Integrity - Immunity Flashcards
(155 cards)
Where is the microbiome
stomach, dji, colon
what constitutes the microbiome
firmicutes and bacteroidetes (breakdown carbohydrates in gut -fermentation- , in obesity there is a higher number of firmicutes and lower number of bacteriodetes)
changes in gut microbiome in life
antibiotic use in pregnancy, mother’s diet, hospital, length of gestation, mode of delivery, environment, formula or breast, solid food
breast milk
contains oligosaccharides (HMO), babies can’t digest but B . infantis can by releasing SCFAs which also help promote anti-inflammatory molecules and sialic acid for brain development
what is the function of the microbiome
energy biogenesis, protection from pathogens, immune system education, brain function, bile salt metabolism, vitamin production, drug metabilism
energy biogenesis
resistant starch breakdown by microbiome to SCFAs (fermentation). SCFAs are anti-inflammatory and anti-tumor properties and stimulate protein YY (PYY) whihc induces satiety
microbiome protection from pathogenic bacteria
niche competition and nutrient depletion from invading bacteria, SCFAs inhbit virulence gene expression and lower pH to below optimal growth. Microbiota produce bacteriocins that directly kill salmonella, listeria, clostridium
gut-brain axis
stomal nerve connections in central, autonomic and enteral nervous system contriubuts to GI disease and brain disease
bile acid metabolism
bile acids produced from metabolism of cholesterol involved in emulsification of fat. Microbiota produce secondary bile acids that activate cell surface and nuclear hormone receptors whch cause gut inflammation,
altered microbiome diseases
obesity, T2 diabetes mellitus, IBD, colon cancer, asthma
Probiotics
Little evidence of benefit exceot for T2 diabetes where it can lower cholesterol and fasting blood glucose
IBD
t cell. diarrhoea (blood,mucus), tummy pain
ulcerative colitis
affects colon, chron’s affects mouth to anus. treatment -immunosuppression, aminosalicylic acid, glucocoritcoids. andominal pain, diarrhoea, weight loss. ]fewer firmicutes and clostridium, more enterobacteriocace including e.coi
colon cancer
More common in lower SES, blood in stool, aged 50 fit test - colonoscopy. Rfs = obesity, insulin resistance, red and processed meat, in microbiome - fermentation of diet derived proteins to phenols, indole, n-nitroso compounds, secondary bile acids, ammonia. protective = fibre and excercise. In microbiome - scfas
helicobacter (H). pylori
attaches to gastric mucosa, has enzyme urease which breaks down urea to produce ammonia which neutralises gastic acidity, most common bacterial infection in humans. disrupts gastric mucus layer leading to exposure of mucosa to acidic environment which promotes inflammatory immune response. Causes chronic gastritis which can lead to peptic ulceration, increases risk of stomach cancer
peptic ulcer disease
often asymptomatic but can cause bleeding leading to anemia. upper abdominal pain, indigestion, heart burn, can perforate and lead to severe pain. investiagations = urea breath test with carbon 14 urea to detect CO2 in breath, stool anitgen test, endoscopy, biopsy. treatment: proton pump inhibitor (lansoprazole @prazole) which suppress acid secretion. antibiotics 7 day course of amoxicillin and clarithromycin or metronidazole.
clostridioles difficile
causes antibiotic associated colitis. prevention antibiotic stewardhip esp ciprofloxacin (resp and utis), clindamycin (lung, female reproductive tract), cephalosporins (septicaemia, pneumonia, meningitis, ). treat with metronidazole or rancomycin. can be treated with foecal microbiota trasnplantation (FMT) if disease is recurrent
Primary, opportunistic, commensal, obligate, zoonotic, saphrophytlm
primary - cause harm e.g e.coli
opportunistic - only in right circumstances
commensal - live in harmony but can be pathogenic by accident
obligate - depend on disease for transmission e.g tb
zoonotic- transmitted to animals via direct vector or contact with animal products
saphrophytic - environmental, water or soil
how do pathogens enter, spread, and exit the body
enter :mouth, eyes, nose, urogenital openings, wounds, bites
spread: blood, lymph, nerves (HIV,rabies), cerebrospinal fluid
exit: respiratory, urogenital secretions
pathogenisis
exposure, adhesion (colonisation), invasion, infection
how do pathogens evade detection
concealement of antigens, intracellular persistance, concealment by taking host mmebranes or molecules
people who are more susceptible to infectino
diabetes, chronic renal disease, chronic liver disease, COPD, malignancy, immunosuppression (primary -congenital, iatrogenic - chemotherapy,transplants, acquired - HIV)`
straphylococcus aureus
produces coagulase which clots plasma.colonises in anterior nares, axilla, throat, GI tract. gram + ve round, spreads through direct contact with person or object, particles. Skin infection common (cellulitis), blood (catheter), lung (pneumonia). Antibiotics
E.coli
commonest cause of UTI, ingestion of undercooked foods, water, person to person. Can cause scepticiemia
