Upper GI micro Flashcards
What is it meant by normal flora?
part of the microbiome - the ecological community of commensal, symbiotic, and pathogenic microorganisms that literally share our body space.
Where are Peyer’s patches found? What are they?
small masses of lymphatic tissue found throughout the ileum region of the small intestine.
What are the 4 phyla in the stomach?
Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes
Wgat are some things in the normal flora of the large intestine
Microbe rich, “microbiome” studied here Anaerobes Gram-negative rods Enterococcus – can survive wide range of stressors and enviromental conditions Spirochetes
Define caries?
Infectious disease that causes tooth decay
Pain, tooth loss, spread of infection
what are the risk factors of developing caries
high-sugar diet, poor oral hygiene, reduced amount of saliva, smoking, periodontal disease
Who has the highest prelvance of caries?
children, common worldwild, at least 1 carried filled
What causes demineralization?
fementable sugars + acid producing bacteria
What is Periodontal Disease?
infectious disease destroying supporting structures of teeth- tissues and bone, -(common and mild form gingivitis- just the gums)
How common is gingivitis?
Affects more than 30% of population worldwide
Peridontisis is more severe than gingivitis- what else is peridontitis asscoaited with?
Heart attack
Stroke
Lung disease
Premature birth or having a baby with low birth weight, in women
What is a biofilm made up of?
consist of two or more species of bacterial microcolonies that are enclosed in a glycocalyx(polysacchrides)
What does a biofilm provide the bacteria?
Adherence
Protection from the immune system
Protection from antibiotics
Symbiotic (but also anti-symbiotic) relationships
Local conditions of pH, etc, in a normally inhospitable environment
What microbes are dominate in the mouth?
Anaerobic organisms predominate but also have gram pos lactobacilli and spirochetes. Some bacteria assoacited with pathogenic infections are there but in lower amlounts considered commensals
What groups of microbes play a role in protecting against dental caries and periodontitis
streptococci, they as producing hydrogen peroxide which inhibits the growth of other oral bacteria
S. sanguinis, S. oralis, S. gordonii, and S. mitis – the “mitis group”
Microbes that cause caries are usually located in plaques on tooth surfaces, often in crevices or between teeth are usually gram pos/neg?
postive!
Microbes that cause periodontal disease do their destruction primarily below the gumline – in the subgingival space are gram pos/neg
negative!
The bad strep is hard to identify-why?
that many oral streptococci are naturally transformable and readily exchange DNA with one another- this complicates 16S rRNA analysis
Strep mutans characterics?
gram pos, cocci beads on a string, cat neg, facultative anaerobe, alpha hemo, opotchin resistant
Different bwtn virulence factors and toxins?
Toxins are virulence factors- which enable the microbe to establish itself within a host
What are strep mutans virlence factors
adhesin-like surface-associated proteins (e.g. AgI/II family), extracellular glucosyltransferases (Gtfs)
What are extracellular glucosyltransferases (Gtfs)
constituents of the pellicle and are capable of synthesizing glucans (a type of polysaccharide) in situ from sucrose. Glucans provide additional S. mutans binding sites, as it binds avidly and in large numbers to these polymers
What are the “Keystone pathogens” in periodontal disease
Treponema denticola – a spirochete
Tannerella forsythia – anaerobic, gram negative
Porphyromonas gingivalis – best studied because it can be cultured
Aggregatibacter (formerly Actinobacillus) actinomycetemcomitans is related to the severity of the periodontal disease
Porphyromonas gingivalis characteristics?
gram neg, bacillus, anerobic, assharolytic, black pigmented colonies on blood agar, bacitracin resistant
Highlighted list of peridontal disease?
P. gingivalis, Capnocytophaga gingivalis, Prevotella denticola
How can you prevent periodontal disease?
Less sugar in diet
Brush and floss frequently
Fluoride
Increased Saliva flow – sugar free gum
What does fluoride do?
for remineralization to counteract the effects of demineralization under low pH conditions
Inhibits bacterial glycolysis and pH maintenance enzymes
Is gingivitis reversible?
yes, treatment is the same as prevention
What is mild periodontitis treatmetn?
scaling, root planing, antibiotics-topical, oral if goes to tissues, emperical-combo of amox/metronidazole
what is severe periodontitis treatment?
surgical tx,
What pathogen causes oral thrush
candida
What pathogen causes Hairy leukoplakia
EBV
Who gets hairy leukoplakia?
HIV patients
What pathogens are assocaited with Ludwig’s angina
Bacterial: alpha-hemolytic streptococci, staphylococci and bacteroides groups
Who gets ludwigs angina>
people who a severe tooth infection or peridontal disease
What pathogens cause Diphtheria/
Strep throat
Corynebacterium diphtheriae
Streptococcus pyogenes
What are the symptoms of ludwigs angina?
Breathing difficulty Confusion or other mental changes Fever Neck pain Neck swelling Redness of the neck Weakness, fatigue, excess tiredness
What form of candidis is dangerous?
Esophageal form
Tx candidis
Most commonly a topical treatment: clotrimazole troches and nystatin suspension (swish and swallow).
Unresponsive cases: a systemic antifungal such as fluconazole
Worst case: IV administration of amphotericin B (significant side effects)
If candidias is untreated what can happen?
invasive candidiasis
Where would C.diptheriae be found? Characterics?
gram pos, bacilli, non spore forming, non motile, PSEUDOMEMBRANE!
S. pyogens characterics, where would it be found?
gram pos, cocci, catalase neg, b hemolytic, bacitracin senstive- on the tonsils!
Characteristics of canidad albicans?
fungus, hyphael forms, bacilli, non-spore forming, non motile,
Leukplakia not caused by a virus is thought to be caused by what?
smoking and chewing tobacco – or other irritations
What are the characterics of EBV?
herpesviridae, ds, linear, DNA, enveloped
Whats the difference bwtn thrush and leukoplakia?
leukoplakia cannot be wiped away!
How is h.pylori transmitted?
fecal-oral
What percent is infected with H. pylori?
US: 50% of adults are infected
Third world: virtually all adults infected
Characteristics of H. pylori?
gram neg, flagellated helix shaped rod (spirilli), microaerophilic, catalase and oxidase POS, urease pos,
t percent of those with H. pylori infection get ulcers? cancer?
only 10-20, 1-2% get distal gastric cancer
Its possible that H. pylori disease outcomes may be related to what?
YOUR micrbiome!
inflammation of gastric mucosa is called?
Gastritis
What are the symptoms of gastritis
Gnawing or burning ache in upper abdomen. May become either worse or better with eating
Nausea
Vomiting
A feeling of fullness in your upper abdomen after eating
What is a gastric ulcer?
Open sores that develop on the inside stomach lining.
What are the more common symptoms of the gastric ulcer?
Felt anywhere from navel to breastbone
Worse when stomach is empty
Flare at night
Often temporarily relieved by eating foods that buffer stomach acid
Disappear and then return for a few days or weeks
how does h. pylori evade the immune response ?
Inhibit phagocytic uptake
Inhibit adaptive immune response
Evade killing by reactive oxygen species and nitric oxide
Evade recognition by pattern recognition receptors
H pylori is urease pos, what does that due to the local environment
raises pH- annomia
How does h pylori get through the low PH layer?
flagella!
What does the increase pH allow the bacteria to do?
Swim around!
What are the two best virulence factors of H. pylori?
VacA and CagA
What does VacA do?
Pore forming cytotoxin that allows leakage of Ca+ from epithelial cell
What deos CagA do?
Type 4 secretion system (TFSS) is a needle through which CagA travels into the host cytosol and affects the proliferative activities, adhesion, and cytoskeletal organization of epithelial cells.
How do you diagnosis H. pylori>
Endoscopy + culture
Breath Test
Stool test
Blood test
Tx of H. pylori
Antibiotics will be necessary (often clarithromycin and amoxicillin; the 1,2) to remove H. pylori
Proton pump inhibitor (3rd arm of triple therapy) to aid in the healing of ulcer
Whats the gold standard of diagnosing H. pylori?
endoscopy but its invasive and expenisve, instead use a use a guided biopsy
How is the rapid urease test done>
With a biopsy, sample is put on a plate containing urea and phenol red, if H. pylori is present, it will hydrolize urea to ammonia and produce a red color. Yellow=neg
What does the breath test detect?
radioactive Co2- the patient is given capsule with urea and if they have H.pylori will be converted to ammonia, Good for diagnosis
Good for confirming cure
Requires skilled technician
What does the blood test H. pylori detect?
antibodies, Useful for initial diagnosis only
Not useful for confirming cure
What is a stool antigen test good for regarding H pylori?
Easy
Good for diagnosis
Good for confirming cure
What kind of cancer can H. pylori cause?
MALT and Gastric carcinoma
What kind of cancer is MALT? symptoms? tx?
b cell, Indigestion, heartburn (stomach pain),antbiotics
What kind of cancer is
Gastric carcinoma
Cancer of stomach lining (epithelial cells)
