Beyond the cell count: Adding microbial fingerprints to water monitoring with BactoScore
- 1 day ago
- 4 min read
For many water operators, microbial monitoring starts with one essential question: How many cells are present?
Total Cell Count provides a fast and valuable overview of microbiological water quality. It helps operators follow trends, identify increases and respond when cell concentrations move outside their normal range.
But cell count does not always tell the whole story.
Two water samples can contain the same number of cells while having very different microbial communities. The overall number may look stable, even though the types and proportions of microorganisms in the water have changed.
This is where BactoScore adds another layer of insight.
A microbial fingerprint for every water sample
Every BactoSense measurement captures much more information than the final cell count. Individual cells produce different fluorescence and light-scatter signals, creating a characteristic pattern for each sample.
BactoScore uses this information to create a microbial fingerprint of the water.
Each new fingerprint is compared with a reference measurement or a normal baseline period. The result is presented as a simple score that shows how much the microbial community has changed.
In practical terms, BactoScore helps answer a second important question:
Is the water still microbiologically similar to its normal state?
It does not identify the individual microorganisms present. Confirming specific organisms still requires laboratory analysis. However, BactoScore can show very quickly that something has changed and that further investigation may be needed.
Why microbial community changes matter
A change in the microbial community can be an early sign that conditions in the water system are shifting.
For example, it may indicate:
the entry of water from another source
contamination or intrusion
changing treatment conditions
instability within the system
a loss of normal process control
In some situations, a small intrusion may change the microbial composition without creating a large increase in the total number of cells. The cell count alone might therefore remain within its usual range, while the fingerprint already shows that the water is different.
BactoScore makes this change visible.
This is particularly useful for water sources where cell counts naturally fluctuate. Rainfall, temperature or seasonal conditions can cause the number of cells to rise and fall without necessarily indicating a problem. If the cell count changes but the microbial fingerprint remains stable, this can reassure operators that the water community is still behaving as expected.
If both the cell count and BactoScore change, the event may deserve closer attention.
Two complementary views of water quality
Cell count and BactoScore do not replace one another. They provide two different types of information from the same measurement.
The cell count shows how many cells are present while BactoScore shows how much the microbial community has changed.
Together, they give operators a more complete view of microbiological water quality. One provides the quantitative anchor, while the other helps reveal changes that may otherwise remain hidden.
Both results come from the same BactoSense measurement, with no additional sampling, reagents or waiting time.
A practical example from spring-water monitoring
The value of combining these two indicators can be seen in spring-water monitoring.
At the Swiss utility WWZ, BactoSense has been monitoring four raw-water sources at a spring-water treatment facility. Operators receive both cell-count data and BactoScore results through BactoCloud.
After rainfall, the cell count in the spring water often increases. When BactoScore remains stable at the same time, this indicates that the microbial community has not changed significantly and that the increase may be part of the source’s normal behaviour.
During an event in summer 2025, however, both the cell count and BactoScore changed.
Laboratory analysis later confirmed faecal contamination in the raw water.
The combination of both parameters allowed the utility to recognise immediately that the event was different from the usual fluctuations observed after rainfall.
Turning existing data into an actionable signal
The microbial fingerprint is already present in every BactoSense measurement. BactoScore simply turns this information into a result that operators can monitor and interpret.
BactoScore is available through BactoCloud Pro and does not require new hardware, cartridges or reagents. Users can define alarm thresholds and receive notifications by email, SMS or through an API connected to their control system.
This makes microbial fingerprinting accessible for routine monitoring without the need for programming or specialist data-analysis tools.
Looking beyond the number
Cell counts remain an essential part of fast microbiological water monitoring. But the number of cells is only one part of the picture.
By showing whether the microbial community itself has changed, BactoScore helps operators distinguish normal fluctuations from unusual events and identify potential problems earlier.
The result is a clearer understanding of what is happening in the water, and a stronger basis for deciding when action is needed.
Would you like to explore the science and methodology in more detail?
Download our technical article, “Beyond the cell count: detecting microbial community shifts with BactoScore,” for a deeper explanation of microbial fingerprinting, research developments and the WWZ application.
Frequently Asked Questions
Does BactoScore replace the total cell count?
No. BactoScore complements the total cell count. The cell count shows how many cells are present, while BactoScore shows whether the microbial community has changed compared with its normal fingerprint. Together, they provide a more complete picture of microbiological water quality.
Can BactoScore identify which microorganisms are present?
No. BactoScore detects that the microbial community has changed, but it does not identify individual species. Laboratory analysis is still required to determine exactly which microorganisms are present.
Do I need additional equipment or reagents to use BactoScore?
No. The microbial fingerprint is already contained in every BactoSense measurement. BactoScore is available through BactoCloud Pro and does not require additional hardware, cartridges or reagents.
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