Gastrointestinal Organisms Flashcards Preview

Micro Exam #2 > Gastrointestinal Organisms > Flashcards

Flashcards in Gastrointestinal Organisms Deck (87)
Loading flashcards...
1

Physical characteristics of enterobacteriaceae?

Facultatively anaerobic
G- Rods

2

Enterobacteriaceae use what type of secretion system?

3

3

What antigens are used to type Enterobacteriaceae.

O, H, K/Vi

4

Biochemical tests for Enterobacteriaceae?

IMViC
Carbohydrate fermentation
Packaged Test Kits

5

What does IMViC stand for?

Indole methyl red Voges-Poskauer citrate

6

How are carbohydrate fermentations occur?

Use MacConkey's Agar (Lactose)
Lac+ are coliforms

7

Name for packaged test kits for Enterobacteriaceae?

Enterotube

8

Three most common causes of foodbourne outbreaks?

Salmonella
Campylobacter
Shigella

9

Relationship of Enterobacteriaceae to endocrine system

Gut bacteria can respond to stress-induced neuroendocrine hormone levels

10

How do bacteria avoid immune response?

Subvert response to avoid detection

11

How can E. Coli be detected on agar?

Copious acid production detected by green metallic sheen on EMB agar

12

Three general clinical syndromes that come from E. Coli

Enteric/Diarrheal Disease
Urinary Tract Infections
Sepsis/Meningitis

13

Most common extraintestinal E. Coli infections?

UTI via UPEC

14

Two ways that E. coli may lead to UTI

Acquire from proximity of anus to urethral meatus
From increased sexual activity (honeymoon cystitis)

15

UPEC is associated with the __ Pilus

P

16

What does EPEC stand for?
What does it do?

Enteropathogenic
Intimin attached protein, bundle formed pili
Efface small intestine microvilli and inhibit water uptake

17

Medical effects of EPEC?
Who gets it?

Watery, self-limiting diarrhea
Esp. Young Children

18

What does ETEC stand for? Nickname?
Medical side effects?

Enterotoxigenic. "Traveler's Diarrhea"
Watery diarrhea, increased gut motility, ab cramps

19

ETEC is associated with what pili?

CFA adhesion pili for brush-border membrane

20

What toxins are produced by ETEC?

2 LT Toxins (LT1 like cholera, higher cAMP)
2 ST toxins (activates cGMP)

21

What does EHEC stand for?
Medical side effects?

Enterohemorrhagic
Bloody diarrhea without fever
Hemolytic-Uremic Syndrome

22

How does EHEC mediate medical effects?

Verotoxin (Shiga-like) -- AB toxin protein synthesis inbititor

23

What is Hemolytic-Uremic Syndrome?
Treatment?

Uremia and organ failure due to glomerular damage
NO anti-biotics -- they induce stx gene

24

What is EIEC?
Medical effects?

Enteroinvasive
Bloody fever with fever

25

EIEC is Indistinguishable from...

Shigella dysenteriae type I

26

Factors produced by EIEC?

Invasive colonization factors

27

What is EAEC?
Medical Effects?

Enteroaggregative
Noninflamatory pediatric diarrhea caused by biofilm development

28

E. coli K1 is a major cause of...

neonatal meningitis

29

Why is E. coli K1 not a good antibody target?

Molecular mimic of host NCAM receptors

30

Who is E. coli K1 especially dangerous to?

low birthweight infants

31

Salmonella grows on what medium?

Selective media with bile salts (deoxycholate)

32

How is salmonella classified?

By serotype (O, H, Vi(K))

33

All salmonella belong to what species?

S. enterica

34

It is important to distinguish what two categories of salmonella enterica?

S. typhi and paratyphi vs. all others

35

Three types of disease caused by salmonella enterica?

Typhoid Fever
Bacteremia/Septicemia
Enterocolitis/Gastroenteritis

36

Typhoid Fever is cause by what forms of salmonella?

S. Typhi or Paratyphi

37

Medical effects of Typhoid Fever?

Invasive disease - reaches bloodstream through mucosa
Disseminates via macrophage to spleen, liver, GB
Death from intestinal hemorrhage

38

Who gets bacteremia/septicemia from Salmonella?

Immunocompromised Patients

39

Medical effects of salmonella enterocolitis/gastroenteritis?

Nausea, Vomiting, Diarrhea, Fever Common
May colonize GB and shed for weeks

40

In what food products is Salmonella enterocolitis/gastroenteritis spread?

Eggs and Poultry Products

41

Four ways in which salmonella enterocolitis/gastroenteritis is spread?

Fecally contaminated water
Endemic in Eggs/Poultry
Crops fertilized by excreta
From Pets

42

Describe pathogenesis of salmonella.

Binds brush border to invade gut epithelil cells
Invade deep tissues/bloodstream
Produce cytotoxic enterotoxin

43

Type of toxin? Effect of components?

A2B5
A1 -- ADP-ribosylates G-protein
A2 -- damages DNA and halts cell replication

44

Shigella can also grow in _____ by ______

Bile
Efflux pumps and DNA repair
Uses Phospholipids as a C-source

45

Shigella grows on ____ agar

S-S

46

Clinical presentation of shigella?

Onset with Acute Watery Diarrhea
2 days later - blood and mucus into stool
Subsides in about a week, but lethal dehydration

47

How is Shigella spread?

Infection via fecal-oral route

48

Shigella is most common in what population?

Children

49

How is Shigella spread?

4 Fs
Food, Fingers, Feces, Flies

50

Explain the pathogenesis of shigella.

- Phagocytosed and transmitted through M cells
- Engulfed by macrophages in lamina propria
- Lyse phagolysosome and replicate in cyto
- Macro apop. -- release IL1 and cytos that make junctions permeable
- Induces basal membrane phagocytosis

51

How does shigella spread?

Actin tails

52

How does shigella secrete invasion factors?

Type III secretions

53

How does Shiga enterotoxin kill?

Disruption of protein synthesis

54

Unique staining seen in yersinia?

Bipolar staining (Wright-Giemsa, Wayson's)

55

How does Yersnia bind?

YadA

56

Yersnia uses what secretion system?
What antigens allow intracellular growth?

Type III
V and W antigens

57

Yersnia pestis is most commonly known as...

plague

58

Three types of yersnia pestis?

Bubonic
Septicemic
Pneumonic

59

Symptoms of Bubonic yersnia pestis?

1-8 day incubation
Malaise, headache, vomiting
Painful Buboes in groin and other lymph nodes

60

What are buboes full of?
What diseases with buboes must yersnia be distinguished from?

Bacteria and Pus
Tularemia, Pasturella

61

Describe septicemic yersnia pestis

Primary or secondary to bubonic
Sepsis, Purpura, DIC, Necrosis

62

Describe pneumonic yersnia pestis?

Primary or Secondary
Primary form inhalation, secondary from intravascular dissemination
Hemoptysis, bilateral alveolar involvement

63

Outlook for pneumonic yersnia pestis

Virtually 100% fatal within 24 hours

64

How is yersnia pestis spread?

Zoonosis
Typically spread by vector (rat flea)
Reservoirs are Deermice and ground squirrels

65

How does yersnia pestis effect fleas?

Toxin blocks flea's gut, forms blood clot
When flea bites again, clot is regurgitated into host

66

Aside from natural transmission, yersnia pestis can be seen as...

A Warfare Agent

67

Pathogenesis of yersnia pestis?

- Type III Secretory System injects toxins
- Inhibits MAP kinase signalling pathway (YopJ)
- No cytokine production, no cell replication
- Inhibits Phagocytosis (YopE)
- Inhibits Platelet Aggregation (YopM)

68

How is yersnia pestis controlled?

Insectiside to kill fleas
Vaccine that must be boosted every 6-12 months

69

How do you treat a yersnia patient treated?

Oral tetracycline for exposed and asymptomatic
I.M. Streptomycin once symptoms

Pneumonic plague treatment is rarely successful

70

Symptoms with Y. enterocolitica

-- Enterocolitis with intestinal abscess -- bloody diarrhea, abdominal cramps, fever
-- Mesenteric adenitis

71

Reservoirs for Y. enterocolitica?

Cattles, Hogs

72

How is Y. enterocolitica spread?

Feces, Contaminated drinking water/milk

73

How are Y. enterocolitica and Y. pseudotuberculosis treated?

Ampicillin
Ceph III, SxT

74

Describe klebsiella pneumonia medical effects.

Small Percent of Pneumonias
Extensively hemorrhagic and necrotizing (currant jelly sputum)

75

Treatment success of klebsiella pneumonia?

50-100% fatal

76

Describe the pathogenesis of klebsiella granulomatis

Granuloma inguinale
Mimics syphilis

77

Describe sores in klebsiella granulomatis.

Painless anal or genital sores
Gradually progressive lesions destroy large areas of tissue

78

How is proteus mirabilis seen on agar?

Swarming motility

79

Proteus mirabilis is associated with what condition?

UTI

80

Proteus miribilis causes what condition? How?

Bladder Stones
Urease production

81

How is Serratia marcescens usually acquired?
Common symptoms?

Opportunistic Infection
Pneumonia, Bacteremia, Endocarditis

82

How are enterobacteria usually treated, generally?

Isolate and clean sources
Ampicillin, Cephalosporins, Quinolines, Sulfa

83

For a uncomplicated UTI, Don't use_______.
1st choice --
2nd choice --

Don't -- Flouroquinolone
1st -- Bactrim (SxT)
2nd -- Fosfomycin

84

Why don't you want to use f'quinolones for UTI?

It mimics a quorom sensing signal, can lead to film formation

85

Typically you would treat Traveller's Diarrhea with ____
You would treat campylobacter with _____

Rifaximin
Azithromycin

86

There has recently been increased appreciation for the importance of restoring normal _______ in GI disorders

Mucus Production

87

Action of MUC2

Subdues dendritic cell inflammatory response via Treg activation