BacTotal

BacTotal is the recommended and default gating setting for BactoBox®

What BacTotal counts towards cells/mL

BacTotal counts every whole bacterial cell in a sample towards cells/mL.

Examples:

• A whole, actively-dividing cell counts towards cells/mL
• A whole cell that has stopped dividing counts towards cells/mL
• A whole cell that no longer forms a colony counts towards cells/mL
• A whole cell that takes up propidium iodide counts towards cells/mL

Which bacterial species?

BacTotal does not distinguish between bacterial species.

E. coli, Bacillus subtilis, S. epidermidis, etc. all count towards cells/mL.

Legacy strain-specific gating

In the past, we offered custom gating settings to for specific bacteria species. While this worked in some use cases, the approach is too brittle for general use. There are simply too many combinations of bacterial species, sample preparation, media types, culture conditions, etc.

Which cell states?

BacTotal does not distinguish between cell states.

Alive, VBNC, inactivated, etc. cells all count towards cells/mL.

The one thing that removes a cell from the cells/mL count is full lysis. Because a cell that has come apart is no longer there.

Bacterium with broken membrane. BacTotal does not count these towards cells/mL.

Bacterium with intact membrane. BacTotal counts these towards cells/mL.

Live cells grow

The best way to know if a culture is alive is to track its growth. A growing cell is an alive cell.

See How do I differentiate dead and alive cells?

Cell state table

Cell state	BacTotal counts it towards cells/mL?
Viable / alive	Yes
VBNC (viable but nonculturable) / inactivated	Yes
Partially broken membrane / partial lysis / permeable membrane	Yes
Fully broken membrane / full lysis	No

See also

• How do I differentiate dead and alive cells?

• Avoid cell lysis

BacTotal design

We designed BacTotal to have good correlation with CFUs for active cultures across bacterial species.

The latest version is BacTotal_v2024-10. When we just write "BacTotal" or "BacTotal-10", this is what we refer to.

When you press Measure, BactoBox® uses the BacTotal gating settings by default.