Lab #14: Chemical control of Microorganisms

Define:

Disinfection

Chemical agent used on non-living surfaces

Define:

Antiseptic

Chemical agent used on living surfaces

Name the two different approaches that are useful to evaluate the antibacterial effect of chemical agents

1. Laboratory methods

2. In-Use methods

Purpose of Laboratory methods?

Assess the properties of of chemical agents under laboratory conditions

Purpose of In-Use methods?

Assess the effectiveness of chemical agents in real world settings

What were the two lab procedures used in this lab

1. Tube Dilution procedure

2. Fingertip antisepsis procedure

What was the purpose of the Tube Dilution procedure?

To determine the minimum inhibitory concentration

What’s was the purpose of the Fingertip antisepsis Procedure?

To test the effectiveness of various antiseptics against bacteria on your fingertips

Define:

Minimum Inhibitory Concentration (MIC)

The lowest concentration of a test agent that inhibits visible growth of bacteria

How does sterilization differ from antisepsis and disinfection

• Sterilization is killing all life forms, including spores

• Antisepsis and disinfection reduces the number of most pathogens

For the Fingertip antisepsis procedure, rank-order the three agents based on their effectiveness (most effective to least)

1. Hand sanitizer

2. Betadine

3. Lysol

Fill in the blanks:

1. Lysol is an _______ disinfectant but a______ antiseptic

2. Germ-x and Betadine are ________ disinfectants but ________ antiseptics

1. effective; poor

2. poor; effective

What is the control used in the tube dilution?

Broth w/o chemical agent

How do you find out the MIC?

On the graph look at the last NG (no growth)

What was the control in the Fingertip antisepsis procedure?

Water