B. spizizenii swarming nightmare on in-house TSA.
Hey everyone, looking for some troubleshooting advice or sanity checks from fellow micro nerds.
We are consistently getting swarming motility with Bacillus spizizenii (<100 CFU / 0.1 mL) on our in-house manufactured Tryptic Soy Agar (TSA) plates.
We are seeing this happen on both spread plates and pour plates. In a typical 4-plate set, they are all the same organism, but the leftmost plate completely loses control and swarms across the surface.
Info to rule out the usual suspects:
Moisture: The plates do not have excess condensation or visible droplets.
Srain: We are locked into this specific strain for regulatory/testing requirements.
Occurancss: This is happening across multiple scientists, different media batches, and different organism sources (both commercially purchased vials and our own frozen cryovials).
Any tweaks or recommendations would be appreciated!