Lab: Use-Dilution Test

What are the two outcomes of the use-dilution test?

growth: the concentration of disinfectant used was NOT effective in killing bacteria no growth: the concentration of disinfectant used was effective in killing bacteria

Why do we use non porous beads?

if the beads had pores, the bacteria could hide and disinfectant could not reach them

what is a common source epidemic?

infects many people

What does the use-dilution test examine?

How well a disinfectant works against a high concentration of a known microorganism dried onto a non-porous object

What does a chemical have to pass in order to serve as a hospital disinfectant?

Use-Dilution Test

what is a propagated transmission?

disease moves from one person to another

what is an index case?

the first person with the disease

Name some things to consider when choosing a disinfectant?

1. does it have a broad spectrum? (kill a variety) 2. is it compatible to surface 3. is it safe? 4. cost?

what is an epidemic? and what experiment was used to test it?

a sudden and simultaneous outbreak or increase in the number of cases of a disease in a community. hand shaking

How do you control the spread of infectious agents between people in healthcare setting?

disinfectants and antiseptics

Describe the 5 step use-dilution test.

1. sterile NON POROUS objects (glass beads) are placed in broth of a growing bacterial culture and allowed a brief amount of time for contact 2. glass beads are moved to an empty sterile petri plate to air dry so that a bacterial film forms over object 3. glass beads are covered with the dried bacterial film and submerged into a SPECIFIC CONCENTRATION of disinfectant for 10 minutes 4. the glass beads are removed, and placed into a tube of sterile media and incubated over night 5. examine growth next day

What is the difference between and antiseptic and a disinfectant?

disinfectant is a chemical that can destroy most microbes on INANIMATE surfaces, and an antiseptics destroys microbes on LIVING surface

Name two critical points to know before using a disinfectant.

1. what is the optimal CONCENTRATION of the disinfectant to use to kill most microorganisms 2. what is the optimal length of TIME that a disinfectant needs to be in contact with a microorganism before it is destroyed