Small Group: Enteric Infections

Question 1

1. Name (including genus) the four most common causes of bacterial enteric disease in the US.

Answer 1

Campylobacter, Echerichia, Salmonella, Shigella

Question 2

2. Distinguish diarrhea from dysentery.

Answer 2

diarrhea- watery stool

dysentery- bloody or purulent stool (likely with Shigellla, EHEC, Salmonella)

Question 3

3. Recognize the one most common source of infection for each organism (Campylobacter, Echerichia, Salmonella and Shigella).

Answer 3

Campylobacter: poultry, dairy, puppies
Echerichia: ground beef, water
Salmonella: poultry (increased by large number of birds kept together also slaughter and automated processing)
Shigella: humans (day care)

Question 4

1. Identify which risk factors are the most important in determining the etiology of a bacterial enteric disease

Answer 4

travel, type of food, food prep/ where food was eaten, sicknesses in close contacts; description of associated diarrhea (watery, pus, blood) and accompanying fever

Question 5

2. Correlate salient signs, symptoms and or conditions with the four most common agents of the bacterial enteric infections in the US.

Answer 5

Camplyobacter: curved gram neg rods, WBC found in feces
Shigella- dysenteric diarrhea, locally invasive, rarely to the blood
Salmonella: malodorus stool (produce H2S)

Question 6

3. Outline a reasonable therapeutic approach for common bacteria causing enteric disease.

Answer 6

hydration and symptom management (supportive care)

Shigella: rehydration, sometimes antibiotics (shorten spread) TMP/sulfa, azithomycin, ceftiraxone and quinolones; anti diaherreals should be avoided

Question 7

4. Identify the usual sources of infection for the four most common bacterial diarrhea causing enteric disease.

Answer 7

Campylobacter: poultry, dairy, puppies
Echerichia: ground beef, water, unpaturized milks and cheese, anything contaminated by cow poop (alfalfa sprouts)
Salmonella: poultry, eggs, reptiles, unpasturized milks and cider, beef
Shigella: humans (day care), contaminated water and food

Question 8

1. Name the usual incubation period and clinical symptoms for staphylococcal food poisoning,

Answer 8

2-4 hours following ingestion of pre-formed toxin, symptoms lasting 24 hours

Question 9

2. Name the virulence factor directly responsible for Staph food poisoning.

Answer 9

production of preformed toxin (enterotoxin) that is heat stable

Question 10

3. List the most commonly contaminated food items associated with staph food poisoning.

Answer 10

ham, potato salad, custard filled pastries, mayo

Question 11

1. Discuss how staphylococcus typically contaminates food. Note other bacteria know for food intoxication by toxin formation.

Answer 11

from the hands of an infected carrier while preparing food

growth of bacteria and formation of toxin while bacteria is at room temps
C. perfiringens is associated with reheated meat dishes with gravy

Note B. cereus (endospore) is associated with reheated fried rice

Question 12

2. Discuss treatment options for someone with staph food poisoning.

Answer 12

supportive care, course is very short and antibiotics do not effect preformed enterotoxins
plenty fluids, anti-nausea meds, young and elderly may need IV fluids

Question 13

3. Describe how staph food poisoning can be prevented.

Answer 13

proper hand handling, not allow Staph to form toxin (refrigeration) , store cooked food in a wide shallow container and refrigerate as soon as possible
keep those with staph away from food prep, prevent contamination (eye or nose infection)

Question 14

1. Name the etiologic agent of typhoid fever.

Answer 14

Salmonella typhi

Question 15

2. List he main signs and symptoms typical of typhoid fever (in case).

Answer 15

high fever to start, belly tenderness and headache
rose spots
hepatosplenomegaly
systemic spread- sepsis

history of travel

Question 16

3. List the two main clinical specimens used to diagnosis typhoid fever.

Answer 16

blood culture (first)
stool culture (later)

Question 17

1. Outline the steps in transmission and pathogenesis of typoid fever form ingestion to complications to carrier state.

Answer 17

S. typhoid invades pyres patches in the illium, gets into blood and stays in gallbladder, which can result in a constant carrier state or reinfect the bowel leading to complication in the bowel by further infection

Question 18

2. Correlate the specimens used to diagnosis typhoid fever and when they should be ordered.

Answer 18

first couple weeks blood, post 3 weeks in stool, later also possibly kidney and in the bone marrow