GI 6

Question 1

similar to shigellosis but less severe ..and what does shigellosis have that this condition does not

Answer 1

enteroinvasive e. coli (EIEC)

does not have a shiga toxin

Question 2

pathogenesis of enteroinvasive e. coli (EIEC)

Answer 2

invades the enterocytes of LI (like shigellosis)

Question 3

what are the different types of salmonella genus based on

Answer 3

Vi antigens (capsular)

Question 4

3 clinical manifestations of salmonella

Answer 4

gastroenteritis, septicemia/bacterial, enteric (typhoid) fever

Question 5

bacteria associated enteric typhoid fever

Answer 5

Salmonella Typhi

Question 6

tests that you order for the different symptoms of salmonella

Answer 6

• enterocolitis: positive in stool culture soon after test but not seen in blood
• septicemia/bacteremia: pos in blood culture during high fever and sometimes seen in stool
• enteric typhoid fever: pos in blood culture for 1st and 2nd week then pos from 2nd week and on in stool

Question 7

pathogenesis of salmonella

Answer 7

they all will invade SI and sometimes LI but only septicemia/bacteremia will go the lymphatics then enter the blood and become systemic

Question 8

what harbors salmonella that leads to enterocolitis/gastroenteritis

Answer 8

it is food borne infection and seen mainly in dairy/poultry products

Question 9

who is mainly infected with reptile associated salmonella

Answer 9

infants and children through direct or indirect contact

Question 10

who in the US is infected with enteric typhoid fever

Answer 10

those that have travelled to Asia, Mexico, and India

Question 11

what occurs if enteric typhoid fever goes systemic

Answer 11

it can enter the liver/gall bladder and replicate in the bile and then bile enter the SI and reinfects leading to inflammation and ulceration

of course if it gets to SI –> seen in feces

Question 12

types of people who are important/dangerous in the transmission of typhoid fever

Answer 12

carriers because they have no symptoms but yet shed and infect others

Question 13

how can you prevent transmission of typhoid fever

Answer 13

take out the gall bladder so there will be no site for microbe to multiply and shed in feces

Question 14

how do you isolate and detect salmonella

Answer 14

use McConkey’s agar or S-S agar (salmonella -shigella agar)

Question 15

what do you see on S-S agar for salmonella

Answer 15

colorless/pale because salmonella does not do lactose fermentation

Question 16

how do you differentiate salmonella from shigella

Answer 16

salmonella is motile while shigella is not
salmonella uses gas from glucose
salmonella does H2S production and shigella does not (with the exception of s. flexnieri)

Question 17

diagnostic feature of s. typhi

Answer 17

• S-S agar
• history of travel to endemic areas like Asia, Mexico, and India
• Positive widal reaction
• gram neg, motile bacteria

Question 18

morphological feature of campylobacter

Answer 18

gram neg, motile, microaerophilic, does not ferment CH2O, and catalase positive

Question 19

carrier of campylobacter coli

Answer 19

pigs

Question 20

in general, how does one get infected with campylobacter

Answer 20

fecal contaminated water
unpasteurized milk
raw/partially cooked poultry

Question 21

toxins of campylobacter

Answer 21

• endotoxin
• enterotoxin –> watery diarrhea
• cytotoxin: verotoxin (similar to shiga toxin) –> bloody diarrhea

Question 22

clinical symptoms of campylobacter

Answer 22

symptoms begin 3-5 days after ingestion

• pyrexia (raised temp - fever)
• prostration
• abdominal pain
• diarrhea

Question 23

complications of campylobacter

Answer 23

• reactive arthritis

- guillian barre (aka acute motor axonal neuropathy) which is a symmetric ascending paralysis

Question 24

detection of c. jejuni

Answer 24

fecal specimen culture –> gram neg, motile, catalase pos, microaerophilic, needs 10% CO2

Question 25

Yersinia enterolytica is common in what age group

Answer 25

children under the age of 7

Question 26

what other condition rivals yersinia enterolytica

Answer 26

salmonella acute gastroenteritis because of commonality in cooler climates yersinia is a pyschrotroph - facultative psyhcrophile

Question 27

pathogenesis of yersinia enterolytica

Answer 27

releases a ST enterotoxin that increases cGMP --> watery diarrhea induces invasive inflammation in the distal ileum and adjacent tissues and mesenteric lymph node hence mimicking appendicitis

Question 28

treatment of yersinia enterolytica

Answer 28

doxycycline and oxytetracycline

Question 29

complication of yersinia enterolytica

Answer 29

post-infective reactive arthritis (autoimmunity arthritis)

Question 30

what are the non cholera vibrios

Answer 30

v. parahemolyticus v. alginolyticus v. vulnificus v. cholerae (non toxigenic v. cholerae)

Question 31

features of non cholerae vibrios

Answer 31

``` not agglutinated by anti 01 sera halophilic organisms (common coastal waters) ```

Question 32

how does one get vibrio parahemolyticus and in what area of the world is it common

Answer 32

from eating raw or undercooked seafood | common in Japan - they eat raw fish (sushi)

Question 33

how does one get infected with vibrio vulnificus

Answer 33

eating raw oysters

Question 34

clinical features of vibrio vulnificus

Answer 34

it is a virulent strain | get intense skin lesions --> gastroenteritis and severe bacteremia

Question 35

how do you diagnose vibrio

Answer 35

screening stool for oxidase activity TCBS agar - thiosulfate citrate bile salt sucrose agar --> sucrose negative will be vibrio parahemolyticus and vibrio vulnificus

Question 36

what does enteroaggregative possess

Answer 36

AAF - aggregative adherence factor

Question 37

another name for STEC - shiga toxin producing e. coli

Answer 37

VTEC - verotoxin producing e. coli

Question 38

what can STEC/VTEC cause

Answer 38

hemorrhagic colitis hemolytic uremic syndrome thrombotic thrombocytopenia purpura

Question 39

which one of the STEC/VTEC affect adults and which children and which elderly

Answer 39

hemorrhagic colitis - adults hemolytic uremic syndrome - children thrombotic thrombocytopenia purpura - elderly

Question 40

toxin released by VTEC/STEC

Answer 40

verotoxin released and it causes inhibition of protein synthesis (which is why it is called shiga like toxin e coli)

Question 41

worst thing you can do in patients with VTEC/STEC and why

Answer 41

treat them with antibiotics because the killed organism will release more toxin causing even more damage

Question 42

what is screened for in routine stool culture? what if it is bloody?

Answer 42

routine - campylobacter, shigella, salmonella | if bloody - STEC/VTEC

Question 43

complication of a pseudopod forming protozoa

Answer 43

entamoeba histolytica | toxic megacolon

Question 44

how does one get infected with balantidum coli

Answer 44

contaminated water or food by pig feces

Question 45

pathogenesis of balantidum coli

Answer 45

you ingest cyst --> becomes trophozoite which invades the SI --> into LI to invade colon --> shed cyst and trophozoite in the feces

Question 46

diagnosis of balantidum coli

Answer 46

ciliated trophozoite in the feces because cysts are not frequent

Question 47

manifestations of ascaris lumbricoides and treatment

Answer 47

asymptomatic --> but could be pulmonary symptoms | treat with albendazole

Question 48

how would you describe the ascaris lumbricoides worm

Answer 48

large white/pink adult worm that is 15-25 cm long

Question 49

clinical manifestation of trichuris trichuria especially in children

Answer 49

asymptomatic with peripheral blood eosinophilia | in children - iron deficiency and growth retardation

Question 50

treatment of trichuris trichura

Answer 50

albendazole just like ascaris (both are worms that gives you eosinophilia)

Question 51

manifestation of anyclostoma duodenale nectar americanus

Answer 51

iron deficiency and protein energy malnutrition especially in children and women of child bearing age

Question 52

treatment of ancylostoma duodenale nectar americanus

Answer 52

albendazole and iron replacement