack²,

Currie³

et al. 2009

Rapid Methods Automation Mic

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A microplate assay was modified for the detection of antimicrobial activity in plant extracts. The aim was to develop an in vitro assay that could rapidly screen plant extracts to provide quantitative data on inhibition of microbial growth. A spectrophotometric assay using a microplate with serial dilutions of the plant extract and the bacteria was developed. Two bacteria, Staphylococcus aureus and Escherichia coli, were used for this study. Essential oils, oregano (Origanum vulgare) and lemon myrtle (Backhousia citriodora), and three active components carvacrol, thymol and citral were evaluated. The reproducibility of the assay was high, with correlation coefficients (r2) of the replicates of lemon myrtle and oregano with S. aureus and E. coli between 0.9321 and 0.9816. Similarly, r2 values for carvacrol, thymol and citral were between 0.8455 and 0.9814. This assay could also be used to measure antimicrobial activity in plant extracts which vary in pH and color. PRACTICAL APPLICATIONS This research could be used for the quantitative determination of antimicrobial activity in plant extracts. As inhibition of growth is expressed as a percentage from 0 to 100, this method could also be used to study synergies within plant extracts to enhance antimicrobial activity for future studies. When plant extracts are used in food as natural preservatives, the challenge is to use a concentration that does not interfere with the flavor of the food product. In general, the amount of plant extract required to extend the storage life of food is greater than that required to produce an acceptable flavor. The advantage of knowing the percent inhibition relates to the effect of synergies where the inhibitions less than 100% can be enhanced with other antimicrobial plant extracts, thereby reducing the amount of plant extract required.

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A newly developed assay to study the minimum inhibitory concentration of Satureja spinosa essential oil

Cited by 40 publications

References 40 publications

“Antibiotic inhibition of bacteria growth in droplets reveals heteroresistance pattern at the single cell level”

“Antibiotic inhibition of bacteria growth in droplets reveals heteroresistance pattern at the single cell level”

Assessing the efficacy of zinc oxide nanoparticles against Penicillium expansum by automated turbidimetric analysis

An Innovative Microplate Assay to Facilitate the Detection of Antimicrobial Activity in Plant Extracts

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