Bacterial Infections of the GI Tract

Question 1

Non-inflammatory diarrhea vs inflammatory diarrhea

Answer 1

Non-inflammatory (e.coli) - ingestion of toxin causes elevations in cAMP and watery diarrhea.

Inflammatory (Shigella) - organism colonizes the intestine, cytotoxins cause inflammation, which causes diarrhea.

Question 2

What type of disease is cholera?

Answer 2

Toxin-mediated. Caused by vibrio cholerae.

Question 3

Vibrio cholerae characteristics

Answer 3

Curved/straight bacilli. Gram negative, 150o serotypes, but only 1 and 139 are cholerogenic.

Question 4

Where does vibrio cholerae live?

Answer 4

Aquatic environments

Question 5

Clinical symptoms of cholera

Answer 5

Devastating watery diarrhea, vomiting

Question 6

Main defense against cholera?

Answer 6

Gastric acidity

Question 7

How is cholera toxin created?

Answer 7

Lysogenic phage integrates into genome, activated when vibrio is in right temperature and sugar concentration.

Question 8

TCP pilus

Answer 8

On vibrio cholerae, important for attachment and colonization of vili.

Question 9

What type of toxin is choleratoxin?

Answer 9

AB toxin. 2 types of A’s. Increases cAMP in body.

Question 10

Therapy for choleratoxin?

Answer 10

Rehydration

Question 11

Shigella appearance

Answer 11

Non-lactose fermenting gram negative rods

Question 12

What does shigella cause?

Answer 12

Dysentery

Question 13

What are the symptoms of dysentery?

Answer 13

Small volume, bloody diarrhea. Abdominal cramps/pain, tenesmus (straining).

Question 14

What is the shigella reservoir?

Answer 14

Humans, transmitted from person to person, common in children.

Question 15

What part of shigella dysenteriae causes dysentery?

Answer 15

Shigatoxin shuts down cell and causes death.

Question 16

Salmonella species characteristics

Answer 16

Gram negative rods, facultatively anaerobic, motile, no fermentation of lactose/sucrose

Question 17

Which salmonella causes enteritis?

Answer 17

S. typhimurium

Question 18

Which salmonella causes typhoid fever?

Answer 18

S. typhi

Question 19

Salmonella gastroenteritis symptoms

Answer 19

N/V within 48 hours, urgency, diarrhea can vary.

Question 20

Typhoid fever.

Answer 20

Systemic disease with multiorgan disfunction. Prolonged fever, sustained bloodstream infection. Passes from stool to blood

Question 21

How can you get a non-thyphoidal salmonella infection?

Answer 21

Agricultural products like eggs, processed food like dairy, domestic animals like iguanas.

Question 22

How is salmonella pathogenic

Answer 22

Survives within macrophages and other non-phagocytic cells, encapsulated

Question 23

How can you get a campylobacter infection?

Answer 23

Handling chicken. Little person to person transmission.

Question 24

What is the worst case scenario w/campylobacter?

Answer 24

Guillain Barre syndrome. Most of the time the disease is self-limiting.

Question 25

Heliobacter Pylori

Answer 25

Causes gastric ulcers, not diarrhea. CLASS 1 CARCINOGEN (gastric adenocarcinoma and MALT lymphoma).

Question 26

Antibiotic treatment for vibrio, campylobacter, salmonella, shigella

Answer 26

Fluoroquinolones, 3rd generation cephalosporins, macrolides. Frequently resistant to amoxicillin, TMPSMZ and 1st generations cephs.