Lab 35- Evaluation of Antiseptics: The Filter Paper Disk Method

Disinfectants

Chemical agents that are applied to inanimate objects such as floors, walls, and tabletops to kill microorganisms.

Step 3

Place the disk on spot one label on the agar side up of the outside of the agar plate

Step 1

Wipe forceps with alcohol wipe to disinfect

Bacteriocidal

agents that kill bacteria

Sanitizers

agents that reduce microbial numbers to a safe level but do not completely eliminate all microbes

Zone of inhibition

degree of sensitivity of bacteria to a drug

What do we do in this lab?

measure the relative effectiveness of various disinfectants and antiseptics against Staphylococcus aureus and Pseudomonas aeruginosa

The larger the zone what?

more effective

Bacteriostatic

only inhibits the growth of bacterial cells but does not kill them

Step 2

pick up one disk with forceps and dip into a disinfectant/antiseptics

Step 4

repeat step 1 through 3 four more times

Sterilants or sporocides

some disinfectants are classified as this because they destroy all microbial life, including endospores Example: Ethylene oxide

Antiseptics

substances such as alcohol or butadine that inhibit microbial growth or kill microorganisms and are gentle enough to be applied to living tissue.