Rapid analysis of bacterial contamination of tap water using isothermal calorimetry

Maskow, Thomas; Wolf, Katrin; Kunze, Wolfgang; Enders, Sabine; Harms, Hauke

doi:10.1016/j.tca.2012.06.002

Cited by 26 publications

(24 citation statements)

References 39 publications

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“…Attempts of more detailed descriptions have been made, with no further development of the argument or an in-depth investigation [1]. The closed batch cell experimental conditions used within the present study are different from either continuous, oxygen concentration controlled flow [24] experiments, or “N 2 fumigated” [2] (i.e. flushed suspension) batch ones.…”

Section: Resultsmentioning

confidence: 99%

“…As a result, as few as 10,000-100,000 active bacterial cells in a culture are sufficient to produce a real-time signal, dynamically related to the number of cells present and their activity [1]. For aerobic growth, a recent contribution [2] used an extension of the above range to 1-4 pW per cell based on earlier reported results [3], thus pointing to a range of calorimetric detection of 6250 – 25000 cells per ml. Therefore, microcalorimetry may be considered as one of the most sensitive tools in the study of bacterial growth.…”

Section: Introductionmentioning

confidence: 99%

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Comparative analysis of Staphylococcus aureus and Escherichia coli microcalorimetric growth

et al. 2013

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BackgroundMicrocalorimetric bacterial growth studies have illustrated that thermograms differ significantly with both culture media and strain. The present contribution examines the possibility of discriminating between certain bacterial strains by microcalorimetry and the qualitative and quantitative contribution of the sample volume to the observed thermograms. Growth patterns of samples of Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) were analyzed. Certain features of the thermograms that may serve to distinguish between these bacterial strains were identified.ResultsThe thermograms of the two bacterial strains with sample volumes ranging from 0.3 to 0.7 ml and same initial bacterial concentration were analyzed. Both strains exhibit a roughly 2-peak shape that differs by peak amplitude and position along the time scale. Seven parameters corresponding to the thermogram key points related to time and heat flow values were proposed and statistically analyzed. The most relevant parameters appear to be the time to reach a heat flow of 0.05 mW (1.67 ± 0.46 h in E. coli vs. 2.99 ± 0.53 h in S. aureus, p < 0.0001), the time to reach the first peak (3.84 ± 0.5 h vs. 5.17 ± 0.49 h, p < 0.0001) and the first peak value (0.19 ± 0.02 mW vs. 0.086 ± 0.012 mW, p < 0.0001). The statistical analysis on 4 parameters of volume-normalized heat flow thermograms showed that the time to reach a volume-normalized heat flow of 0.1 mW/ml (1.75 ± 0.37 h in E. coli vs. 2.87 ± 0.65 h in S. aureus, p < 0.005), the time to reach the first volume-normalized peak (3.78 ± 0.47 h vs. 5.12 ± 0.52 h, p < 0.0001) and the first volume-normalized peak value (0.35 ± 0.05 mW/ml vs. 0.181 ± 0.040 mW/ml, p < 0.0001) seem to be the most relevant. Peakfit® decomposition and analysis of the observed thermograms complements the statistical analysis via quantitative arguments, indicating that: (1) the first peak pertains to a faster, “dissolved oxygen” bacterial growth (where the dissolved oxygen in the initial suspension acts as a limiting factor); (2) the second peak indicates a slower “diffused oxygen” growth that involves transport of oxygen contained in the unfilled part of the microcalorimetric cell; (3) a strictly fermentative growth component may slightly contribute to the observed complex thermal signal.ConclusionThe investigated strains of Staphylococcus aureus and Escherichia coli display, under similar experimental conditions, distinct thermal growth patterns. The two strains can be easily differentiated using a selection of the proposed parameters. The presented Peakfit analysis of the complex thermal signal provides the necessary means for establishing the optimal growth conditions of various bacterial strains. These conditions are needed for the standardization of the isothermal microcalorimetry method in view of its further use in qualitative and quantitative estimation of bacterial growth.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparative analysis of Staphylococcus aureus and Escherichia coli microcalorimetric growth

et al. 2013

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“…Such systems could additionally be used for other mandatory microbiological assessments, for example, the determination of the degree of water contamination (Maskow et al . ).…”

Section: Discussionmentioning

confidence: 97%

“…; Maskow et al . ). In this work, we will evaluate IMC as a possible alternative for the above described sterility control and highlight its advantages, drawbacks and potential impact on existing procedures.…”

Section: Introductionmentioning

confidence: 97%

An alternative sterility assessment for parenteral drug products using isothermal microcalorimetry

et al. 2017

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“…A higher quality factor allows for better resolution of detection (Shuchen et al, 2013;Walton et al, 1993). Pyro-electric biosensors/ calorimetric biosensors: Calorimetric biosensors measure the change in temperature of the solution containing the analyte, following enzyme action and interpret it in terms of the analyte concentration in the solution (Maskow et al, 2012;Kirchner et al, 2012). The sensitivity (10 -4 M) and the range (10 -4 -10 -2 M) of such biosensors are quite low for most applications.…”

Section: Principlementioning

confidence: 99%

Myco-toxins Monitoring Device and their Management Strategies through Detoxifying Agents in Feed

Kumar¹,

Sinha²,

Meshram³

et al. 2018

Int.J.Curr.Microbiol.App.Sci

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Rapid analysis of bacterial contamination of tap water using isothermal calorimetry

Cited by 26 publications

References 39 publications

Comparative analysis of Staphylococcus aureus and Escherichia coli microcalorimetric growth

Comparative analysis of Staphylococcus aureus and Escherichia coli microcalorimetric growth

An alternative sterility assessment for parenteral drug products using isothermal microcalorimetry

Myco-toxins Monitoring Device and their Management Strategies through Detoxifying Agents in Feed

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