a lactic acid-forming Firmicute bacteria that can cause milk to coagulate  and may play a role in food spoilage of highly acidic, tomato-based products.  It is often used as probiotic in veterinary applications, especially in pigs, cattle, poultry, and shrimp. There is evidence that B. coagulans may help humans to improve vaginal flora, reduce abdominal pain and bloating and increase immune response to viral challenges. It might be even beneficial in preventing cancer. Spore-forming strains of B. coagulans strains are used in some countries as probiotics for patients on antibiotics. 
Commercial probiotics with this bacteria include Ganeden BC30 (added to a variety of functional foods and beverages),  Nutribiome, Thorne Research, Schiff, Solaray and many other brands of probiotics. 

rod-shaped, Gram-positive  Firmicute bacteria naturally found in soil and vegetation.. Bacillus subtilis is a notable food spoiler, causing ropiness in bread and related food. It is known for its ability to form a small, tough, protective and metabolically dormant endospore.

Bacillus subtilis is currently used for oral bacteriotherapy and bacterioprophylaxis of gastrointestinal disorders (mostly as a direct result of antibiotic treatment), many of which lead to diarrhea, as an oral probiotic. Commercial B. subtilis probiotic preparations include Enterogermina and Biosubtyl. 

Ingestion of significant quantities of B. subtilis is thought to restore the normal microbial flora following extensive antibiotic use or illness (see this 1994 review). Probiotic preparations of B. subtilis are sold commercially in most European countries, although little is understood about how these bacteria exert their therapeutic benefit. B. subtilis is a gram-positive, nonpathogenic, spore-forming organism normally found in the soil, and the robustness of spores is thought to enable passage across the gastric barrier, where a proportion of spores germinate in the small intestine and populate, albeit briefly, the intestinal tract

A 1999 study found that two commercial preparations of probiotic bacteria purported to contain B. subtilis contain instead Bacillus species that are closely (Biosubtyl) and distantly (Enterogermina) related toB. subtilis. This finding is medically important and raises the question of whether any nonpathogenic, gram-positive microorganism can serve as a probiotic agent.

Bifidobacteria is one of the major types (genera) of bacteria, inhibiting the mouth (B. denium), gastrointestinal tract (B. clostridium), and vagina (Bifidobacterium bifidum, B. breve, B. adolescentis, and B. longum) of mammals, including humans. Some strains, especially Bifidobacterium animalis strain DN-173 010 which has long been used in fermented dairy products, show high gastrointestinal survival capacity and exhibit probiotic properties in the colon. Before the 1960s, Bifidobacterium species were collectively referred to as "Lactobacillus bifidus".

Numbers of intestinal bifidobacteria decrease with age, especially  Bifidobacterium bifidum and Bifidobacterium breve, while Bifidobacterium adolescentis might be increasing, in the continuous process of transformation of microbiota.

Some bifidobacteria are used as probiotics to prevent or treat diarrhea and particular bowel infections Bifidobacterium also have anti-tumor qualities. Manipulating the microbiota may modulate cancer immunotherapy.

​gram-positive anaerobic rod-shaped bacterium Bifidebacterium lactis DN 173-010, a proprietary strain of Bifidobacterium - .lactic acid bacteria that normally live in the intestinal tract and can also be found in fermented foods such as cheese and yogurt. 
Bifidus regularis is a marketing name generated by Danone (known in the US as Dannon) for one of the specific bacteria it uses in its “Activia” range of yogurt products.
According to the Federal Trade Commission, Dannon's advertising contained exaggerated health claims before a settlement reached in December 2010. Specifically, the FTC questioned claims that eating a single serving of Activia a day relieves bowel irregularity and that drinking DanActive prevents colds or the flu. 

strains of S. Salivarius bacteria that produce Bacteriocin-Like Inhibitory Substances (lantibiotic bacteriocins).
Streptococcus salivarius K12 was isolated from the saliva of a healthy child and is used to restore good oral bacteria and improve bad breath. History of commercial application dates back to the year of 2001 in New Zealand. It was shown to exhibit antimicrobial activity against Streptococcus pyogenes and various bacterial species incriminated in the etiology of halitosis Streptococcus salivarius is a prominent member of the oral microbiota of “healthy” humans and is closely related to Streptococcus thermophilus. 

Elixa probiotic contains the following 12 species of Bifidobacterium and Lactobacillus (strength: 500 billion CFUs):

• Lactobacillus Acidophilus
• Lactobacillus Plantarum
• Lactobacillus Reuteri
• Lactobacillus Rhamnosus
• Lactobacillus Casei
• Lactobacillus Salivarius
• Lactobacillus Helveticus
• Bifidobacterium Bifidum
• Bifidobacterium Lactis
• Bifidobacterium Longum
• Bifidobacterium Infantis
• Bifidobacterium Breve

anecdotal evidence exists that Elixa is increasing populations of Lactobacilli in the gut and decreases Firmicutes/Bacteroidetes ratio that has been directly related to weight loss (elevated in obese subjects). 

Bacillus coagulans GBI-30, 6086 (GanedenBC30) is a spore-forming probiotic strain that is resistant to extreme temperatures and survives in the gut environment. It is added to many foods, beverages and supplements, functional foods, nutriceuticals, medical food, animal health and personal care products. It is claimed to help support digestive and immune health.   Expected concentration of BC30 in food and drinks is 100 million to 2 billion CFU per serving.

Species of bacteria in the genus Lactobacillus fermenting sugars (including lactose) into lactic acid. Some strains have probiotic characteristics (for example, L. acidophilus NCFM that decreased the incidence of pediatric diarrhea, and L1 that reduced illness-causing strains of E.coli). NCFM, CL1285, and 36YL strains might have protective qualities against  cancer cells. Lactobacillus acidophilus occurs naturally in gastrointestinal tract, mouth, and vagina, and is used in the production of acidophilus-type yogurt (Lactobacillus delbrueckii subsp. bulgaricus).  Fermented soyben products miso and tempeh can also be good sources of Lactobacillus acidophilus.

Strains
Laboratory: 
NCFM (commercially available since the mid 70s: milk, yogurt, toddler formulas),
ATCC 4962, (produces hydrogen peroxide) Scav [IFO 13951, M. Rogosa 210X, NCIB 8690, P.A. Hansen L 917]
ATCC 4356 (origin: human intestine)
ATCC 9224 (sour milk)
CNRZ216 (origin: rat intestine; different fermentation patterns than other L.acidophilus) 
CNRZ218
Human: HA1, HA2, HA3, HM2, HM6
Pig: PA3, PA12, PA19, P18, P47
Chicken: C1, C2, C3, C7, C11

L. acidophilus AS-1    -  Quest International, Rochester, MN 
L. acidophilus DDS-1    -  Capsule supplement, Natren Inc., Westlake Village, CA  
L. acidophilus HP10    -  Northeast Nutraceuticals, S. Boston, MA
L. acidophilus HP100    -  Northeast Nutraceuticals
L. acidophilus HP101    -  Northeast Nutraceuticals
L. acidophilus HP102    -  Northeast Nutraceuticals
L. acidophilus HP103    -  Northeast Nutraceuticals
L. acidophilus HP104    -  Northeast Nutraceuticals
L. acidophilus HP15    -  Northeast Nutraceuticals
L. acidophilus PIM703    -  Chr. Hansen
L. acidophilus SBT2062    -  ​Snow Yogurt + 2, Snow Brand

intestinal probiotic enhancer designed to improve gastrointestinal function. It contains  Fructooligosaccharides (FOS), mannan-oligosaccharides, arabinogalactans and spores of B. coagulans SBC37-01

​The species of Lactobacillus which have been therapeutically used are :

• B. coagulans (formerly L. sporogenes)
• L. acidophilus
• L. plantarum
• L. casei
• L. brevis
• L. delbruckii
• L. lactis