Probiotics Flashcards
definition of probiotics
live microorganisms which when administered in adequate amounts confer a health benefit to the host
what are abiotics?
Typically consist of probiotic strains that have been inactivated by lysis, heat, or UV irradiation and have demonstrated some effectiveness in downregulating the inflammatory response in intestinal epithelial cells. Ex: sauerkraut
what are prebiotics?
are non-digestible carbohydrates that act as “food” for probiotics. Prebiotics help probiotics grow and remain in your digestive system. Not all non-digestible carbohydrates are prebiotics. All prebiotics must meet specific scientific criteria.
what are symbiotics?
Food ingredients or dietary supplements combining probiotics and prebiotics in a form of synergism
what are the four major categories of microbial populations in the gut?
- autochthonous microbiota
- normal microbiota
- pathogens
- allochthonous microbiota
what are autochthonous microbiota?
populations of microbes that are present in large numbers and permanently colonize the host
what are normal microbiota?
microorganisms that are frequently in the gut, but can vary in number and be sporadically absent
what are pathogens?
microorganisms that are periodically acquired can persist and cause infection or disease
what are allochthonous microbiota?
microbes from another origin that are present temporarily (most probiotics are also allochthonous)
which bacteria are generally found in probiotic formulations?
LAB and Bifidobacteria (normal constituents of the human Gastrointestinal microflora)
…. and … species are generally considered to be beneficial to the health of their human hosts
Lactobacillus and Bifidobacterium
which other microorganisms can be used in probiotic preparations?
yeast saccharomyces boulardii
E. coli Nissle
what are the six criteria for selection of probiotic strains?
- origin of strain (human origin then LAB biochemical activity considered)
- biosafety - generally recognized as safe (Lactobacillus and Bifidobacteria have low pathogenic potential)
- tolerance to acid and bile salts - probiotic strains need tolerance to reach the GIT (specifically the colon) expect if they’re sold in. enteric-coated capsules (E. coli Nissle)
- adhesion to intestinal cells - colonize GIT
- production of Antimicrobial substances - LAB produce lactic acid, hydrogen peroxide, and bacteriocins => inhibitory ro other bacteria
- utilization of prebiotics - relationship between pre and pro. Probiotics should be able to use fruit-oligosaccharides
what are the three major avenues through which probiotic cultures have beneficial activities on the GIT?
- interaction with the immune system
- strengthening the mucosal barrier by encouraging production of protective proteins such as mucins (Dysfunction of the GIT barrier can lead to inflammatory bowel disease)
- exclusion of pathogens - inhibit the attachement of bacterial pathogens to the GIT epithelial cells by physically blocking the receptor sites.
what can probiotics be used for?
- lactose digestion
- weight loss
- resistance to enteric pathogens
- anti-carcinogenic
- antihypertensive
- reduction of ulcers
- reduction of urogenital infections
which probiotic formulation was able to double the lifespan of fruit flies? how?
L. plantarum, L. fermentum, and Bifidobacteria longum along with a prebiotic (Triphala)
The mechanism was through the gut-brain-axis of communication -> therapeutic tool in CVD, age-related chronic diseases, diabetes, obesity, etc
which bacterial strain is used in maintaining remission of Ulcerative colitis (a chronic inflammatory bowel disease)? through which mechanisms (3)?
E. coli Nissle
- Direct antimicrobial effect (bacteriocins)
- Bacterial-epithelial crosstalk
- Immune-modulatory properties
why is there controversy around the probiotic effects of S. thermopiles and L. bulgaricus?
no:
- the two species of yogurt starter are not usually considered probiotics, since they are not known to proliferate in the intestines -> called transient (they do not colonize the GIT)
yes:
- Both species have high 𝜷-galactosidase activities, and eating yogurt improves lactose digestion and eliminates symptoms of lactose intolerance
…….. has been shown to colonize the vagina following oral intake (depletion of yeast and decrease in coliform present)
Lactobacillus rhamnosus GR1
why are probiotics used for agricultural animal products? (3)
- enhancement of animal growth
- weight gain
- reduction in the carriage of human enteric pathogens (reduction in the risk of food borne illness)
newly hatched chicks are generally inoculated with bacteria (a 29 species mixture) and this provides resistance to ….
salmonella
cattle given a probiotic cocktail are also more resistant to …. colonization
E. coli O157:H7
the effects of probiotics are controversial, why is that?
- The effect of probiotics is likely small (smaller than with conventional drugs) and is likely confounded by age, diet, and lifestyle
- Study results vary with the strains used, the population level of the probiotic cells delivered, the health marker targeted, and the number, age, and condition of the subject evaluated (we don’t know what the minimal dosage is, and we don’t know how frequently you would have to consume the organism to get the desired effect)
- What are the biomarkers for a healthy GIT? No one can agree on this.
according to a study conducted in 2018 where the effects, in both humans and mice, of of an 11-species probiotic or an FMT, administered after antibiotic consumption, on the GIT community structure were examined, these were the conclusions made:
probiotic better colonizes after …. treatment in both humans and mice
probiotic delays the return of the ….. and delays the return to a ……
- antibiotic treatment
- indigenous microbiome
- homeostatic mucosal transcriptome
what are the trade offs when you take probiotics after antibiotics (3)?
- The probiotics have a “placeholder” effect for the microbiome
- The use of probiotics lengthens the time of “dysbiosis” after antibiotic treatment
- The FMT improved the rate of return to the indigenous microbiome
what are the regulations around probiotics in Canada?
- Probiotic organisms (there’s a list of acceptable species and subspecies) can be added to food products => Using only organisms on the list ensures safety
- There is a list of approved marketing statements you can make for the organisms on this list
- probiotic foods are generally classified as food, however, if you want to sell a product with an advertised “health” benefit, the product may be classified as a natural health product (NHP) and you have to supply evidence to Health Canada to back up the health claim
what is the microbiome?
The microbiome is composed of a community of microorganisms that live in or on the bodies of humans and animals
why is the community of the microbiome important?
This community is very effective at limiting the progression of some infections, such as Clostridium difficile or Clostridium botulinum
what is bovine mastitis?
a painful infection of the bovine mammary gland that is usually caused by a bacterial infection by one of many mastitis causing microorganisms
how are bovine treated to avoid mastitis?
treated prophylactically with antibiotics each lactation
some of the microorganisms present in bovine milk are probiotics but can also be …
pathogenic
what is an antagonist of staphylococcus aureus (probiotic strain from a healthy cow)?
Aerococcus urinaeequi
