Probiotic Genus, Species and Strain - Why it matters

by Anne Salazar RH (AHG) 

   The scientific research behind probiotics is relatively new. In the past forty-five years, this field has grown from a handful of laboratory studies and clinical ideas into legitimate research. In the early 1990s Abigail Salyers, Ph.D. from the University of Illinois first drew attention to the importance of our diverse intestinal microbiome, the overuse of antibiotics, and how they damage our microbiome (1).  Even though this is a relatively new field still, the research is clear on certain basic principles.  The one we are going to explore in this blog post is the significance of the genus, species, and strains of each probiotic (2). 

Bacteria are categorized by genus, species, and strain. Each probiotic bacteria MUST be identified at this level as each strain carries unique health benefits. Twenty-five years ago when I started utilizing probiotic therapy in my practice, we only had two choices; Lactobacillus acidophilus and Bifidobacterium; the main probiotic strains recognized at the time. Even with those more limited and simple choices, we were able to make a great deal of headway in people’s health. Since then, there has been growing research, creating more specificity around specific strains and their unique benefits (3)..Now we have more specificity in identifying probiotics, not only by Genus, but by Species, and Strains. These specificities help us deal with specific health challenges more therapeutically.

First, we will dive more into the nomenclature. Let’s take the example of  Lactobacillus acidophilus NCFM: 
Lactobacillus (GENUS)
acidophilus (SPECIES)

A genus contains one or more species. Examples of common probiotic genera include Bifidobacterium and Lactobacillus. Species refer to a type of microorganism existing within a genus or family. For example, acidophilus is the name of a species within the Lactobacillus genus. Lastly, a probiotic strain is a genetic variant or subtype of a species. Different probiotic supplements which may both be labeled to contain 5 billion CFUs of Lactobacillus acidophilus may contain completely different strains. This is important! One strain of Lactobacillus acidophilus is not always therapeutically equal to another Lactobacillus acidophilus strain. Strain level matters when you are aiming for a specific therapeutic effect.

     Overall when choosing a probiotic first make sure to look at the label and make sure that it is labeled down to the strain. This is a great indicator of quality. Second, you want to seek out robust, well-researched strains.  It is important to know they are not only well researched, but also clinically tested and documented for quality.  A great example of this is the bacillus strains in our Megaspore Probiotic. This product contains two important and well-studied strains; Bacillus Indicus HU36™ and Bacillus and Subtilis HU58™ among its blend of Bacillus species. This product and these strains have been clinically studied to show their efficacy in helping patients with Irritable Bowel Syndrome (IBS) (3). Studies have shown that certain species of Bacillus spores are capable of quorum sensing. Through quorum sensing, they exert an important regulatory effect on intestinal microbiota resulting in positive effects on both the colon and ileum (4). The results showed that after 34 days of treatment, the impact of Bacillus spores on quality of life indicators was superior to treatment with rifaximin combined with either a nutraceutical agent or a low-FODMAP diet. 

     Any high-quality probiotic manufacturer will be fully transparent with the ingredients. If a strain is not listed, I typically assume that the manufacturer has sourced whatever is cheapest or easiest for them. A company should list strain identifications in the supplement facts panel of every formulation for transparency to ensure consumers that the probiotics have been validated by science.  Because probiotics have taken a lion’s share of the supplement market in recent years, oftentimes generic probiotics are being used.  For instance, I have seen many examples of products that have high amounts of CFU’s in a product specified for urinary tract infections (or some other condition) that doesn't work anywhere near as well as another that has only 10 billion, but 10 billion of the right strains like Jarro-Dophilus Women’s! Again, it's all about the quality of the strains being used.

    Amongst the top quality probiotic manufacturers are Jarrow,  Metagenics, Pure Encapsulations, New Chapter, and Orthomolecular,  all of which we carry at Remedy. Please check out our full probiotic collection here. We know it is of utmost importance to vet our supplements carefully, and this certainly pertains to our probiotics.  When you come in to see us, we can help direct you to the most appropriate choice for whatever situation you are addressing, whether it be maintenance or something more complex. Should you decide to schedule an appointment for a more detailed consultation, we certainly can assist you in getting exactly what you need for any particular challenges you may be experiencing. We look forward to partnering with you for the best possible outcome!

  1. Puebla-Barragan S, Reid G. Forty-five-year evolution of probiotic therapy. Microb Cell. 2019;6(4):184-196. Published 2019 Apr 1. doi:10.15698/mic2019.04.673
  2. Marteau, P., Evidence of probiotic strain specificity makes extrapolation of results impossible from a strain to another, even from the same species. Annals of Gastroenterology & Hepatology, 2011. 2 (1): p. 34-36
  3. Bubnov RV, Babenko LP, Lazarenko LM, Mokrozub VV, Spivak MY. Specific properties of probiotic strains: relevance and benefits for the host. EPMA J. 2018;9(2):205-223. Published 2018 Apr 13. doi:10.1007/s13167-018-0132-z
  4. Catinean A, Neag AM, Nita A, Buzea M, Buzoianu AD. Bacillus spp. Spores-A Promising Treatment Option for Patients with Irritable Bowel Syndrome. Nutrients. 2019;11(9):1968. Published 2019 Aug 21. doi:10.3390/nu11091968
  5. Zhang W., Zhu Y.H., Zhou D., Wu Q., Song D., Dicksved J., Wang J.F. Oral administration of a select mixture of bacillus probiotics affects the gut microbiota and goblet cell function following escherichia coli challenge in newly weaned pigs of genotype muc4 that are supposed to be enterotoxigenic e. coli f4ab/ac receptor negative. Appl. Environ. Microbiol. 2017;83