Break up cell clumps
Some bacteria form chains or clumps that a vortex cannot separate. Break them into single cells before you measure.
Does your sample contain bacteria that form chains or clumps? Then break them up into single cells before you measure.
Not sure? Look at your sample under a microscope. Chains are typical of Streptococcus, Lactococcus and Bacillus, and clusters of Staphylococcus.
Your BactoBox® counts a clump as one cell, so a clumped sample reads low and its cell size reads high. Large clumps can also block the flow paths in your setup.
Two methods to start with
No single protocol works for every organism. These two are a reasonable place to begin.
Bead beating
Add 1 mL of 3 mm glass beads to 5 mL of sample. Run for 1 minute at maximum speed in a bead beater, or 3 minutes at maximum speed on a vortex mixer.
Syringe homogenization
Pass 200 µL of sample through a 27G needle 20 times.
Check that it worked
Treat the same sample a little harder and measure again. If cells/mL rises, clumps were still there. If it falls, you are lysing cells, and a lysed cell is not counted. A microscope confirms the clumps are gone.
Find a method for your organism
Other groups may have solved this for your genus already. Search Google Scholar and PubMed® for your genus together with terms such as "flow cytometry", "disaggregation", "single-cell", "dispersant" and "homogenization". Procedures developed for flow cytometry are the ones worth copying, because they are built to give single, non-lysed cells.
Custom method development
Finding a disaggregation procedure for a specific organism is development work rather than a setting you can change. SBT offers it as a paid custom solution. We scope the work with you, develop and test a procedure for your organism, and hand it over.
Contact us to start that conversation.
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