Chapter 20: Infectious Diseases Affecting the Gastrointestinal Tract Flashcards
(50 cards)
1
Q
GI Tract Defenses
A
- intestinal surfaces coated with layer of mucus
- IgA found on most surfaces
- peristalsis
- saliva
- lysozyme and lactoferrin
- stomach acid
- bile
- appendix
- GALT
2
Q
GALT
A
- tonsils and adenoids in the oral cavity and pharynx
- small areas of lymphoid tissue in the esophagus
3
Q
How does E. coli assist with digestion?
A
Synthesizes vitamin K
4
Q
Which of the following types of organisms are not considered normal biota of the gastrointestinal system?
A.bacteria
B.archaea
C.fungi
D.protozoa
E.None of the choices is correct.
A
B. archaea
5
Q
Causative agents of chronic diarrhea
A
- E. coli
- Cyclospora
- Giardia
- Entamoeba
6
Q
Causative agents of food poisoning
A
- Staphylococcus aureus
- Bacillus cereus
- Clostridium perfringens
7
Q
Causative agents of dental carries and periodontitis
A
- Streptococcus mutans
- Scardovia wiggsiae
8
Q
Causative agent of mumps
A
Paramyxovirus
9
Q
Causative agent of Salmonella
A
- S. enteritica
- other bacteria may cause also
10
Q
Properties of Salmonella
A
- ferment glucose; Motile
- can survive outside the host in hospitable environments, fresh water and freezing temperatures
- resistant to chemicals
- Most strains come from animals
- Salmonella are normal intestinal biota in cattle, poultry, rodents, and reptiles
11
Q
Signs and Symptoms of Salmonella
A
- Severe forms of salmonellosis can include
- elevated body temperatures
- septicemia
- Milder forms of salmonellosis
- Vomiting
- diarrhea
- mucosal irritation
- blood can appear in the stool
- death is infrequent except in debilitated
12
Q
Illnesses caused by salmonella
A
- Typhoid fever
- caused by the typhi variant. Salmonella typhi infects humans exclusively
- Gastroenteritis
- caused by paratyphi, hirschfeldii,
and typhimurium
13
Q
Salmonella’s virulence factors
A
- its ability to adhere effectively to gut mucosa
- endotoxin
14
Q
Prevention and Treatment of Salmonella
A
- Avoid contact with bacteria
- trimethoprim-sulfamethoxazole (TS)
- when disease is severe
15
Q
Salmonella has a high ID50, meaning…
A
A lot of organisms must be ingested for disease to result
16
Q
Salmonella commonly found in
A
milk and eggs
17
Q
Shigella bacteria characteristics
A
- gram-negative rods
- non motile
- non-spore-forming
- primarily human parasites, but can infect Apes
18
Q
Signs and symptoms of Shigella
A
- Frequent, watery stools
- Fever
- Intense abdominal pain
- Nausea and vomiting are common
19
Q
Dysentery
A
- diarrhea containing blood
- Mucus from the GI tract is also present in the stools
20
Q
Virulence Factors of Shigella
A
- Shigella invades the villus cells of the large intestine rather than the small intestine
- Causes inflammatory response
- Enterotoxin
21
Q
Shiga Toxin
A
- Produced by Shigella dysenteriae
- may be responsible for more serious
damage to the intestine
- also causes systemic effects, including injury to nerve cells
22
Q
Transmission of Shigella
A
- Oral route
- direct person-to-person
- sanitation, malnutrition, and crowding
23
Q
True or False: Shigella can establish a chronic carrier condition in some people that can last several months
A
True
24
Q
Prevention and Treatment of Shigella
A
- Good hygeine
- trimethoprim-sulfamethoxazole (TS)
25
most virulent enterohemorrhagic E. coli or
EHEC
E. coli O157:H7
26
Signs and Symptoms of E. coli O157:H7
* Mild gastroenteritis, Fever, Bloody diarrhea
* 10% of patients develop severe hemolytic anemia in kidney and can cause kidney damage and failure
* Neurological symptoms such as blindness, seizure, and stroke
27
Virulence factors of E. coli O157:H7
* Shiga toxin
* interrupts protein synthesis on target cells
lesions in large intestines & produce bloody diarrhea
28
Transmission of E. coli O157:H7
* Most common mode of transmission for EHEC is **ingestion of contaminated or undercooked beef**
* other foods and beverages can be contaminated
* any farm product can become contaminated with cattle feces
* Products eaten raw such as **lettuce, vegetable, and apples used in unpasteurized cider** are particularly problematic
29
Culture and Diagnosis of E. coli O157:H7
stool culture or with ELISA or PCR
30
Prevention and Treatment of E. coli O157:H7
* never to eat raw or rare hamburger and to wash raw vegetables
* supportive therapy, including **plasma**
**transfusions** to dilute the toxin in the blood is the only option
* antibiotics may increase pathology
31
Campylobacter
Considered to be the most common bacterial
cause of diarrhea in the U.S
32
Signs and symptoms of Campylobacter
* Frequent, watery stools
* Fever
* Vomiting
* Headaches
* Severe abdominal pain
* Symptoms may last longer than 2 weeks
33
Causative agents of Campylobacter
Campylobacter jejuni
34
Transmission of Campylobacter
* ingestion of contaminated beverages and food
* water, milk, meat, and chicken
35
Yersinia
* Gram-negative bacteria
* includes the species Yersinia pestis,
* cause of the plague
36
Species of Yersinia that cause GI tract diseases
1. Y. enterocolitica
2. Y. pseudotuberculosis
37
GI Yersinia is often mistaken for what?
appendicitis
38
Clostridium difficile
Gram-positive endospore forming rod as normal flora
39
Signs and Symptoms of Clostridium difficile
* Diarrhea
* severe cases exhibit
* abdominal cramps
* Fever
* colon is inflammed and gradually sloughs off loose, membranelike patches called **pseudomembranes**
* if the condition is not stopped, perforation of the cecum and death can result
40
Virulence factors of Clostridium difficile
* Superinfection
* opportunistic
* Enterotoxin
* necrosis
41
Treatment of Clostridium difficile
* Replacement of lost fluids and electrolytes
* antibiotics in severe cases
42
Causative agent of Cholera
Vibrio cholerae
43
Signs and symptoms of cholera
* Abrupt symptoms of vomiting followed by copious, watery feces called **secretory diarrhea**
* contains flecks of mucus and is described as “rice water stool”
* Oodles of fluid loss
* sometimes up to 50% of body weight
* Potassium depletion
* If cholera is left untreated, death can occur in less than 48 hours & mortality rate approaches 55%
44
Virulence factors of cholera
* Cholera toxin
* fluid loss
45
Transmission of cholera
* Seasonal
* Water and food
46
Prevention and Treatment of Cholera
* Proper sewage treatment
* Vaccines available to travelers
* Prompt replacement of fluids and electrolytes
* Oral antibiotics: trimethoprim-sulfamethoxazole (TS)
47
GI Viruses
* Rota virus
* Adenoviruses
* noroviruses (Norwalk viruses)
* astroviruses
48
Transmission of GI viruses
* fecal-oral
* food contamination
49
Food poisoning should be suspected when...
* severe nausea and frequent vomiting accompanied by diarrhea
* patient reports that companion also has similar symptoms after eating the same thing
* onset within last 1-6 hours
50
Bacteria that produce the food poisoning toxin
* Staphylococcus aureus
* Bacillus cereus
* Clostridium perfringens
