Tag Archives: smart incubators

“Too soft, too generous, too nice, and too slow…”

Guidelines for antimicrobial stewardship often include only a cursory mention of the role of the clinical microbiology laboratory, which is a shame, because in my opinion it is one of the key areas where real change to anti-microbial stewardship can be effected. (The other key area is in the writing of sensible narrow spectrum empiric antibiotic policies.)

But we don’t help ourselves…. Speaking generally, I think clinical microbiology laboratories are notoriously bad at antimicrobial stewardship.


Several reasons actually.

Because we are too soft: We often release antimicrobial susceptibilities from the laboratory even when we have no idea what is going on with the patient. I.e. no clinical details have been provided. Therefore we think nothing of releasing a range of antibiotics to the clinician when we don’t actually know what is wrong with the patient, whether they have an infection, and how severe it is.

Antibiotic susceptibilities should not be released unless the laboratory has reasonable evidence that they are required.

Because we are too generous: We are happy to test a whole range of antibiotics (often up to 20 for the one isolate!), “just in case” one of them might need to be used. This range often includes both narrow spectrum and broad spectrum agents. Probably over 95% of all the susceptibilities that we test and report are never utilised.

We need to dramatically reduce the range of antibiotics that we test for and we need to focus our reporting to the narrowest spectrum antibiotics that we can get away with.

Because we are too nice: We have a low threshold for releasing antibiotic susceptibilities on putative pathogens“. By doing this, we have just given the green light for the clinician to classify a putative pathogen as an actual pathogen, and therefore start/continue antibiotics.

If we have isolated a putative pathogen, let’s keep it putative. Report the organism, and ask the clinician to make a clinical assessment, and then to get back to the laboratory if susceptibilities are required.

Because we are too slow: We are certainly quicker than we used to be, thanks to MALDI-TOF, smart incubators, and increasingly rapid PCR platforms, but we need to be quicker still… We need to get rid of self-congratulatory, retrospective infectious serology testing and channel our test budgets into real-time diagnosis with PCR or similar, and on patients who fulfil well defined clinical criteria for testing. We need to get rapid molecular platforms for STDs into Sexual Health clinics so they are not required to prescribe an antibiotic for everybody who walks through the door. We need to increase Influenza and RSV testing during the winter season to try and reduce unnecessary antibiotic prescribing for viral infections.

Not only do we need to be quicker, we also need to be smarter…

The clinical microbiology laboratory doesn’t score very well in the antimicrobial stewardship report card. We need to be bold and innovative to change things for the better.

But it is entirely up to us…


“The Dark Art of Overnight Incubation”

incubatorIf you incubate a plate from 12:00 midday it will look very different the next morning to a plate from the same sample that is incubated from 12:00 midnight. But both plates have had “overnight incubation”.

And the chances are that your microbiology result will be different as well, in terms of what and how much is grown.

We get accredited to the bone these days; a huge amount of time (and money) is spent fulfilling Quality Control requirements. Everything that moves in the lab is now accredited!

….with the exception of incubation times.

If you go into most laboratories (that don’t have smart incubators) and try and work out from the sample audit trail how long each individual plate is incubated for, you will likely be left floundering. Then check the audit trail to see how long the plate has been out of the incubator before it goes back in again…you haven’t got a hope.

Accreditation agencies seem to simply turn a blind eye to this. Probably in the “too difficult” basket.

But it is important, very important. Why accredit everything else and not bother with this?When you move on from primary culture to susceptibility testing, then it gets even more important, with the potential for wrong results, and mis-treated patients.

It is easy for me to say all this of course as I now work in a lab with Kiestra TLA installed. Incubation times are pre-programmed and the plates spend virtually no time out of the incubator. Each plate has an electronic audit trail which is lengthy but accurate. Standardisation is necessarily boring.

“Overnight incubation” is rapidly becoming an outmoded concept for the following reasons:

  • It does not indicate how long the plate is to be incubated for.
  • It does not indicate whether it is the primary or secondary incubation.
  • It infers that nothing can be done with the plate until the next day…

Bettter just to say 1st incubation for x hours, or 2nd incubation for Y hours, if you can.

Now that I know exactly how long my plates have been incubated for, it has made me realise just how ad hoc things were before. I guess that is the good and bad thing about new technology. It highlights, and in a relative way, accentuates, previous flaws in the system…


Regarding “The Art of Clinical Microbiology”, out of the first edition of 200 copies, I have about 80 books left to sell. Checking my spreadsheet, (and in order of popularity), copies are now in New Zealand, Australia, UK, Republic of Ireland, USA, Singapore, India, Germany, Canada, Greece, & Saudi Arabia.


“Silence is Golden…”


The Kiestra TLA system has now been in place for 3 months at my laboratory. A lot of the initial (and inevitable) teething problems have been sorted, routines have been established, and we can now start to fine tune the system to get the most out of it. The difficult period is coming to an end, and we can now start to enjoy the system.

One initiative that has started in the last couple of weeks is having a microbiology scientist in the laboratory overnight, thus forming a 24 hour roster.

The Kiestra TLA system lends itself to 24/7 put-up and reading. With an overnight shift in place, microbiology samples coming in from the hospital can be inoculated and cultured immediately on arrival in the laboratory, as opposed to having to wait until the following morning. The smart incubators also mean that plates will be imaged and be available for reading 24 hours a day, just so long as there is someone there to read them…

Our experience so far is that for the scientists on the “graveyard” shift, with none of the typical daytime distractions, can simply get their head down and “plough” through the reading lists.

Silence is golden!