In my last Blog about the Genus of Probiotics I described how the genus is determined. In this blog I will describe the second part of the probiotic name.

Using the same example as in the last blog, Lactobacillus acidophilus NCFM, the bolded acidophilus is the species name. But how is the species determined.

There are the 4 Criteria:

1             Genetic Criteria

As with the Genus of a Probiotic, the species utilizes 16S rRNA sequencing in bacteria. Detecting similarity of ≥97% suggests that bacteria belong to the same species.

With ANI ≥95% confirms the species identification by 16S rRNA sequencing.

Other genomic tests include Core genome and pan-genome analysis. These further refine species classification.

  • Biochemical and Metabolic Differences

A probiotics ability to ferment different sugars, enzyme production, and antibiotic resistance patterns.

  1. Example: Lactobacillus rhamnosus Lactobacillus casei differ in their ability to metabolize certain sugars.

3             Ecology and Host Association

In some instances, species are where the bacteria live or thrive in unique environments.

  1. Example: Escherichia coli is primarily found in the human gut.

4             Pathogenicity and Functional Traits

Some species are identified based on their impact on health or disease.

  1. Example: Staphylococcus aureus (pathogenic) vs. Staphylococcus epidermidis (commensal).

So, the Genus (from the previous blog), genus was originally determined by gram stain, morphology and biochemical testing. Lately though, genetic testing is used more and more to determine the Genus

Species used biochemical and metabolic differences, ecology and host associations and pathogenicity and functional traits.  However, genetic testing is the gold standard and is more accurate.

#Probiotics   #Strain    #Genetic Determination    #Biochemistry    #Environment