EXAM #1: BACTERIAL INFECTIONS OF THE GI TRACT Flashcards Preview

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Flashcards in EXAM #1: BACTERIAL INFECTIONS OF THE GI TRACT Deck (81)
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1
Q
What are the symptoms of Botulism poisoning?
A
1) Dizziness
2) Dry mouth
3) Blurred vision
4) Abd. sx
5) Progressive paralysis
2
Q
What causes Botulism?
A
Improperly canned (non-acidic food)
3
Q
When do the symptoms of Botulism start?
A
12-36 hours after ingestion
4
Q
Is fever present in Botulinism?
A
No--only ingested toxin, NOT whole pathogen
5
Q
What organism causes Botulinism?
A
C. botulinum
6
Q
List the characteristics of C. botulismsm.
A
Gram positive
Spore forming
Rod-shaped
Anaerobic
7
Q
What kind of toxin is the C. botulinum toxin?
A
A-B Bacterial toxin
8
Q
What is the MOA of the C. Botulinum toxin?
A
1) B portion attaches to receptors on motor nerve endings
2) A portion enters nerve cell
3) Toxin blocks release of ACh
9
Q
What causes Floppy Baby Syndrome?
A
C. Botulinum spore ingestion
10
Q
What are the symptoms of Floppy Baby Syndrome?
A
Constipation followed by generalized paralysis
11
Q
Where are C. botulinum spores and toxins identifiable in Floppy Baby Syndrome?
A
Feces
12
Q
How is Botulsim treated?
A
Antitoxin administration
13
Q
What is a major adverse effect of Botulism antitoxin administration?
A
Serum sickness
14
Q
What are the characteristics of Clostridium difficile?
A
Gram positive
Spore forming
Rod-shaped
Anaerobic
15
Q
What does Clostridium difficile cause?
A
Antibiotic associated pseudomembranous colitis
16
Q
What is the most common cause of nosocomial diarrhea?
A
Clostridium difficile
17
Q
How is Clostridium difficile transmitted?
A
Fecal-oral
18
Q
What antibiotic was the first abx to cause pseudomembranous colitis?
A
Clindamycin
19
Q
What are the most common causes of pseudomembranous colitis today?
A
2nd and 3rd generation cephalosporins (only b/c they are the most frequently used)
20
Q
What are pseudomembranes?
A
white-yellow plaques on the colonic mucosa
21
Q
What is a severe complication of Clostridium difficile infection?
A
Toxic megacolon
22
Q
How do you tell the difference between adverse diarrhea with abx administration vs. Clostridium difficile?
A
Clostridium difficile toxin present in the stool
23
Q
How is Clostridium difficile treated?
A
1) Withdraw antibiotic
2) Oral metronidazole* or vancomycin
3) Fluid replacement

*Preferred
24
Q
What is Shigellosis?
A
Dysentery i.e. bloody diarrhea
25
Q
List the characteristics of Shigella dysenteriae.
A
Gram negative
Rods
Non-lactose fermenting
26
Q
How does Shigella dysenteriae appear on MacConkey agar?
A
Colorless b/c non-lactose fermenting
27
Q
How is Shigella dysenteriae distinguished from Salmonella?
A
1) Do NOT produce H2S
2) Non-glucose fermenting
3) Non-motile
28
Q
What infective dose is required for Shigella dysenteriae infection? How does this compare to Salmonella?
A
Shigella dysenteriae= low

Salmonella= high
29
Q
What type of diarrhea is seen with Shigella dysenteriae?
A
Bloody diarrhea
30
Q
What is the typical symptom progression in Shigella dysenteriae infection?
A
1) Fever, abdominal cramping and diarrhea
- Watery diarrhea at first
- Bloody/ mucousy diarrhea
31
Q
What strain of Shigella causes a much milder disease than Shigella dysenteriae?
A
Shigella sonnei
32
Q
What strain of Shigella is most common in the US?
A
Shigella sonnei
33
Q
What is the drug of choice to treat Shigella dysenteriae?
A
A fluoroquinolone i.e. Ciprofloxacin
34
Q
What is the drug of choice for Shigella dysenteriae in kids?
A
TMP-SMX
35
Q
What drugs are contraindicated in Shigella dysenteriae?
A
Antiperistaltic drugs
36
Q
Why are Fluoroquinolones NOT used in kids?
A
Increased risk of tendinitis and tendon rupture, especially in kids
37
Q
List the different infections caused by Salmonella species.
A
1) Enterocolitis
2) Typhoid fever
3) Septicemia
4) Osteomyelitis
38
Q
List the characteristics of Salmonella.
A
Gram negative rod
Non-lactose ferm.
Produce H2S
39
Q
What antigens are associated with Salmonella?
A
O= LPS
H= Flagella
K= Capsule
40
Q
What is the species of Salmonella most responsible for entercolitis?
A
Salmonella typhimurium
41
Q
What is the important host defense against Salmonella typhimurium ?
A
Gastric acid
42
Q
What does gastrectomy and use of antacids do to the infectious dose of Salmonella typhimurium ?
A
Lowers it
43
Q
What disease is caused by Salmonella typhi?
A
Typhoid Fever
44
Q
Where does Salmonella typhi replicate?
A
Mononuclear phagocytes of the Peyer's Patches
45
Q
After Salmonella typhi enters the GI tract, where does it go?
A
1) Liver
2) Gallbladder
3) Spleen

****Organism likes the gallbladder and can develop a carrier state there*****
46
Q
What is the typical course of Salmonella in a healthy individual?
A
Non-bloody diarrhea that does NOT require medical care
47
Q
What patient populations are at risk of life-threatening Salmonella infection?
A
1) Kids
2) Elderly
48
Q
What are the symptoms of Typhoid Fever?
A
1) Flu-like symptoms
2) Fever/ constipation
3) Bactermeia
4) Rose-spots
49
Q
How is Salmonella Enterocolitis treated?
A
Fluid and electrolyte replacement
50
Q
When are antibiotics indicated in Salmonella Enterocolitis?
A
Only in those at risk for septicemia
51
Q
What drugs should be used to treat Salmonella enteric fever, septicemia, severe enterocolitis?
A
Ceftriaxone or ciprofolaxcin
52
Q
What surgical procedure may be required to abolish the carrier state of Salmonella?
A
Cholecystectomy
53
Q
List the characteristics of E. Coli species.
A
Gram negative rod
Ferments lactose
Facultative anaerobe
54
Q
What is the most common cause of traveler's diarrhea?
A
E. coli
55
Q
What is ETEC?
A
Enterotoxigenic E. Coli
56
Q
What specific strain of E. coli is responsible for traveler's diarrhea?
A
ETEC
57
Q
What is the MOA of the ETEC toxin? What symptom does this toxin cause?
A
ETEC toxin is similar to the cholera toxin and causes a WATERY DIARRHEA
58
Q
What type of diarrhea is seen in ETEC?
A
Non-bloody
59
Q
What is EIEC?
A
Enteroinvasive E. coli
60
Q
What type of diarrhea is seen in EIEC?
A
Blood and pus in feces
61
Q
What is EPEC?
A
Enteropathogenic E. coli
62
Q
What does EPEC cause?
A
Chronic diarrhea in infants
63
Q
What type of diarrhea is seen with EPEC?
A
Watery diarrhea containing mucous
64
Q
What is EHEC?
A
Enterohemorrhagic E. coli
65
Q
What toxins are seen in EHEC?
A
Shiga-Like Toxins 1 and 2 i.e. "SLT-I and SLT-II"
66
Q
What are the symptoms of EHEC infection?
A
Severe disease with bloody diarrhea
67
Q
What is an adverse effect of EHEC infection?
A
HUS
68
Q
What is HUS?
A
Hemolyticuremic Syndrome characterized by:
1) Microangiopathic hemolytic anemia
2) Thrombocytopenia
3) Acute kidney injury

****This is the leading cause of acute renal failure in children worldwide*****
69
Q
What antibiotics should be given to infants with E. coli infection?
A
Gentamycin
Polymyxin
70
Q
How is traveler's diarrhea treated?
A
Bismuth preparations
71
Q
What type of diarrhea is "pathogmneomonic" for Cholera?
A
"Rice-water stool" i.e. severe watery diarrhea
72
Q
Are neutrophils present in the stool of patients with Cholera?
A
NO
73
Q
What are the characteristics of Vibrio cholerae?
A
- Curved gram negative rod
- Tolerates strong alkaline conditions
- Tolerates high salt concentrations
74
Q
What is the MOA of the Cholera toxin?
A
- Heat-labile
- AB subunit protein
- B-binds to receptors on microvilli
- A-activates adenylate cyclase (increases cAMP)
75
Q
How is Cholera treated?
A
Rapid replacement of fluids and electrolytes
76
Q
What are the characteristics of Campylobacter jejuni?
A
- Curved gram negative rod
- Microaerophilic
77
Q
How are severe Campylobacter jejuni infections treated?
A
Erythromycin or ciprofloxacin
78
Q
What disease is caused by H. pylori?
A
Infectious gastritis
79
Q
What are the characteristics of H. pylori?
A
Gram negative
Microaerophilic
Short/ spiral shaped
Polar flagella
80
Q
What allows H. pylori to survive in that acidic environment of the stomach?
A
Urease enzyme that creates an alkaline microenvironment
81
Q
How is H. pylori diagnosed?
A
Urea breath test