Chapter 20: Infectious Diseases Affecting the Gastrointestinal Tract- Part 2

Question 1

Shigellosis classic symptom

Answer 1

Dysentery (bloody diarrhea)

Question 2

Other symptoms of shigellosis

Answer 2

Headache
Vomiting
Fever
Stiff neck
Convulsions
Joint pain

Question 3

Shigellosis is commonly ___ for infants in developing countries

Answer 3

Fatal

Question 4

Causative agent (s) of shigellosis

Answer 4

Four species of Shigella
S. flexnuri
S. boydii
S. sonnei
S. dysenterriae
(All cause shigellosis)

Question 5

S. dysenteriae is ____ encountered in the US

Answer 5

Rarely

Question 6

S. dysenteriae produces..

Answer 6

Potent A-B toxin

Shiga toxin

Question 7

The shiga toxin acts much like a ______ toxin and is associated with…

Answer 7

Cholera

Fatal hemolytic uremic syndrome

Question 8

What accounts for the blood in diarrhea in shigellosis?

Answer 8

Inflammatory response

Question 9

First step in shigellosis pathogenesis

Answer 9

Shigellas are taken up by M cells and transported beneath epithelium. Macrophages take up shigella, die and release the bacteria

Question 10

Second step in shigellosis pathogenesis

Answer 10

The bacteria enter the inferior and lateral aspects of the epithelial cells by inducing endocytosis. The endoscopes are quickly lysed, leaving the shigella free in the cytoplasm

Question 11

Third step in shigellosis pathogenesis

Answer 11

Actin filaments quickly form a tail, pushing the shigella into the next cell

Question 12

Fourth step in shigellosis pathogenesis

Answer 12

Shigellas multiply in the cytoplasm and the infection extends to the next cell

Question 13

Last step in shigellosis pathogenesis

Answer 13

Infected cells die and slough off. Intense response of acute inflammatory cells (neutrophils), bleeding and abscess formation

Question 14

Shigellosis source of transmission

Answer 14

Human, Fecal-oral

Question 15

Are shigellosis bacteria easily killed by stomach acid?

Answer 15

No so they have a low infecting dose, as few as 20 organisms!

Question 16

Transmission of shigellosis occurs most often as a result of..

Answer 16

Overcrowding

• Also daycares and homosexual men
• Contaminated water

Question 17

Shigellosis is controlled by..

Answer 17

Sanitary measures and surveillance of food handlers and water supplies

Question 18

Is there a vaccine for shigellosis?

Answer 18

No

Question 19

Most important treatment of shigellosis is….

Answer 19

Fluid and electrolyte replacement

Question 20

_________ are often used to shorten duration of symptoms of shigellosis

Answer 20

Antimicrobials

Question 21

Antimicrobials can also be used to..

Answer 21

Shorten time that bacteria is discharged in feces

Question 22

___ % of Shigella species are resistant to antibiotics of choice

Answer 22

20

Question 23

________ used to be the drug of choice for shigellosis but now it is…

Answer 23

Ampicillin

Newer penicillins or Ciprofloxacin

Question 24

Clostridium Difficile signs and symptoms

Answer 24

Diarrhea commencing in late antibiotic therapy or even after therapy has stopped

Question 25

Severe cases of C diff exhibit..

Answer 25

Abdominal cramps, fever and leukocytosis

Question 26

With C diff, the colon is inflamed and gradually..

Answer 26

Sloughs off loose, membrane like patches called pseudomembranes

Question 27

If c diff is not stopped…

Answer 27

Perforation of the cecum and death can result

Question 28

C diff causative agent

Answer 28

Clostridium difficile (gram-positive endospore forming rod)

Question 29

C diff is able to superinfection the large intestine when…

Answer 29

Drugs hace interrupted the normal biota

Question 30

C diff produces _ and _ enterotoxins

Answer 30

A

B

Question 31

A and B enterotoxins cause..

Answer 31

Necrosis in the large intestine

Question 32

C diff are now known to cause a condition called…

Answer 32

Pseudomembranous colitis

Question 33

C diff is a major cause of diarrhea in…

Answer 33

Hospitals (community - acquired infections)

Question 34

Uncomplicated cases of C diff respond to…

Answer 34

Withdrawal of antibiotics and replacement therapy for lost fluids and electrolytes

Question 35

More severe cases of C diff are..

Answer 35

Treated antibiotics for several weeks until the intestinal biota return to normal
Vancomycin
Fidaxomciin

Question 36

New treatment techniques of C diff

Answer 36

Vaccination (toxoid, not approved yet)
Probiotics
Fecal transplant
Restoration of normal biota by ingestion of a mixed culture of lactobacilli and yeasts

Question 37

Vancomycin

Answer 37

Cell wall synthesis inhibitor for gram +

Question 38

Fidaxomicin

Answer 38

Nucleic acid synthesis inhibitor especially effective for clostridium