Tips for Microbiology Scientists working on Bacteriology Benches. Part III

 This is the last part of this “Tips for Microbiology Scientists” mini-series.


1) Don’t “over-analyse” anaerobes…

I am not a big fan of identifying all anaerobes isolated, and in particular from superficial sites, where in many cases anaerobic culture should not even be undertaken. Whether the clinician includes anaerobic cover when treating the patient should depend much more on the clinical presentation and the site of infection, as opposed to any information the laboratory provides. Due to the difficulty in culturing anaerobes, a negative result from the laboratory should generally not be used “per se” by the clinician to cease anaerobic treatment.

If mixed anaerobes are present then it is usually pefectly acceptable to report as mixed anaerobes. Identifying each one individually is unlikely to be of benfit to the patient.

In sterile sites, then indeed it may be worthwhile spending time fully identifying anaerobes, particularly when they are a pure single isolate. Some anaerobes can give rise to very particular clinical scenarios, eg Fusobacterium necrophorum giving rise to Lemierre’s syndrome.


2) Think carefully about what organisms you perform susceptibilities on.

There is a lot of “just in case” antimicrobial susceptibility testing that goes on in microbiology laboratories. Ie doing susceptibilities on an organism “just in case” it is the pathogen, and then unnecessarily testing a large range of antimicrobials, “just in case” one of them might be used by the clinician. The third problem in this area is testing where the result is highly predictable; eg, testing beta-haemolytic streptococci against beta-lactams.

My advice is to only perform susceptibilities when:

i)  There is a significant chance that the organism is pathogenic,  and

ii)  The outcome of the susceptibility test is unpredictable.


If susceptibility testing needs to be performed, then only test a limited range of antimicrobials, ie the ones that are the most effective and most likely to be used.


3) Visit other laboratories.

If you spend all your time in just one laboratory, you are likely to start to believe that your laboratory’s “way” is the only way to do things. I think it is very important, regardless of whether you are a trainee or qualified, junior or senior, to spend time in other laboratories, observing or preferably working. In this way, you can find out different approaches to different problems that your laboratory faces, which you can then propose for your own laboratory. If you work in a diagnostic lab, then it is very important to visit referral labs that may be utilised by your laboratory for typing or identification of difficult organisms. This allows you to gain a better understanding of what happens to the sample or isolate when it leaves your lab.


4) Take note of Interesting Cases.

Every laboratory has its’ “bread and butter”, stuff you will see lots of every day. You will know this type of work inside out. However when you do come across something that is unusual and that you might only encounter on that bench once a year or less, then it is worthwhile considering writing the case up for publication in either a scientific or medical journal, or presenting it at a conference. I think it is important to stress here that I am not really interested in organisms that are so abstract that you are likely never to encounter them again, but ones that you may expect to see in your lab once every year or two, so that by writing it up, it is likely to benefit colleagues for future diagnosis and management. For example a Listeria monocytogenes bacteraemia in an immunocompetent individual, an Erysopelothrix wound infection, or a carbapenemase producer in an area where these are not endemic.


5) Be meticulous.

This is a tricky one for me. I am not a naturally meticulous person so I need to be “conciously” meticulous when needed..  However it is an important microbiology skill to have whilst working on the benches, in order to obtain the correct result and secondly to avoid contamination of both the sample and yourself. Because being meticulous can be both tedious and time consuming, it is important to value the importance of meticulousness and also to know why it is important. Some scientists are naturally meticulous, some need to learn how to be so.


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