Determining the Genus of Microbes

If you are looking for a probiotic for a particular issue you may have, you must take into consideration 3 things that designate a probiotic. They are the genus, species and strain of the probiotic. Each one will determine the probiotic you select.

The genus, which is the broadest and simplest classification for bacteria. The first method used to determine the genus is the gram stain. This is where bacteria are stain with either Crystal violet or it is washed away, and then stained with Safranin red. The bacteria stain purple or red which is its designated Gram reaction.

With the Gram stain can also discern the morphology of the bacteria. This is the shape, size and colony structure under the microscope. Most probiotic bacteria are in the shape of cocci, rods, and diplococci. These colonies form into chains and clusters.

Biochemical testing is used to identify the metabolic activity. This measures whether a bacteria will change the color of media from one color to another (e.g.-from green to yellow).

16S rRNA Sequencing uses the small RNA subunit of ribosomes found in bacteria. This can be used to identify and classify microorganisms in the bacteria. This is now the gold-standard for identifying the genus of bacteria.

Example:

Genus in Bold

Lactobacillus acidophilus NCFM

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