Lab 4: Salmonella

Question 1

How was salmonella first observed?, who discovered it?

Answer 1

Salmonella was first visualized as the pathogen that caused typhoid fever by Karl Ebertts. Salmonella enterica serotype typhi bacteria and salmonella paratyphi (weaker pathogen) was linked to this. It was first discovered by Theobold Smith and named after Daniel Salmon the head of the microbiology department.

Question 2

What are the characterisitics of salmonella?

Answer 2

1. Motile
2. Gram negative
3. Rod shaped
4. Two species: enterica and bongeri
5. 2500 serotypes
6. Facultive anaerobe
7. Causes typhoid and non typhoid fever
8. Can grow in:
   -High acid content
   -High salt concentration
   -Low amount of free water
   -

Question 3

Typhoid fever

Answer 3

Fever caused by salmonella invading the blood stream other organs which can cause septic shock or condition where not enough oxygen is delivered to organs (Consumed by salmonella?).

Question 4

How does salmonella impact people yearly

Answer 4

1) 19,000 hospitalizations

2) 1.5 million deaths

Question 5

True or false there is a zero tolerance policy for salmonella in foods

Answer 5

true

Question 6

What are the characteristics of salmonella foodbourne infection?

Answer 6

takes about 12 to 48 hours for colonization to occur and symptoms to appear
lasts for 4-7 days

Question 7

How is salmonella/salmonellosis spread?

Answer 7

From person to person
Animal to person
Animal to vector to person

Question 8

What are the three types of media salmonella are grown in?

Answer 8

1. Heikteric media
   - Green colored
   - Salmonella appears bluish green with a black dot on it
   - Contains ferrous aluminum and sodium thiosulfate
2. Bismuth sulfide media
   - pale or sandy in color (beige)
   - Salmonella colonies indicated by black colored lead precipitate
   - contains ferrous sulfate: FeSo4
3. XLT4 agar
   - colored red
   - contain yellow and red colored organisams with a black center
   - Contians ferrous ammonium and sodiumthiosulfate

Question 9

Describe the biochemistry behind salmonella appearence on petri dishes?

Answer 9

Salmonella produces H2S which when combined with petri dish agar produces a black colored lead precipitate

Question 10

What was the purpose of the experiment?

Answer 10

To isolate salmonella from a homogenized raw chicken sample

Question 11

What were the materials used?

Answer 11

1. peptone water
2. Heketin, bismuth sulfite, and XLT4 agar
3. Raw chicken

Question 12

Describe Procedure:

Answer 12

1. collect 25 grams of raw chicken and place it in 100ml of peptone water and homogenize it for 2 minuites.
2. Take loop and remove some of it sample and streak 3 plates with it.
3. Incubate samples at 37 degrees celsius for 24 hours.
4. Be sure to remove gloves after you complete procuedure.