“The Art of Interpretation”


At the moment I would estimate that 5% of agar plates worldwide are read by the examination of a digital image, as opposed to someone holding the plate in their hand.

In 10-15 years I predict this percentage will be closer to 50%…

And currently, the vast majority of agar plates are still analysed manually, by a scientist examining the colonies present on the cultured agar plate. 

This also is going to change dramatically over the next 10-15 years…

The process of automated plate interpretation has started. Some automated systems have software in place which can already do the following:

  • Interpret negative/no growth plates, by comparing with a negative template.
  • Interpret chromogenic plates, looking for colonies with a specific colour.
  • Measure and interpret susceptibility zone sizes to antimicrobials.

But this is a science just in its infancy, and I suspect the software will soon be able to do the following:

  • Triage and quantify different colony types on a plate, based on size, colour, edge contour, level of haemolysis. This will then allow Maldi-tof analysis on different colony types.
  • Will be able to assess if the plate growth is sufficient for reading, as opposed to waiting for a pre-programmed time period.

I find it interesting, and somewhat surprising, that a lot of microbiology laboratories are concentrating on “front end” automation ( inoculation and plate spreading) at the moment.

For me, it’s the “back end” which is really going to progress and change over the next decade. Automated colony pickers, combined with plate interpretation software as described above is going to absolutely revolutionise traditional plate reading as we know it…

It is a very exciting area, and plate interpretation software will undoubtedly become very powerful. The great unknown however, is how long culture based microbiology can survive the ever increasing sophistication of molecular diagnosis.

So in summary, by 2030 I think we will be using a lot less agar plates than we do today. But I do think we will still be setting up at least some. However, of those agar plates that are set up, I think at least 50% of them will never be seen by a scientist…


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