GI Acute Inflammatory Diarrhea II

Question 1

describe the shape of Campylobacter

Answer 1

small, curved-spiral rods

Question 2

Campylobacter are (G+ve/G-ve) and are motile

Answer 2

Campylobacter are G-ve and are motile

Question 3

Campylobacter are G-ve and are (motile/non-motile)

Answer 3

Campylobacter are G-ve and are motile (single polar flagellum)

Question 4

Campylobacter are microaerophilic and DO NOT ferment ____

Answer 4

Campylobacter are microaerophilic and DO NOT ferment CH2O (carbohydrates)

Question 5

Campylobacter are (catalase +ve/catalase -ve)

Answer 5

Campylobacter are catalase +ve

Question 6

____ are the leading cause of bacterial food-borne disease

60% of cases are caused by….

Answer 6

Campylobacter are the leading cause of bacterial food-borne disease

60% of cases are caused by ingestion of contaminated liquid or solid food (unpasteurized milk, raw/partially cooked poultry & contaminated water)

Question 7

describe the pathogenesis of Campylobacter

Answer 7

1. ingestion of pathogen
2. invasion of SI and LI
   
   • histologic damage to mucosal surfaces
3. toxin production
   
   • endotoxin (since it is inherent to G-ve)
   • enterotoxin: watery diarrhea
   • cytotoxin: verotoxin similar to Shiga toxin

Question 8

describe the clinical features of Campylobacter infection

Answer 8

symptoms appear 3-5 days after ingestion

• vomiting
• diarrhea (often profuse, green?)
• abdominal pain, often severe
• prostration, often severe
• fever, often present
• bloodstained feces

Question 9

name associations/complications of Campylobacter

Answer 9

• reactive arthritis
  
  • knee joint
• acute inflammatory demyelinating polyneuropathy; Guillan-Barre syndrome

Question 10

describe how Campylobacter infection can lead to GBS

Answer 10

Question 11

describe the detection of C. jejuni

Answer 11

Question 12

describe the Sketchy

Answer 12

Question 13

Yersinia enterocolytica is common among _____ (population)

Answer 13

Yersinia enterocolytica is common among children <7 yrs old and adults

Question 14

describe the growth temperature of Yersinia enterocolytica

Answer 14

-1 to 40 C = psychrotroph - facultative psycrophiles

(grows in ​cold temperatures)

Question 15

describe the pathogenesis of Yersinia enterocolytica

Answer 15

• invasive induces inflammatory response
• distal ileum (gut-associated lymphoid tissue)
• adjacent tissues & mesenteric lymph nodes also infected (mimic appendicitis)
• releases chromosomally encoded ST enterotoxin (which leads to an increase in cGMP)

Question 16

Yersiniosis infects adjacent tissues in the distal ileum and mesenteric lymph nodes and often mimics ____

Answer 16

Yersiniosis infects adjacent tissues in the distal ileum and mesenteric lymph nodes and often mimics appendicitis

Question 17

the ___ enterotoxin produced by Y. enterocolytica is ___-encoded and causes a rise in ____

Answer 17

the ST enterotoxin produced by Y. enterocolytica is chromosomally-encoded and causes a rise in cGMP

Question 18

describe the clinical features of Y. enterocolytica

Answer 18

• self-limiting enterocolitis
• incubation = 3-7 days
• lasts 14-21 days
• symptoms:
  
  • abdominal pain and diarrhea
  • mild fever
  • vomiting rare

Question 19

Yersiniosis has an incubation period of ____ and lasts for _____

Answer 19

Yersiniosis has an incubation period of 3-7 days and lasts for 14-21 days

Question 20

Yersiniosis can lead to post-infective _____

Answer 20

Yersiniosis can lead to post-infective reactive arthritis (autoimmunity arthritis)

Question 21

Y. enterocolytica looks like ____ colonies on MacConkey agar

Answer 21

Y. enterocolytica looks like pinpoint colonies on MacConkey agar

Question 22

describe the Sketchy

Answer 22

Question 23

V. parahaemolyticus infection is caused by ingestion of ____

Answer 23

V. parahaemolyticus infection is caused by ingestion of raw/poorly cooked seafood

Question 24

V. vulnificus is associated with abrasions/cuts exposed to ____

Answer 24

V. vulnificus is associated with abrasions/cuts exposed to sea/salt water

Question 25

V. parahaemolyticus produces ___ and \_\_\_\_

Answer 25

V. parahaemolyticus produces **enterotoxin** and **haemolysin**

Question 26

describe signs of V. vulnificus

Answer 26

* intense **skin lesions** * **gastroenteritis** & even **severe bacteremia**

Question 27

deaths caused by V. vulnificus are predominantly associated with patients with \_\_\_\_\_

Answer 27

deaths caused by V. vulnificus are predominantly associated with patients with **underlying liver conditions**

Question 28

describe diagnosis and ID of non-cholera species

Answer 28

Question 29

enteroaggregative E. coli (EAEC) does NOT possess ____ but does possess _____ which allows it to aggregate on the surface of SI/LI

Answer 29

enteroaggregative E. coli (EAEC) does NOT possess **EAF (enteric adherence factor)** but does possess **AAF (aggregative adherence factor)** which allows it to aggregate on the surface of SI/LI

Question 30

describe the pathogenesis of EAEC

Answer 30

1. agglutination of bacteria 2. adherence to intestinal epithelium and colonization 3. formation of biofilm 4. release of toxins (damage to epithelium + increased secretion) 5. establishment of additional biofilm

Question 31

name the 3 life-threatening conditions caused by EHEC/STEC/VTEC

Answer 31

* hemorrhagic colitis = approx. 3 days after ingestion * mainly adults/elderly * blood diarrhea (begins watery) * hemolytic uremic syndrome (HUS) = 5-13 days post-diarrhea * mainly affects children * microangiopathic hemoltyic anemia * thrombocytopenia * acute renal failure * thrombotic thrombocytopenia purpura * mainly elderly * HUS + fever + neurological involvement

Question 32

hemorrhagic colitis, caused by \_\_\_\_, occurs ___ days after ingestion and affects mainly \_\_\_\_

Answer 32

hemorrhagic colitis, caused by **STEC/VTEC/EHEC**, occurs **~3** days after ingestion and affects mainly **adults/elderly**

Question 33

hemolytic uremic syndrome, caused by \_\_\_\_, occurs ___ days after diarrhea and affects mainly \_\_\_\_

Answer 33

hemolytic uremic syndrome, caused by **STEC/VTEC/EHEC**, occurs **5-13 days post-diarrhea** and affects mainly **children**

Question 34

thrombotic thrombocytopenia purpura, caused by \_\_\_\_, affects mainly \_\_\_\_

Answer 34

thrombotic thrombocytopenia purpura, caused by **STEC/VTEC/EHEC**, affects mainly **elderly**

Question 35

describe the pathogenesis of STEC/VTEC/EHEC

Answer 35

1. ingestion 2. attachment (similar to EPEC) 3. production of phage-encoded: cytotoxin (verotoxin) * 2 types VT1 and VT2, both AB toxins * Shiga-like toxin (rRNA) blocks protein synthesis 4. hemorrhagic colitis 5. toxin enters circulation binds to glomerular endothelium 6. hemolytic anemia, renal damage → renal failure

Question 36

STEC/VTEC/EHEC is also associated with \_\_\_\_\_

Answer 36

STEC/VTEC/EHEC is also associated with **county fairs/petting zoos**

Question 37

STEC do not ferment ____ and therefore appear colorless on MacConkey's agar

Answer 37

STEC do not ferment **sorbitol** and therefore appear colorless on MacConkey's agar

Question 38

in order to diagnose STEC, a blood culture can be taken and ____ can be seen

Answer 38

in order to diagnose STEC, a blood culture can be taken and **schistocytes (fragmented RBCs)** can be seen

Question 39

describe the Sketchy

Answer 39

Question 40

describe the identification of G-ve rods grown on MacConkey agar

Answer 40