Infectious Diseases to Gastrointestinal Tract

Question 1

What is the digestive system sometimes referred to?

Answer 1

alimentary or gastrointestinal tract

Question 2

What is the major route of microbial invasion?

Answer 2

digestive system

Question 3

What is the main purpose of the digestive system and how is it divided?

Answer 3

provide nutrients to body; divided into upper and lower tracts

Question 4

What are all intestinal surfaces coated with?

Answer 4

mucus: IgA can be found on most surfaces

Question 5

What does saliva contain that helps against infectious diseases?

Answer 5

lysozyme and lactoferrin

Question 6

Why does normal flora not exist in the stomach? What is stomach fluid and bile considered?

Answer 6

because of its extreme acidity. Considered antimicrobials

Question 7

GALT meaning

Answer 7

Gut-associated lymphoid tissue

Question 8

Lactoferrin

Answer 8

bacteriocide/ fungicide: high levels of colostrum

Question 9

What does GALT include?

Answer 9

Tonsils and adenoids in the oral cavity
small areas of lymphoid tissue in the esophagus
Peyer’s patches in the small intestine

Question 10

What is the most common species that colonizes oral cavity?

Answer 10

streptococcal species

Question 11

What limits the number of bacteria on mucus membranes in the normal flora of the mouth?

Answer 11

Host limits the #.

Membrane cells are constantly shedding

Question 12

Why can large numbers of bacteria collect on teeth? what can they form? what is this called

Answer 12

Teeth are non-shedding surface

large numbers of bacteria can collect and for biofilm, masses of bacteria termed dental plaque

Question 13

What are the predominant organisms of the normal flora in the small intestine?

Answer 13

facultative gram negative bacilli, and some streptococci

Question 14

Approximately how many bacteria per gram are found in the large intestine normal flora?

Answer 14

10^11 bacteria per gram

Question 15

What is the high population of bacteria in the large intestine due to?

Answer 15

nutrients in feces

Question 16

What species predominate the normal flora of the large intestine?

Answer 16

escherichia coli and other enterobacterium

Question 17

What is the most common cause of UTI’s in women and why?

Answer 17

fecal matter; bad wiping, important source of opportunisitc infections

Question 18

What is the most common infectious disease of human beings?

Answer 18

dental caries

Question 19

What % of US population over 65 have lost all their teeth?

Answer 19

47%

Question 20

What can be said about the symptoms of dental caries?

What are three?

Answer 20

Carie is usually advanced before symptoms arise

throbbing pain, discoloration of teeth, breaking when chewing

Question 21

What is the most common causative agent for dental caries?

Answer 21

streptococcus mutans (gram positive)

Question 22

What conditions do streptococcus mutans thrive in?

Answer 22

acidic conditions

Question 23

What do strep. mutans do with dietary sugars?

Answer 23

produce lactic acid from sugar metabolism

Question 24

What do strep. mutans do with sucrose?

Answer 24

produce glucans, essential for production of dental caries

Question 25

How does the cariogenic plaque form in a dental carie?

Answer 25

production of glucans bind organisms together and to tooth

Question 26

What causes calcium phosphate in teeth to dissolve? what does that cause?

Answer 26

acidic environment, creates pits and fissures for colonization

Question 27

What are the symptoms of Helicobacter pylori Gastritis? and when do they occur?

Answer 27

belching, vomiting, abdominal pain, tenderness, bleeding, occur when infection is complicated with ulcers or cancer

Question 28

What is the causative agent of Helicobacter pylori Gastritis? what are the features of it?

Answer 28

``` helicobacter pylori (gram - bacteria) short spiral microaerophile multiple polar flagella ```

Question 29

What is particular about Helicobacter pylori and acidity?

Answer 29

they can survive in extreme acidic conditions and they are able to neutralize the environment that they are in

Question 30

How do Helicobacter pylori use their flagella?

Answer 30

corkscrew through mucosal lining, inflammatory response begins

Question 31

How is Helicobacter pylori Gastritis most likely transmitted?

Answer 31

fecal-oral route: maybe flies

Question 32

What % age of the US population is infected with Helicobacter pylori Gastritis? which group is most affected?

Answer 32

20%, almost 80% of those 75 are infected. | lower socioeconomic groups

Question 33

What are some preventions and treatment of Helicobacter pylori Gastritis?

Answer 33

no proven prevention measures infection can usually be eradicated with combined antibiotic treatment Medication is also used to inhibit production of stomach acid

Question 34

What are the symptoms of shigellosis?

Answer 34

dysentery (Diarrhea); headache, vomiting, fever, stiff neck, convulsions, joint pain

Question 35

Who is shigellosis commonly fatal for?

Answer 35

infants in developing countries

Question 36

What are the four species of shigellosis?

Answer 36

S. flexnuri S. boydii S. sonnei S. dysenterriae

Question 37

Pathogenesis of S.dysenteriae

Answer 37

produces potent a-b toxin shiga toxin acts much like cholera toxin toxin associated with fatal hemolytic uremic syndrome

Question 38

What do shiga and cholera toxins cause leading to loss of solutes and thus loss of water? What does the inflammatory response account for?

Answer 38

cause disregulation of cAMP in host cells. inflammatory response accounts for blood

Question 39

What is the general source of transmission of shigellosis?

Answer 39

generally human source; transmitted fecal-oral route

Question 40

What does shigellosis have making it not easily killed by stomach acid?

Answer 40

does not have high infecting dose | as few as 10 organisms

Question 41

What is transmission of shigellosis most often a result of?

Answer 41

overcrowding, also common in day cares and among homosexual men

Question 42

Is there a vaccine available for shigellosis?

Answer 42

no

Question 43

What is the most important treatment for shigellosis?

Answer 43

fluid and electrolyte replacement.

Question 44

What is the drug of choice for shigellosis and what are the newer drugs?

Answer 44

ampicillin is drug of choice, newer penicillins or ciproflaxacin

Question 45

What are the signs and symptoms of clostridium difficile

Answer 45

diarrhea commending in late antibiotic therapy or even after therapy has stopped. severe cases exhibit abdominal cramps, fever and leukocytosis.

Question 46

What does the colon gradually slough off loose, membranelike patches calles..

Answer 46

pseudomembranes

Question 47

What will happen if the condition Clostridium Difficile is not stopped?

Answer 47

perforation of the cecum and death can result

Question 48

What is the causative agent of clostridium difficile?

Answer 48

gram positive endospore forming rod

Question 49

What are the virulent factors of c. difficile?

Answer 49

able to superinfect the large intestine when drugs have disrupted the normal biota produces A and B enterotoxins: cause necrosis in large intestine

Question 50

What is C. difficile now known as?

Answer 50

a condition called psedomembranous colitis: or antibiotic associated colitis

Question 51

What is the major cause of diarrhea in hospitals?

Answer 51

C. difficile | community acquired infection have been on the rise in the past few years

Question 52

What can predispose people to infection?

Answer 52

use of gastric acid inhibitors.

Question 53

What is the treatment of uncomplicated cases of clostridium difficile?

Answer 53

withdrawal of antibiotics and replacement therapy for lost fluids and electrolytes.

Question 54

How are more severe infections c. difficile treated?

Answer 54

treated with antibiotics for several weeks until the intestinal biota returns to normal

Question 55

What are the two types of antibiotics that are used to treat more severe infections of C. difficile and how do they work?

Answer 55

Vancomycin: cell wall synthesis inhibitor for gram + Fidaxomicin: (approved in 2011) nucleic acid synthesis inhibitor especially effective for clostridium