What are the Different Types of Probiotic Bacteria?

Woman celebrating nature and reaching the summit

The human body is made up of trillions of microorganisms and the gut alone containing more than 500 different species. The guts colony of bacteria are effected by the food we eat and are as individual to each of us, as is our fingerprints. Eating a varied nutritious diet that will increase the beneficial bacteria over bad bacteria in the gut. An imbalance can lead to functional bowel disorders such as allergies and coeliac’ s, metabolic conditions such as type 2 diabetes and also mental disorders such as depression.

The bacteria in the gut are responsible for:

  • Converting fibre into short-chain fatty acids
  • Synthesising certain vitamins
  • Supporting the immune system
  • Weight

Probiotics can be found in certain fermented foods such as sauerkraut, kefir, kombucha and yogurts.

Different probiotic strains have been researched to provide health benefits for different conditions. Some strains are more beneficial than others for certain ailments.

Animal studies have found that certain bacterial strains may decrease the amount of fat the gut absorbs, thereby reducing weight and abdominal fat.

There is a strong connection between the brain and gut with more and more research coming out regularly. Research shows that strains have been able to improve symptoms of different types of anxiety, depression, memory, OCD and more.

Other than for digestive support, probiotics strains are mostly hailed for their supportive action on the immune system. Many diseases are a result of inflammation. Inflammation has been shown to be reduced with the help of probiotics, but also showed increase in anti-inflammatory markers in the gut.

Some doctors may even advise individuals to supplement alongside antibiotics to replenish bacteria that can be killed off during the course. If you are considering taking probiotics, it may be useful to speak to your doctor to be sure they are right for you.


Bifidobacterium genus are gram positive, anaerobic and non-spore-forming. As this species typically thrives in the without of oxygen, the environment in the large intestine is ideal.

This genus of bacteria was isolated in 1899 from the faeces of breast-fed infants. Bifidobacterium is the most common genus of bacteria found in the intestines of healthy infants (90%. This percentage is lower in bottle-fed infants which could explain the higher incident of allergies). As Bifidobacterium is able to metabolise milk sugars, it would make sense that it is found in the gut of breast-fed infants.

While infantis, breve, and longum are the largest group of bacteria found in the intestine of infants, this isn’t equally as high in adults and is only 3-6% of adult faecal flora. As Bifido bacteria decline drastically in the aging process, it could explain the amount of gut issues displayed in older people.


Bifidobacterium ferment carbohydrates, and produce lactic acid as the main metabolic end product of fermentation. Bifidobacteria can break down oligosaccharides and complex carbohydrates (simple sugars such as glucose).

The lactic acid generated by Bifido helps to halt the growth of other micro-organisms such as pathogenic bacteria and yeasts. The pathogens can’t survive in an acidic environment, so this helps retain a healthy balance of flora, protects from intruders; helps mineral absorption for the individual, and may help to protect against leaky gut.

Bifidobacteria also produces a large amount of acetic acid which helps to rid the intestines from yeasts and moulds.

Bifidobacterium breve

Breve are gram-positive, rod shaped and typically anaerobic. It is commonly isolated from infants (especially breast fed) and breast milk.

Breve strains can produce short chain fatty acids which promote a healthy gut environment. Breve also contains enzymes that break down starches, sugars (including lactose) and other components of breast milk.

Bifidobacterium longum & Infantis

Bifidobacterium longum is one of the most commonly found species in human faeces and is subdivided into 3 different biotypes – longum, infantis and Suis.

Longum is most suited to the intestines of breast-fed infants, because it appears to thrive best on human milk oligosaccharides (a prebiotic). It also suggested Longum can be very beneficial for babies with a disrupted microbiome, and that a probiotic supplement containing this strain can benefit formula fed infants.

In breast-fed infants Bifidobacteria make up around 90% of their gastrointestinal bacteria. In vitro studies have also found that Bifidobacterium infantis displays anti-inflammatory activity in premature intestinal cells, as well as decreasing intestinal permeability.

Bifidobacterium Lactis

Bifidobacterium lactis are typically gram-positive, anaerobic, rod-shaped bacterium which can be found in the large intestines of most mammals, including humans.

Lactis is often found in food products, as it is more robust, with higher oxygen tolerance than other species of Bifido. Lactis has also been shown to inhibit the toxic effects of wheat protein gliadin (gluten). This species has also shown some efficacy in decreasing Candida albicans.

Lactobacillus strains

Lactobacillus is likely the most recognised and largest group of probiotic. They are generally gram-positive, rod-shaped and non-spore-forming and can survive in both aerobic and anaerobic conditions.

These bacteria are naturally found in the GI tract and derive their energy from fermenting lactose, glucose and other sugars, and converting these to lactate, lactic acid, or alcohol as a metabolic by-product.

Lactobacilli help in controlling intestinal pH levels through the production of these acids, which decrease the intestinal pH (making it more acidic), restricting the growth of many potentially pathogenic and putrefactive bacteria and favouring the growth of further Lactobacilli as they prefer to live in a lower ph. This helps to maintain a balanced intestinal flora, protect from unwanted intruders and protects against leaky gut. This low pH also helps with mineral absorption such as Calcium, Copper, Magnesium and Iron.

Lactobacillus is naturally concentrated in both plants and animals (such as dairy products). This is we should be eating a variety of foods that may help support a wide diversity of gut microflora, which are vital to the health of your digestive system.

Lactobacillus acidophilus

Acidophilus belongs to a group of gram-positive non-sporulating (non-spore-forming), anaerobic, rod-shaped bacterium. These bacteria typically ferment glucose, with the primary end products of the fermentation being lactic acid, acetic acid and H2O2. All of these substances entering their environment make it more acidic and less favourable for the growth of harmful bacteria, which prefer a more alkaline environment.

Acidophilus may help many factors including a decrease in diarrhoea, decreased Candida albicans, prevention of urogential and lowered serum cholesterol levels.

The species is typically found in the intestine, vagina and urinary tract, as it is can adhere to the mucosal cells in these areas.

Because they use sugars as their preferred substrate for fermentation, the gastro-intestinal tract in humans makes a perfect home for acidophilus, as sugars are available there in abundance. Acidophilus breaks down lactose, the primary sugar found in milk and dairy products; this is useful for those who are intolerant to lactose.

Lactobacillus Plantarum

Produced and preserves key nutrients, vitamins and antioxidants, eliminates toxic components from food and protects food from decay.

This species is thought to adapt to stressors better than other members of the Lactobacillus family. It is good at utilising and breaking down a range of carbon sources wherever they are available to it, and this versatility means that the species can be found and isolated from a range of different sources including saliva, the human intestine, dairy products, plant material, and silage!

Lactobacillus reuteri

Reuteri are gram-positive, rod-shaped, and anaerobic microorganisms, and do not produce endospores. Reuteri typically produces carbon dioxide, ethanol, acetate, and lactic acid from glucose fermentation, and these bacteria are also particularly good at making folate and vitamin B12. It also produces reuterin via the fermentation of glycerol. Reuterin is a potent antimicrobial affecting both gram positive and gram negative bacteria, which helps to aid the survival of L. reuteri bacteria by discouraging other species in their environment. It appears to be so effective as an antimicrobial due to the fact that it has been shown to inhibit ribonucleotide reductase, an enzyme crucial for DNA synthesis, which plays an essential role in the growth and multiplication of prokaryotic and eukaryotic cells and viruses.

Reuteri species is therefore known to help inhibit the growth of harmful bacteria, fungi and protozoa in its host, and due to these properties, it is believed to be a promising therapy for helping to alleviate or reduce certain illnesses related to gastrointestinal, urogenital and oral health.

Lactobacillus Rhamnosus

Rhamnosus is gram positive, anaerobic, and rod shaped.

Rhamnosus exist in the human digestive system, but is also particularly important for female intimate health as certain rhamnosus strains are also known to colonise in the vagina.

Lactobacillus Salivarius

Suppresses and eradicates H.pylori in tissue cultures and animcal models by lactic acid secretion.

Lactobacillus paracasei

Paracasei are typically rod shaped, gram-positive and in addition to lactic acid, they can also produce other metabolites such as ethanol/acetic acid and carbon dioxide (CO2), depending on the conditions and what types of sugars are available to them.

Paracasei is able to adapt to different environments. It is found naturally in both the human and animal intestine.

Lactobacillus casei

Casei is gram positive, rod shaped, non-sporulating (non-spore-forming) non-motile, anaerobic bacteria. As with all Lactobacilli, the bacteria within this species produce lactic acid when fermenting sugars in the intestines, which lowers the pH in their environment. Casei stands out because it is able to survive in a wider range of pH levels and temperatures, which means it is more adaptable and can survive in a variety of locations.

Streptococcus Thermophillus

This species is gram-positive and is another lactase producing probiotic. It is acid resistant and is known most for its modulation of the immune system by stimulating the production of macrophages and stimulate epithelial cell regeneration, digestive system and competes against pathogenic bacteria. It produces antibiotic chemicals to prevent infection. Due to its resistance to stomach acid and bile it can effectively fight off bacteria once it reaches the intestines.

2 thoughts on “What are the Different Types of Probiotic Bacteria?

  1. Thanks for the sensible critique. Me and my neighbor were just preparing to do a little research about this. We got a grab a book from our area library but I think I learned more clear from this post. I am very glad to see such great info being shared freely out there.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.