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How does the BactiQuant® method compare to traditional plate counts ?
BactiQuant® differs from culture-dependent methods in two significant areas. The result is not dependent on whether the bacteria can grow on certain media, and the analysis result includes suspended bacteria as well as particle precipitated bacteria. Compared to direct counts BactiQuant® has the advantage that the result is not affected by the individual technician’s subjectivity.
Can the BactiQuant® be calibrated to traditional plate counts ?
In Denmark BactiQuant® has been calibrated to the international Standard method for plate counts in drinking water; DS/EN ISO 6222.
How does the BactiQuant® method differ from ATP methods ?
ATP is the high energy molecule in living cells that stores the energy that is needed for essentially all energy requiring processes in cells. ATP is present in all animal, plants, bacteria yeast and mold cells and detection of ATP indicates the presence of contamination by any of these sources. The ATP method has been used for decades as a general rapid test for hygiene. There are some limitations to the use of the ATP method for quantifying bacterial presence in water systems. The most important will be discussed below. Interpretation of ATP results are complicated by the existence of extra cellular ATP. In water samples high concentrations of extra cellular ATP can often be detected. In order to measure the relevant ATP it is necessary to open the bacterial cell and extract the cell bound ATP. Cell bound ATP is then estimated by subtracting extracellular ATP from the total ATP. Opening of the cells and measurement of ATP is a complex chemical process. Furthermore, the ATP method is complicated by the use of an enzyme from the firefly. This enzyme is not a natural constituent of environmental samples, such as water samples. The complex chemistry of the ATP method makes the assay less robust and more prone to variation in analysis results, depending on which ATP method is utilised. The BactiQuant® measures the activity of a naturally occurring enzyme in bacteria. The method is based on a simple chemistry which does not require opening of the bacterial cells.
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