Infections of the Gastrointestinal Tract

Question 1

What areas of the GI tract are usually mostly sterile?

Answer 1

Stomach and small intestine

Question 2

What % of the immune system is in the gut?

Answer 2

80%

Question 3

Where are normal microbiotia confined to?

Answer 3

Mouth and large intestines

Question 4

What are the types of foodborne diseases?

Answer 4

Food Poisoning and food infection

Question 5

What is food poisoning?

Answer 5

Disease that results from ingestion of foods containing preformed microbial toxins. The microorganisms that produced the toxins do not have to grow in the host

Question 6

What is food infection?

Answer 6

microbial infection resulting from the ingestion of pathogen-contaminated food followed by growth of pathogen in the host

Question 7

What type of foodborne disease is clostridium perfringens and clostridium botulinum and what do they produce?

Answer 7

clostridial food poisoning.- can cause paralysis. Produce exotoxin, botulinum toxin, and tough endospores that are hard to kill.

Question 8

How is clostridium difficile transmitted?

Answer 8

Person to person by the fecal-oral route.

Question 9

How is c.difficile hard to kill?

Answer 9

Forms heat resistant spores, aren’t killed by alcohol-based cleanser or routine cleaning and survive for long periods of time.

Question 10

Once c.diff is ingested

Answer 10

Acid-resistance allows them to ass through stomach and upon exposure to bile acids they germinate and multiply into cells in the colon.

Question 11

Why can’t antibiotics not be used to treat c.diff?

Answer 11

Antibiotics disrupt the normal intestinal flora which can lead to an overgrowth of c.diff as it flourishes under these conditions

Question 12

What is colitis associated with severe infection?

Answer 12

Pseudomembranous colitis is the inflammation of the large intestines/colon. Part of an inflammatory reaction with the pseudomembrane formed by a viscous collection of inflammatory cells, fibrin and necrotic cells.

Question 13

What is the only affective treatment for c.diff?

Answer 13

Faecal transplants

Question 14

What is salmonellosis?

Answer 14

A gastrointestinal illness caused by foodborne salmonella infection= food infection.

Question 15

How is salmonella caused?

Answer 15

Caused by eating food contaminated with Salmonella or handling salmonella-infected animals.

Question 16

How does salmonella act once ingested?

Answer 16

Invades phagocytes and grows as an intracellular pathogen.

Question 17

Salmonella bacteria are

Answer 17

gram negative rod-shaped facultative anaerobe (flagellated), which cause enterocolitis, enteric fevers and septicaemia

Question 18

What is enterocolitis?

Answer 18

Invasion between mucosal cells causing inflammation and diarrhoea.

Question 19

What are the two categories of salmonellae?

Answer 19

• Typhoidal species

- Non-typhoidal or enterocolitis species

Question 20

What us typhoid

Answer 20

An enteric fever caused by infection with salmonella enterica serotype typhi

Question 21

How is S. typhi transmitted?

Answer 21

Through faecal oral route (food, water). Humans are the only reservoir for it. People can be chronic asymptomatic carriers posing risk to others, particularly in preparing food

Question 22

How can S.typhi be prevented?

Answer 22

Vaccine

Question 23

First week classic clincal features of typhoid fever

Answer 23

stepwise rising fever, bacteremia

Question 24

Second week classic clinical features of typhoid fever

Answer 24

abdo pain and “rose spots” on trunk and abdo

Question 25

Third week classic clinical features of typhoid fever

Answer 25

liver and spleen inflammation, intestinal bleeding, peritonitis, septic shock and death

Question 26

Widal test for O antigens of different strains of Salmonella enterica will show what on positive and negative tests?

Answer 26

Postive: Agglutination within a minute

Negative test: No agglutination

Question 27

Treatment of Salmonella

Answer 27

Fluroqinolones, 3rd generation cephalosporins such as ceftriaxone, azithromycin.

Question 28

What attributes do noroviruses have that makes them an ideal infectious agents?

Answer 28

High contagious, rapidly and prolifically shed, constantly evolving (changes its genome), evoking limited immunity, and only moderately virulent.

Question 29

Why is norovirus so contagious? How many copies of norovirus on average does it take to get sick?

Answer 29

Little amount of copies of the virus are need to make a person sick. Approx. 9 copies.

Question 30

What type of virus is norovirus? what is its genetic material?

Answer 30

RNA virus. Calicivirus- known for being very infectious

Question 31

How is norovirus transmitted?

Answer 31

droplet, contact with faeces or vomit. Vomiting is the most efficient way to spread to virus.

Question 32

How is the causative agent of gastroenteritis diagnosed?

Answer 32

Stool sample- PCR (RTPCR), culture on agar & symptoms

Question 33

What puts you at risk of getting norovirus?

Answer 33

Living in close proximity to others, and being immunocompromised

Question 34

What treatment should be given for norovirus?

Answer 34

Fluids

Question 35

How to prevent norovirus?

Answer 35

Isolate infected individuals, barrier nursing, hand hygiene, food hygiene, and stay away from work for 48 hours.