Chapter 25: Microbial Diseases of the Digestive System Flashcards Preview

GSU Microbiology > Chapter 25: Microbial Diseases of the Digestive System > Flashcards

Flashcards in Chapter 25: Microbial Diseases of the Digestive System Deck (73):
1

Which of the following is included in GALT?

salivary glands
liver
Peyer's patches
tonsils
thymus

Peyers patches

2

Bacteria present in the __________ can be phagocytosed by Paneth cells.

large intestine
stomach
small intestine
mouth

small intestine

3

Dental plaque is an

gingivitis.
dentin.
a biofilm.
a pellicle.
tooth enamel.

a biofilm.

4

Clostridium difficile-associated diarrhea is usually preceded by

improper food storage.
travel to an underdeveloped country.
extended use of antibiotics.
a blood transfusion.
eating contaminated food.

extended use of antibiotics.

5

Poultry products are a likely source of infection by

Salmonella enterica.
Shigella spp.
Clostridium perfringens.
Helicobacter pylori.
Vibrio cholerae.

Salmonella enterica.

6

Epidemics related to bacterial infection of the digestive system are typically caused by

contaminated food and water.
unpasteurized milk.
the respiratory route.
exposure to contaminated soil.
biological vectors.

contaminated food and water.

7

Helicobacter pylori can grow in the stomach because it

makes HCl.
hides in macrophages.
possesses an enzyme that neutralizes HCl.
makes a capsule.
invades epithelial cells

possesses an enzyme that neutralizes HCl.

8

Aflatoxin is a(n) ________ associated with ingestion of contaminated ________.

endotoxin; peanuts
mycotoxin; rye or other cereal grains
enterotoxin; peanuts
mycotoxin; peanuts
enterotoxin; rye or other cereal grains

mycotoxin; peanuts

9

Which of the following symptoms is LEAST characteristic of Clostridium perfringens food poisoning?

short incubation period
sudden onset of diarrhea
severe abdominal cramping
moderate vomiting and fever

Vomiting and fever are not characteristic of C. perfringens poisoning.

10

Cholera is a waterborne pathogen that causes severe gastrointestinal disease. The organism is a slightly curved, gram-negative rod that likes to grow in the small intestine and causes watery stools and violent vomiting. Complete the following statement: Cholera is caused by the bacterium, __________ and produces __________ that result in severe diarrhea.

Vibrio cholera; exotoxins

The causative agent of cholera is Vibrio cholerae. This organism is a curve-shaped, gram-negative rod. It produces cholera toxin, which is an exotoxin that causes infected individuals to experience extreme diarrhea and vomiting.

11

Which of the following has the greatest impact on the number of cholera cases after a natural disaster?

increases in the rodent population
dead bodies piling up in the streets
flood waters mixed with ocean water
sewage contamination in drinking water

sewage contamination in drinking water

12

The pathogenesis of Vibrio cholerae is due to the organism’s ability to produce cholera toxin. This is an A-B toxin that affects host cells in the small intestine. Which of the following correctly describes the mechanism of the toxin?

The cholera toxin binds to nerve cells and inhibits the release of neurotransmitters.
The cholera toxin causes the host cells to secrete large amounts of fluids and electrolytes.
The cholera toxin produces a superantigen and symptoms associated with toxic shock syndrome.
The cholera toxin binds to nerve cells and inhibits the relaxation of muscles.

The cholera toxin causes the host cells to secrete large amounts of fluids and electrolytes.

13

Which of the following organisms is most likely the causative agent of foodborne of tapeworm infection?

Ascaris lumbricoides
Taenia saginata
Taenia solium
Enterobius vermicularis

Taenia solium is the tapeworm associated with eating undercooked pork. Eggs and proglottids from the adult tapeworm are released in the intestines and can be observed in fecal samples with a light microscope. Diagnosis is based on these findings.

14

Explains why the tapeworm is flat?

Tapeworms utilize diffusion to absorb nutrients from the host’s digestive system.

15

The correct sequence of events for the life cycle of the pork tapeworm, T. solium?

1. eggs are produced by adult tapeworms living in the definitive host
2. eggs are released to the environment in the feces
3. pigs eat grass contaminated, or fertilized, with human feces.
4. inside the intermediate host, the eggs mature into larvae and encyst in the hosts muscles
5. the definitive host ingests the eggs and becomes infected

The adult worm produces thousands of eggs in the human host. These eggs leave the digestive tract via the feces. When pigs eat grass contaminated with, or fertilized by, human feces they become infected with T. solium. The tapeworm eggs mature into larvae that encyst themselves in the muscle tissue of the pig. When humans eat pork that has not been cooked to high enough temperatures, they become infected with the tapeworm.

16

Why do we see an increase in the levels of IgE antibody in infected tapeworm serum?

IgE is the class of antibodies involved in hypersensitivities such as allergies and parasitic infections.

17

Effective treatment against tapeworms.

Praziquantel or albendazole, drugs that target eukaryotic parasites with minimal side effects in the host.

18

Normal Microbiota

-millions of bacteria per ml of saliva
-large numbers in large intestine
-100 billion bacteria per gram of feces

19

Defenses of the human digestive system

-Stomach; acidic
-small intestines; paneth cells
-Defensins and lysozyme

20

What is Dental Caries?

It is Tooth Decay

21

Stages of Dental Caries

-S.mutans attaches to proteins on tooth
-Eat sucrose to produce dextran
-Bacteria accumulate on dextran=dental plaque
-Ferment sugar to produce lactic acid
= cavity

22

Explain Disease of Lower Digestive System

Infection
Intoxication
Gastroenteritis
Treatment

1. infection: growth of a pathogen
*incubation is from 12 hours to 2 weeks
*fever
2. ntoxication: ingestion of toxin
*symptoms appear 1 to 48 hours after ingestion
3. Gastroenteritis: Diarrhea, dysentery
4. Treatment: Oral rehydration therapy

23

Staphylococcal food poisoning

Pathogen: Staphyloccus aureus

Symptoms: Nausea, vomiting, and diarrhea

Intoxication/infection: intoxication, enterotoxin (superantigen)

Diagnosis: phage typing

Treatment: none

24

Salmonellosis

characteristics of disease

Pathogen: Salmonella enterica
Symptoms: Nausea and diarrhea
Intoxication/infection: infection endotoxin
Diagnosis: Isolation of bacteria; serotyping
Treatment: oral rehydration

25

Typhoid Fever

Characteristics of disease

-Pathogen: S.typhi
-Symptoms: High fever, significant mortality
-Intoxication/infection: Infection endotoxin
-Diagnosis: isolation of bacteria; serotyping
-Treatment: Quinolones; cepholosporins
-Caused by Salmonella tyhpi
-Bacteria spread throughout body in phagocytes
-1-3% of recovered patients become chronic carrier

26

Helicobater Peptic Ulcer Disease

Pathogen: Helicobacter pylori
Symptoms: peptic ulcers
Intoxication/infection: infection
Diagnosis: Urea breath, bacterial culture
Treatment: antimicrobial drugs

27

Cryptosporidiosis

Pathogen: Cryptosporidium hominis
Symptoms: self-limiting diarrhea; may be life-threatening in immunosuppressed people
Reservoir: cattle, water
Diagnosis: Acid-fast stain; FA; ELISA
treatment: oral rehydration

28

Amoebic Dysentery

Pathogen: Entamoeba histolytica
Symptoms: Abscesses; significant mortality rate
Reservoir: humans
Diagnosis: microscopy; serology
treatment: Metronidazole

29

Acute gastroenteritis that occurs after an incubation period of two to three days and commonly affects children is probably caused by

rotavirus.

30

Aflatoxin is a(n) ________ associated with ingestion of contaminated ________.

mycotoxin; peanuts

31

All of the following are eukaryotic organisms that cause diarrheal disease EXCEPT

Campylobacter.
Cyclospora.
Giardia.
Cryptosporidium.
Entamoeba

Campylobacter.

32

All of the following are gram-negative rods that cause gastroenteritis EXCEPT

Clostridium perfringens.
Yersinia enterocolitica.
Escherichia coli.
Shigella spp.
Salmonella typhi.

Clostridium perfringens.

33

All of the following infections can result form drinking contaminated water EXCEPT

trichinellosis.
cholera.
giardiasis.
cryptosporidiosis.
Cyclospora infection.

trichinellosis.

34

All of the following pertain to pinworm infections EXCEPT

A. it is a helminth disease.
diagnosis is by detecting eggs on transparent tape pressed to the perianal area.
B. transmission is typically by contact with fomites or inhalation of eggs.
all family members living with the patient must also be treated.
C. it is most commonly transmitted by cysts in water.
D. Bacterial intoxications differ from bacterial infections of the digestive system in that intoxications

it is most commonly transmitted by cysts in water

35

Bacterial intoxications differ from bacterial infections of the digestive system in that intoxications

have shorter incubation times.

36

The digestive tract is essentially one long tube. The order of the structures, beginning with the mouth, is

pharynx, esophagus, stomach, small intestine, large intestine.

37

Epidemics related to bacterial infection of the digestive system are typically caused by
.

contaminated food and water

38

Gums bleeding while brushing ones teeth is most commonly associated with

gingivitis

39

The most common cause of traveler's diarrhea is

Escherichia coli.

40

The most common mode of HAV transmission is

contamination of food during preparation.

41

Most of the normal microbiota of the digestive system are found in the

small intestine and large intestine.

42

A patient exhibits hemorrhagic colitis and is treated via intravenous rehydration. The pathogen is a gram-negative rod. It is isolated and differentiated from related organisms based on its inability to ferment sorbitol. Which of the following is a likely diagnosis?

Escherichia coli gastroenteritis

43

A patient presents with diarrhea that has lasted for weeks and is accompanied by malaise, flatulence, weight loss, and abdominal cramps. You detect the odor of sulfur on his breath. Based on the signs and symptoms, you suspect __________, a protozoan. It is not easily found in stool samples, so you do a string test.

giardiasis

44

Rice water stools" are characteristic of

cholera

45

Typhoid fever differs from salmonellosis in that in typhoid fever

the incubation period is much longer.

46

A vaccine to provide active immunity to HBV is prepared from

genetically modified yeast.

47

What do hepatitis A and hepatitis B have in common?

Both can be prevented by a vaccine.

48

What is a Dane particle?

the infectious virion that causes HBV

49

What organ is most affected by hepatitis B virus?

Liver

50

Which of the following causes inflammation of the liver?

Hep A

51

Which of the following diseases of the gastrointestinal system is transmitted by the respiratory route?

mumps

52

Which of the following helminthic diseases is a common infestation found in the southeastern United States?

Ascaris lumbricoides

53

Which of the following is directly involved in the initiation of dental caries?

lactic acid

54

Which of the following NOT true for both hepatitis B and hepatitis C infection?

The virus can cause a chronic disease.
The infection is transmitted through blood and body fluids.
Diagnosis can be achieved through testing the blood for antibodies.
The disease is prevented by vaccination.

The disease is prevented by vaccination.

55

Which of the following organisms feeds on red blood cells?

Entamoeba histolytica

56

Which of the following organisms is likely to be transmitted via contaminated shrimp?

Vibrio parahaemolyticus

57

Which of the following organisms is likely to be transmitted via undercooked pork and horse?

Trichinella spiralis

58

Which of the following statements about salmonellosis is FALSE?
A. A healthy carrier state exists.
B. It is a bacterial infection.
C. Severity of disease depends on number of organisms ingested.
D. It is often associated with poultry products.
E. The mortality rate is high.

E. The mortality rate is high

59

Which of the following statements about staphylococcal food poisoning is FALSE?

A. It is characterized by rapid onset and short duration of symptoms.
B. It is treated by replacing water and electrolytes.
C. It is caused by ingesting an enterotoxin.
D. It can be prevented by adequate refrigeration of food.
E. It can be prevented by heating foods to 50°C for 15 minutes.

E. It can be prevented by heating foods to 50°C for 15 minutes.

60

Which of the following statements concerning mumps virus infection is FALSE?

A. The virus is present in urine approximately 10 days after the onset of symptoms.
B. The illness frequently begins with painful swelling of one or both parotid glands.
C. The virus is transmitted in saliva and respiratory secretions.
D. The testes can become inflamed about 2 to 3 weeks after the onset of symptoms.

D. The testes can become inflamed about 2 to 3 weeks after the onset of symptoms.

61

Ergot poisoning __________.

a) is caused by the ingestion of contaminated peanuts
b) may cause hallucinogenic symptoms
c) contributes to liver cirrhosis and cancer
d) is a disease caused by the fungus Aspergillus flavus

b) may cause hallucinogenic symptoms

62

Vaccines can be used to protect at-risk individuals from all of the following liver diseases EXCEPT

a) hepatitis C
b) hepatitis D
c) hepatitis A
d) hepatitis B

a) hepatitis C

63

Worldwide, __________ cause one of the most common helminthic infections. Diagnosis is frequently made when a worm emerges from the anus, mouth, or nose.
a) tapeworms
b) Trichinella
c) hookworms
d) Ascaris lumbricoides

d) Ascaris lumbricoides

64

How do Shigella cells move between host cells?

They can polymerize actin molecules from the epithelial cells into tail-like structures that propel them from one cell to another

65

What is the etiologic agent of typhoid?

Salmonella

66

The term dermatophyte is typically used for fungi that cause which of the following?

cutaneous mycoses

67

Helminthic diseases are usually transmitted to humans by

gastrointestinal route.

68

The encysted larva of the beef tapeworm is called a

cysticercus.

69

A definitive host harbors which stage of a parasite?

adult

70

What do tapeworms eat?

intestinal contents

71

Ringworm is caused by a(n)

fungus

72

Yeast infections are caused

Candida albicans.

73

What is the key difference between yeast and mold?

Yeast is unicellular, while mold is multicellular.