Lab 9

disinfectant

used on inanimate objects to lower the levels or inhibit microorganisms growth

antiseptic

used on live tissue to inhibit the growth of microoganism

antimicrobial agent

a natural or synthetic substance that kills or inhibits the growth of microorganisms such as bacteria, fungi and algae

antibiotic

made from another organism to prevent or kill growth in another microorganism

narrow spectrum antibiotic

an antibiotic that is only able to kill or inhibit limited species of bacteria

broad spectrum antibiotic

antibiotics that were effective against both gram-positive and gram-negative bacteria

-cidal

killing

-static

lacking movement, action, or change

a disinfectant must ___ the pathogen while in contact with them

kill

list two types of bacterial cells that are more resistant to disinfectants

gram-negative bacteria: Pseudomonas and K. pneumoniae

why is antimicrobial susceptibility testing done?

to determine which antimicrobials will inhibit the growth of the bacteria of fungi causing specific infection

what is the name of the antimicrobial susceptibility test also known as the filter paper disk agar diffusion method?

Kirby-Bauer test

what is in the filter paper disks?

antibiotics

what kind of agar is used?

Mueller-Hinton

what is streaked onto the agar plate?

organism in question

where are the filter paper disks placed?

on the surface of the agar

what happens to the antimicrobial agent in the disk after it contacts the agar?

diffuse into the agar

after incubation, what does one look for on the plates?

the zone of inhibition

what does "R" mean in interpretation? How is it determined?

Resistance- size of the circle- large circle means it is resistant (zone of inhibition)

What does "S" mean in interpretation? How is it determined?

susceptibility- the size of the circle- small means its susceptible

name a narrow spectrum antibiotic

penicillin

name a broad-spectrum antibiotic

ampicillin