I'm taking an introductory course to microbiology and immunology, and i have been required to memorise the following microorganisms of the normal flora.

I'm trying to understand before I memorise, and I need your kind help because no textbook or any resource on google had helped me. I am trying to link the etymology and/or characteristics of the microorganism to its anatomical locale, for example: Heliobacter pylori --> helical bacteria, pylorus region of the stomach, or enterococci --> Entero = small intestine, cocci = circular. Some can be found out via a simple google search but the others cannot, can you help me link/understand it? It doesn't have to be anything so jargonic, just clever ways to facilitate memorisation, for example: lactobacilli --> lacto --> lactic acid --> acidic environment of the vagina and bacillus = rod shaped.

Many many many thanks in advance!

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    $\begingroup$ While the name of a microorganism sometimes reflects its shape, that is not always true. Additionally, the name doesn't necessarily reflect its location in the body. $\endgroup$
    – MattDMo
    Commented Oct 18, 2022 at 18:39
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    $\begingroup$ There isn't any clever way to memorize where (everything/whatever) lives, e.g the ubiquitous Candida albicans which basically means white white. Sometimes it's just the hard work of memorizing that gets you through, if that's what you're required to do. $\endgroup$ Commented Oct 18, 2022 at 19:15

1 Answer 1


As mentioned in the comments to the question, binomial names for species are odd ones and don't necessarily relate to anything to do with either common location or a function of the species. However, a lot of the common bacteria were named fairly early on in the process of classifying species at a time when it was fashionable to name them based on a function or a characteristic of the species, much in the manner that Carl Linne did, when he set up the binomial system.

Here's my table of the meanings of the names for the in the list above:

First part definition second part definition
Strepto twisted chain coccus ball
Haemo blood philus loving
Neisseria after Albert Neisser
Candida white
Actino ray (of light) myces fungus
Staphylo bunch of grapes coccus ball
Coryne club shaped bacterium bacterium
Propioni synthesizes propionic acid bacterium bacterium
Entero relating to the intestine bacteriaceae family of bacteria
Entero as above cocci ball
Bacter representing bacterium oides like
Bifido divided in two bacterium bacteria
Clostrid spindle shaped ium suffix
Pepto cook streptococcus see strepto...
Lacto milk bacilli rod shaped
Myco related to fungi bacterium bacteria

As you can see the names sometimes make sense in an immediate manner (e.g. Streptococcus = "twisted chain of balls" and Staphylococcus = "balls in a shape like a bunch of grapes"), but don't always - for example Bacteroides means "bacterium that is representative of bacteria" - which only makes sense if you know that this is probably the most abundant species found in the gut. Also note that for Actinomyces; at the time it was named it was thought to be a fungus - hence the "myces" part. The colonies are fuzzy, like a fungus and form corrugations that, with a bit of imagination, look like rays/beams - hence the "Actino" part; so you kind of need to also know a little of the history to understand some of the names.

As far as I know there is no system from the names to work out the location of the organisms in terms of their names, the closest you might come is to know whether they are anaerobes or aerobes, and that will give you at least a hint of their location(s). However, this won't work for all species, and some are not bacteria, but yeasts, which are eukaryotic rather than prokaryotic.

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    $\begingroup$ this is so beautiful, I can't thank you enough! highly appreciated! $\endgroup$
    – Doe Pual
    Commented Oct 19, 2022 at 10:02

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