Infectious Diseases to Gastrointestinal Tract Flashcards

1
Q

What is the digestive system sometimes referred to?

A

alimentary or gastrointestinal tract

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2
Q

What is the major route of microbial invasion?

A

digestive system

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3
Q

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

A

provide nutrients to body; divided into upper and lower tracts

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4
Q

What are all intestinal surfaces coated with?

A

mucus: IgA can be found on most surfaces

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5
Q

What does saliva contain that helps against infectious diseases?

A

lysozyme and lactoferrin

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6
Q

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

A

because of its extreme acidity. Considered antimicrobials

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7
Q

GALT meaning

A

Gut-associated lymphoid tissue

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8
Q

Lactoferrin

A

bacteriocide/ fungicide: high levels of colostrum

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9
Q

What does GALT include?

A

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

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10
Q

What is the most common species that colonizes oral cavity?

A

streptococcal species

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11
Q

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

A

Host limits the #.

Membrane cells are constantly shedding

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12
Q

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

A

Teeth are non-shedding surface

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

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13
Q

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

A

facultative gram negative bacilli, and some streptococci

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14
Q

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

A

10^11 bacteria per gram

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15
Q

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

A

nutrients in feces

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16
Q

What species predominate the normal flora of the large intestine?

A

escherichia coli and other enterobacterium

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17
Q

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

A

fecal matter; bad wiping, important source of opportunisitc infections

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18
Q

What is the most common infectious disease of human beings?

A

dental caries

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19
Q

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

A

47%

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20
Q

What can be said about the symptoms of dental caries?

What are three?

A

Carie is usually advanced before symptoms arise

throbbing pain, discoloration of teeth, breaking when chewing

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21
Q

What is the most common causative agent for dental caries?

A

streptococcus mutans (gram positive)

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22
Q

What conditions do streptococcus mutans thrive in?

A

acidic conditions

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23
Q

What do strep. mutans do with dietary sugars?

A

produce lactic acid from sugar metabolism

24
Q

What do strep. mutans do with sucrose?

A

produce glucans, essential for production of dental caries

25
Q

How does the cariogenic plaque form in a dental carie?

A

production of glucans bind organisms together and to tooth

26
Q

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

A

acidic environment, creates pits and fissures for colonization

27
Q

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

A

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

28
Q

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

A
helicobacter pylori (gram - bacteria) 
short 
spiral 
microaerophile 
multiple polar flagella
29
Q

What is particular about Helicobacter pylori and acidity?

A

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

30
Q

How do Helicobacter pylori use their flagella?

A

corkscrew through mucosal lining, inflammatory response begins

31
Q

How is Helicobacter pylori Gastritis most likely transmitted?

A

fecal-oral route: maybe flies

32
Q

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

A

20%, almost 80% of those 75 are infected.

lower socioeconomic groups

33
Q

What are some preventions and treatment of Helicobacter pylori Gastritis?

A

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

34
Q

What are the symptoms of shigellosis?

A

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

35
Q

Who is shigellosis commonly fatal for?

A

infants in developing countries

36
Q

What are the four species of shigellosis?

A

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

37
Q

Pathogenesis of S.dysenteriae

A

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

38
Q

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

A

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

39
Q

What is the general source of transmission of shigellosis?

A

generally human source; transmitted fecal-oral route

40
Q

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

A

does not have high infecting dose

as few as 10 organisms

41
Q

What is transmission of shigellosis most often a result of?

A

overcrowding, also common in day cares and among homosexual men

42
Q

Is there a vaccine available for shigellosis?

A

no

43
Q

What is the most important treatment for shigellosis?

A

fluid and electrolyte replacement.

44
Q

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

A

ampicillin is drug of choice, newer penicillins or ciproflaxacin

45
Q

What are the signs and symptoms of clostridium difficile

A

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

46
Q

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

A

pseudomembranes

47
Q

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

A

perforation of the cecum and death can result

48
Q

What is the causative agent of clostridium difficile?

A

gram positive endospore forming rod

49
Q

What are the virulent factors of c. difficile?

A

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

50
Q

What is C. difficile now known as?

A

a condition called psedomembranous colitis: or antibiotic associated colitis

51
Q

What is the major cause of diarrhea in hospitals?

A

C. difficile

community acquired infection have been on the rise in the past few years

52
Q

What can predispose people to infection?

A

use of gastric acid inhibitors.

53
Q

What is the treatment of uncomplicated cases of clostridium difficile?

A

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

54
Q

How are more severe infections c. difficile treated?

A

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

55
Q

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

A

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