3. Gastrointestinal Infections Flashcards
The comparison of the morbidity and mortality of gastrointestinal infection with other enteric diseases.
Diarrhea disease: ____ estimated morbidity (thousands/year); ____ estimated mortality (thousands/year)
Amoebiasis: ____ estimated morbidity (thousands/year); ____ estimated mortality (thousands/year)
Schistosomiasis: ____ estimated morbidity (thousands/year); ____ estimated mortality (thousands/year)
Colorectal cancer: ____ estimated mortality (thousands/year)
300,000-500,000
5,000-10,000
1,500
7-10
20,000
600-1,000
500
Main Pathogenic Enterobacteriaceae and Vibrionaceae
E.coli: ____, dysentery, ____ infection
Shigella sp.: ____
Salmonella sp: ____, enteritis, ____ fever
V. cholerae: ____
* Majority of GI infection - \_\_\_\_ * E.coli - most strains are \_\_\_\_ - some strains can cause a variety of diseases
diarrhea urinary tract dysentery diarrhea enteric diarrhea
gram-negative rod
avirulent
Virotypes of Pathogenic E. coli
MEMORIZE/ADD THIS TABLE!
• Some of them cause disease (different virotype, bc they present a different virulence for different diseases) • Difficult to tell commensal and pathogenic bacteria apart - how can we tell them apart? ○ Most common way: use \_\_\_\_ differences - \_\_\_\_ assays to do quick test whether it's normal or virulent
antigenic
immunologic
• Two antigen are used for identificaition of ____ bacteria
• O antiegn - ____ antigen - most external component of oligopolysacc. - very ____ from organism to organism and species to species
○ E.coli - ____ different types of O
• H antigen - ____ protein
• Based on O and H, you can tell the diff E.coli apart
surface
variable
different
flagella
- For second from bottom - ____
* Using antigenic differences can divide them into different strains
O157:H7
• In US, shigella outbreaks happen in ____ - need to ingest large amount of bacteria to manifest disease; but for shigella, you only need to ingest a few ____ (10-20 cells)
• In day care, changing ____ and ____ in same room > a lot of outbreaks in day care centers
• Shigella happens in ____ adult - has something to do with sexual behavior
○ STD
day care center cells diaper eat homosexual
• Salmonella - similar to ____ (cannot tell diff under microscope)
○ ____ homology - 90%
○ ____ pure pathogen (unlike E.coli)
• Normal ____ bacteria in many animals (domestic animals, chicken, cow) > ends up in our kitchen
○ Cross-____ (using same bowls)
• Used as indicator for ____ of food and water supply
• V. Cholerae - develops \_\_\_\_ ○ Earthquake in Haiti, followed by cholera outbreaks > within months millions dead
E. coli DNA 100% flora contamination safety
cholera
Gram stain of vibrio cholerae
• Cholerae bacteria > \_\_\_\_ > \_\_\_\_ rod
gram-negative
curved
Vibrio cholerae
* Curved rod, \_\_\_\_, with a single \_\_\_\_ * Polar?
gram-negative
flagella
Two types of intestinal infection
____ diarrhea
____ diarrhea and ____
• Bacteria are different, but the mechanisms are different • Watery diarrhea ○ Bacteria colonizes the \_\_\_\_ > produce toxin > poisons and makes you have diarrhea § Enterhogenic, \_\_\_\_ ○ No \_\_\_\_ invasion • Bloody diarrhea and dysentery (and mucus) ○ Bacteria colonize surface, and invade the cell > destruction of the tissue > \_\_\_\_ § \_\_\_\_, and some E.coli (hemorhaggic)
watery
bloody
dysentery
small intestine
cholerae
cell
inflammation
shigella
Symptoms of Cholera
- ____
- nausea/vomiting
- ____
- electrolyte imbalance
- ____
- seizures
- ____
- shock• Paradigm for watery diarrhea
• Water/food contaminated with human ____ > after few hours symptoms start with diarrhea (lose gallons of fluid) > dehydration and ____ imbalance
○ Muscle cramps, seizures, coma and shock
• Without any treatment > only takes ____ hours to develop coma/shock
• Death in ____ hours
• Mortality rate - 50/60%
diarrhea
dehydration
muscle cramps
coma
feces
electrolyte
4-12
18
• Colonize small intestine following ingestion of dirty water/food
○ Not easy to do > bacterial surface and surface of intestine are interacting > mutually ____ each other
○ Another problem > SI is being washed by ____ > if bacteria don’t have ____, then the bacteria are flushed away
§ Have to promote themselves
reject
liquids
adherence
• Most common way > have an ____ (factor how bacteria adhere)
• Enteroggo bacteria > ____ > used to adhere to mucosal surface
○ Stat from bacterial surface and interact with ____ on cell membrane
§ Usually a ____ (glycoprotein or glycolipid)
○ Use interaction bt bacterial and human component
• Makes bacteria stay on surface and ____ intestine
adhesin pilli receptor carbohydrate colonize
- Structure of pili
- Two parts: ____ like structure (composed of array of single ____ - pilli), and then the tip (made of diff protein > interact with receptor on human surface; determines what ____ the bacteria can interact with)
fiber
protein
tissue/organ
Virulence factors of v. cholerae and ETEC
- Adhesins
- V. cholerae ____ pilli
- Enterotoxigenic E. coli (ETEC) ____ and ____
- Toxins
- cholera toxin - shares a high degree of homology with ____ of ETEC• Tcp > toxin [???] regulated pilli?
○ Expressed together
○ Interaction with human tissue
○ The receptor in our intestine is unidentified
• ETEC > CFA-I and CFA-II > many types of pilli
○ More important for ____ diarrhea, any bacteria carrying these pilli• After colonization, the second stage > bacteria produces ____ > cause diarrhea
• Cholera toxin
• ETEC - ____ (and heat stable)
○ Similar to ____ toxin, both structurally and functioanlly
- cholera toxin - shares a high degree of homology with ____ of ETEC• Tcp > toxin [???] regulated pilli?
Tcp
CFA-I
CFA-II
heat labile toxin (LT)
watery
toxins
heat labile toxin
cholera
