Lab 10 - API System

Enterobacteria are Gram-__, and are shaped like __.

negative; rods (bacillus)

Enterobacteria are either __ or gain access to via the ingestion of __.

endogenous; contaminated food/water

Enterobacteria are susceptible to…

common physical and chemical agents.

Enterobacteria are resistant to __.

low temperatures

Enterobacteria family members (6)

1. Escherichia

2. Salmonella

3. Klebsella

4. Shigella

5. Enterobacter

6. Proteus

Enterobacteria: Escherichia example

E. coli

Enterobacteria: Salmonella example

S. typhimurium

Enterobacteria: Klebsiella example

K. pneumoniae

Enterobacteria: Shigella example

S. dysenteriae

Enterobacteria: Enterobacter example

E. aeorgenes

Enterobacteria: Proteus example

P. vulgaris

Analytical Profile Index (API) System

plastic strip of 20 microtubules with dehydrated medium in the bottom and an upper cupule

Multi-test, a system that…

incorporates several media in a single unit

Muti-test system Advantages (4)

1. minimal storage space

2. less media used

3. rapid results

4. computerised

API-20E is ideal for __ bacteria.

Gram-negative

Enterotube II Advantages (2)

• easy to use

• quickest set up

Enterotube II Disadvantages (3)

1. smaller test capacity 12 vs 20

2. less accurate

3. more expensive

API System Advantages (4)

1. higher accuracy

2. more flexible

3. standardised

4. easy to interpret

API System Disadvantages (2)

• additional steps

• less convenient inoculation

All compartments in the API-20E System receive…

bacterial saline solution

The listed reactions use ___ to create an anaerobic environment.

1. Arginine dehydrogenase ADH

2. Lisine Carboxylase

3. Ornithine carboxylase

4. Urea hydrolysis

sterile mineral oil

Positive sterile mineral oil reactions are __, while negative ones are __.

• red/orange (+)

• yellow (-)

Citrate Utilisation (CIT) reaction is positive when __ and negative when __.

• blue-green/blue (+)

• pale green/yellow (-)

Sodium Pyruvate (VP) reaction which test for acetoin production is positive when __, and negative when __.

• pink/red (+)

• colourless (-)

Charcoal gelatin (GEL) reaction which tests for gelatinase is positive when __, and negative when __.

• diffusion of black (+)

• NO diffusion of black (-)

With computerised analysis, the first positive reaction has a value of __, second positive reaction has a value of __, and the third positive reaction has a value of __.

• 1

• 2

• 4

Computerised analysis produces a 7-digit number that is associated with the organism’s…

analytical profile index (API)

Example: What is the 7-digit number associated with organism’s API?

- - -|- + +|+ + +|- + +|- - -|- + -|+ -

0676021 - P. vulgaris

Example: What is the 7-digit number associated with organism’s API?

+ - +|+ - -|- - +|- - +|+ - +|+ + +|- +

5144572 - E. coli