Microbiome and Disease (Lec. 25) Flashcards
Define eubiosis
the interspecies balance of microbial species within a microbiome (“normal” microbiota; associated with health and healthy body tissues)
Define dysbiosis
Imbalance of microbial species due to a decrease in microbial richness/abundance within a microbiome. Beneficial microbiota and minimized and other harmful microbiota increase.
Define holobiont
A host and its microbes live together and evolve together
Define superinfection
an infection occurring after or on top of an earlier infection or colonization
Define prebiotics
promote growth of healthy microbiota
Define probiotics
live cultures in food that can establish themselves in the gut microbiome (e.g. yogurt and kombucha)
Define synbiotics
a combination of probiotics and prebiotics, is a treatment for necrotizing enterocolitis
Define the term normal microbiota and discuss its establishment and roles
Permanently colonizes the host and does not cause disease under normal conditions. Includes bacteria, archaea, and eukaryotic microbes; trains our immune system; produces vitamins for us; helps us digest food; may even impact our moods and brain function. Found on the skin, in the mouth, pharynx, and upper respiratory system, the stomach and intestines, and the urogenital tract. Develops from birth and depends on mode of delivery and food intake of the baby. Always evolving/changing.
Explain the hygiene hypothesis and the evidence that supports it.
The theory suggesting that modern internalized environments fail to provide necessary exposure to pathogens required to effectively develop an immune system. Supportive evidence: allergies and asthma (lower rates in tribal populations and in children growing up in rural settings); inflammatory bowel disease (possible link of lack of normal microbiota metabolic products leading to chronic inflammatory state).
Contrast normal microbiota and transient microbiota with opportunistic microorganisms.
Normal microbiota: permanently colonizes the host and does not cause disease under normal conditions. Transient microbiota: may be present for days, weeks, or months, and then disappear.
Describe how the human microbiome contributes to IBD
IBD is a chronic inflammation of the gut, and there is lower gut microbiome diversity. There is also a correlation between a Western diet (more red meat, less fiber) and IBD.
Describe how the human microbiome contributes to obesity
It has been shown that gut microbiota from an obese person, if transferred into another organism, makes that other organism more susceptible to obesity. It has also been shown that in the process of digestion in an obese person, more fermentation occurs and end products are higher in methane.
Describe how the human microbiome contributes to Pseudomembranous colitis
overgrowth of C. difficile, which is Gram-positive (can result from the patient being given an antibiotic that decreases Gram-negative microbiota)
Describe how the human microbiome contributes to Necrotizing enterocolitis (NEC)
NEC is a very serious intestinal disease in preemie babies. Babies that don’t develop NEC have a much more rich and well-balanced gut microbiome than babies that do.
Describe how the human microbiome contributes to dental caries
Plaque is a biofilm usually produced by streptococcal species. When certain fermenting species in these biofilms are in contact with plaque for long periods of time, they produce acids and these acids cause tooth decay (dental caries).
Describe how the human microbiome contributes to periodontitis
Inflammation of the gums; microbiota can occupy your gums and pockets of your gums. There is a significant link between poor oral care and cardiovascular disease. When you brush your teeth and your gums bleed, the bacteria can get into your bloodstream and go to your heart and create endocarditis (inflammation of the heart).
Describe how the human microbiome contributes to acnes vulgaris
The organism that causes significant acne is an obligate anaerobic Gram-positive bacillus that is part of the normal microbiome but an overgrowth can clog pores and cause an inflammatory response.
Describe how the human microbiome contributes to fungal vaginitis
Commonly called a yeast infection; the organism is a fungus budding yeast, most commonly Candida albicans, which are normal on your skin, in your digestive system, and in the vaginal tract. But if you’re taking antibiotics, which can cause dysbiosis, then Candida albicans population will increase. It undergoes some morphological changes where it becomes more filamentous and forms a biofilm
State the class of microbe (bacteria, yeast, virus, etc.) and the Gram morphology (as applicable) for C. difficile
Gram-positive bacteria
State the class of microbe (bacteria, yeast, virus, etc.) and the Gram morphology (as applicable) for Lactobacillus species
Gram-positive bacteria
State the class of microbe (bacteria, yeast, virus, etc.) and the Gram morphology (as applicable) for Streptococcus species
Gram-positive bacteria
State the class of microbe (bacteria, yeast, virus, etc.) and the Gram morphology (as applicable) for C. acnes
Gram-positive bacteria
State the class of microbe (bacteria, yeast, virus, etc.) and the Gram morphology (as applicable) for Candida species
yeast
