lab 12

Question 1

What are safe cooking temperatures for the following:
Beef roast/steaks
Fish
Pork
Ground beef
Egg dishes
Chicken (whole or ground)
Turkey (whole or ground)

Answer 1

Beef roast/steaks   145
Fish   145
Pork   145
Ground beef   160
Egg dishes   160
Chicken (whole or ground)   165
Turkey (whole or ground)   165

Question 2

What color is produced for the following:
E. coli - MAC and HE
Salmonella sp. - MAC and HE

Answer 2

E. coli
MAC- beige/pink
HE- orange
Salmonella sp.
MAC- green
HE- beige

Question 3

Define Enterics and other info

Answer 3

Normal flora of the intestines of human and/or animals

• > 90% are obligate anaerobic bacteria
• includes bacteria, fungi, protozoans, etc
• normal flora are predominately non-pathogens
• Enterobactraceae - a bacterial family with many GNB enterics (Salmonelle, Shigella, E. coli, Proteus

Question 4

Name 2 clinical manifestations of GI disease

Answer 4

Diarrhea- mainly watery stools, typically no blood
Dysentery- more severe; often higher volume water stools, mucus, pus, blood
-may include fever, cramps, pain and vomiting

Question 5

True or False

Gastrointestinal disease can consist of infections and/or intoxications

Answer 5

True

Question 6

Name 4 bacterial pathogens (Enterobacteraceae family) of the GI? Gram reactions? Disease type?

Answer 6

Salmonella (animal flora), GNB, infection
Shigella (animal flora), GNB, infection
Escherichia coli (E. coli 0157:H7 is animal flora), GNB, infection
Proteus sp., GNB, infection

Question 7

MacConkey Agar (MAC) plate contents

Answer 7

Selective and Differential for growing many GN’s
Low bile & CV dye- inhibits GP’s
Contains lactose
-lactose fermenters = pink colonies
-non fermenters = colorless or beige colonies

Question 8

What bacteria ferments lactose on a MAC plate?

Answer 8

Escherichia coli
Serratia
Klebsiella

Question 9

What bacteria is a non fermenter on a MAC plate?

Answer 9

Proteus
Salmonella
Shigella

Question 10

Hektoen Enteric (HE) plate contents

Answer 10

Selective and Differential (more selective than MAC)
-used to better isolate more pathogenic enterics
Higher bile and dyes (bromothymol blue, acid fushin)
-inhibits GP and many GN
Contains lactose, sucrose, salicin
-fermenters appear yellow, orange, salmon or pink
-non fermenters appear green/blue
Contains sulfates + iron (like SIM agar)
-sulfide producers form colonies with black centers (H2S)

Question 11

Name 3 bacteria that produce black centers (H2S) on an HE plate

Answer 11

Salmonella sp.
Escherichia coli
Proteus vulgaris

Question 12

What is the expected Gram reaction of a member of the Enterobacteriaceae?

Answer 12

Gram negative

Question 13

What is the oxygen requirements of the family Enterobateriaceae?

Answer 13

Facultative anaerobic

Question 14

What is the oxygen requirements for most of the intestinal enteric bacteria?

Answer 14

Most are obligate anaerobic, some aerobic

Question 15

List 5 genera found in the Enterobacteriaceae

Answer 15

Salmonella
Escherichia coli
Salmonella typhi
Shigella
Proteus sp.

Question 16

Escherichia coli 0157:H7 on HE plate
Gram reaction statement?
HE agar fermentation?
ID
Disease?
Clinical manifestations?
Treatment?

Answer 16

GNB
Fermentor with yellow/orange colonies
10-100 cells
Gastroenteritis, dysentary, hemolytic eremic syndrome, UTI, menigitis, septicemia
Cramping, diarrhea, vomiting, fever
HUS- decreased urination, lethary, decreased kidney function
Supportive only, fluids, electrolytes

Question 17

Shigella sonnei or flexneri on HE plate
Gram reaction statement?
HE agar fermentation?
ID
Disease?
Clinical manifestations?
Treatment?

Answer 17

GNB
Non fermenters, clear colonies. No sulfide produced
10-200 cells
Shigellosis or bacillary dysentery
Bloody diarrhea, fever, cramping
Ampicillin, ceftriazone, trimethoprim-sulfamethoxazole

Question 18

Salmonella enteritis on HE plate
Gram reaction statement?
HE agar fermentation?
ID
Disease?
Clinical manifestations?
Treatment?

Answer 18

GNB
Non fermenter, sulfide producers blue w/ black center
12-20 cells
Salmonellosis, typhoid fever
Fever, ab pain/cramping, diarrhea
Ampicillin, trimethophrim-sulfamethoxazole, ciprofloxin and supportive care, fluids/electrolytes

Question 19

Salmonella typhi on HE plate
Gram reaction statement?
HE agar fermentation?
ID
Disease?
Clinical manifestations?
Treatment?

Answer 19

GNB
Non fermenters, sulfide producer blue w/ black center
1000-10000 cells
Typhoid fever
Weakness, nausea, vomiting, ab pain, high fever, possible ab rash
Ampicillin, trimethophrim-sulfamethoxazole, ciprofloxin and supportive care, fluids/electrolytes