Bacterial Strains and Gut Microbiota: What They Are and How They Differ from Prebiotics

Carlos Sánchez 6 min. of reading For the Intestinal Flora Leave a comment

The gut microbiota is made up of a wide variety of microorganisms that inhabit our digestive system. These include bacteria, archaea, fungi and viruses, all of which form part of this complex ecosystem.

But what is the relationship between the gut microbiota and bacterial strains? Are they the same thing? What are the differences between bacterial strains and prebiotics? We explain their main characteristics.

What is the gut microbiota?

The gut microbiota, traditionally known as intestinal flora, refers to the collection of microorganisms that inhabit the gastrointestinal tract, particularly the large intestine.

It consists of numerous bacterial species, along with other microorganisms, and its composition can vary considerably between individuals.

Some of the bacterial genera found in the gut microbiota include:

Bacteroides: one of the bacterial genera commonly found in the human gut.
Bifidobacterium: a bacterial genus that includes various species present in the microbiota.
Lactobacillus: the traditional name for a group of bacteria that has since been divided into several genera following taxonomic reclassification.
Faecalibacterium: a bacterial genus found in the gut microbiota of many individuals.

The composition of the microbiota is dynamic and is influenced by various factors, including age, diet, environment and individual characteristics.

What is the relationship between the gut microbiota and the human body?

The gut microbiota forms part of the human digestive ecosystem and interacts with its surrounding environment in numerous ways.

Intestinal microorganisms participate in metabolic processes involving the transformation of dietary components that reach the large intestine.

For example, certain bacteria can ferment substances that have not previously been digested, producing different metabolites.

These interactions are part of the normal physiological functioning of the intestinal ecosystem and represent an important area of scientific research.

It is important to distinguish between the functions of microorganisms that naturally form part of the microbiota and the effects that may be attributed to consuming food supplements containing bacterial strains.

What are bacterial strains?

In the scientific context of probiotics, certain bacterial strains are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.

This is based on the commonly accepted scientific definition of probiotics. However, it does not mean that every live microorganism or food supplement containing bacterial strains has demonstrated beneficial effects.

Preparations containing live microorganisms may include different genera, species and strains. Some of the best-known microorganisms include:

Bacteria traditionally classified within the genus Lactobacillus.
Bacteria belonging to the genus Bifidobacterium.
Certain species of Streptococcus.
Yeasts such as Saccharomyces boulardii.

Each formulation, such as GI Biotics 25 Billion CFU by EssentialSeries, may contain a different combination of microorganisms, concentrations and additional ingredients.

What is the difference between gut microbiota and bacterial strains?

Although both concepts are related to microorganisms, they do not mean the same thing.

Concept	Definition
Gut microbiota	The collection of microorganisms that inhabit the intestine.
Bacterial strains	Specific strains of bacteria, some of which may meet the scientific criteria established for probiotics.
Prebiotics	Substrates selectively utilised by host microorganisms.
Tyndallised microorganisms	Preparations containing microorganisms that have undergone heat treatment to inactivate them.

Therefore, the gut microbiota is an ecosystem of microorganisms, whereas bacterial strains refer to specific types of bacteria that may be present in the microbiota or used in particular formulations.

What are prebiotics?

Prebiotics are substances that can be selectively utilised by certain host microorganisms.

Some compounds found in foods, particularly certain fibres and oligosaccharides, may be classified as prebiotics when they meet the relevant scientific criteria.

Some well-known ingredients include:

Inulin: a type of fructan found in plant-based foods.
Fructooligosaccharides (FOS): carbohydrates made up of short chains of fructose units.
Galactooligosaccharides (GOS): oligosaccharides composed mainly of galactose units.

Not all dietary fibres are considered prebiotics, as this classification requires specific characteristics.

Foods containing inulin and other fructans

Some plant-based foods naturally contain these compounds:

Leeks.
Artichokes.
Onions.
Garlic.
Asparagus.
Chicory root.

The amount and composition of these substances vary depending on the food and how it is prepared.

What are tyndallised microorganisms?

Tyndallised microorganisms are preparations containing microorganisms that have undergone a heat-inactivation process.

Unlike products containing live microorganisms, tyndallised preparations no longer contain viable microorganisms following treatment.

It is therefore important to distinguish between these two types of formulations.

You can find them in: Tyndallised Biotics 50 Billion Units – Full Spectrum by EssentialSeries.

HSN bacterial strains: different strains and formats

At HSN, you can find a range of food supplements formulated with microorganisms, which differ in their species, strains, concentrations and formats.

One of the characteristics used to describe these formulations is the number of Colony Forming Units (CFU), which indicates the concentration of viable microorganisms.

Information about the species and strains used, additional ingredients and directions for use can be found on each product page.

Frequently asked questions about the gut microbiota

Is the gut microbiota the same in everyone?
No. The composition of the gut microbiota differs between individuals and may change over time.
Do all bacterial strain supplements contain the same bacteria?
No. Formulations may contain different species and strains of microorganisms, as well as varying concentrations and additional ingredients.
Are prebiotics live microorganisms?
No. Prebiotics are substrates, whereas bacterial strains are specific types of bacteria that may be included in live microorganism preparations.
What does CFU mean in food supplements?
CFU stands for Colony Forming Units. It is a microbiological unit used to quantify viable microorganisms.
Are tyndallised microorganisms live bacterial strains?
No. Tyndallised preparations contain microorganisms that have been inactivated through heat treatment.

Conclusion

The gut microbiota is a complex ecosystem made up of numerous microorganisms that inhabit our digestive system.

Understanding the differences between gut microbiota, bacterial strains, prebiotics and tyndallised microorganisms helps clarify the terminology used in microbiology and food supplements.

References

Claus, S. P. et al. (2011). Colonization-Induced Host-Gut Microbial Metabolic Interaction. mBio.
Hill, C. et al. (2014). Expert consensus document: The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nature Reviews Gastroenterology & Hepatology.
Gibson, G. R. et al. (2017). Expert consensus document: The International Scientific Association for Probiotics and Prebiotics consensus statement on the definition and scope of prebiotics. Nature Reviews Gastroenterology & Hepatology.

More information about these bacteria:

Protection against influenza –
Find out more about their beneficial use in babies
Read more about the uses of bacterial strains