BIOD 171 LAB 5 NOTE
Title: GE05 Testing bacteria for antibiotic sensitivity
Objective: to determine the threshold of antibiotic sensitivity across bacterial
strains using the Kirby-Bauer method (aka standardized disc susceptibility
test)
Procedure:
1. Streak bacteria A across an LB agar plate for confluent growth using
a sterile L spreader
2. Evenly place the paper antibiotic discs on the plate
3. Invert the plate and incubate at 37C
overnight Notes:
Materials needed: non-selective agar plate, bacterial cultures growing in
liquid media, L spreader, antibiotic disc,
Bacteria A- measure the zones of inhibition and see if bacteria are
susceptible to antibiotics or if they
The white zone is susceptible to bacteria being killed. Bacteria resistant to
disc
Penicillin- measure in millimetres- 36mm across; some time zones overlap to
get accurate reading measure radius.
Results:
List the diameter of the zone of inhibition for
each disc Reference chart to determine
sensitivity level: Resistant >
intermediate>susceptible
Title: GE05 Testing bacteria for antibiotic sensitivity
Objective: to determine the threshold of antibiotic sensitivity across bacterial
strains using the Kirby-Bauer method (aka standardized disc susceptibility
test)
Procedure:
1. Streak bacteria A across an LB agar plate for confluent growth using
a sterile L spreader
2. Evenly place the paper antibiotic discs on the plate
3. Invert the plate and incubate at 37C
overnight Notes:
Materials needed: non-selective agar plate, bacterial cultures growing in
liquid media, L spreader, antibiotic disc,
Bacteria A- measure the zones of inhibition and see if bacteria are
susceptible to antibiotics or if they
The white zone is susceptible to bacteria being killed. Bacteria resistant to
disc
Penicillin- measure in millimetres- 36mm across; some time zones overlap to
get accurate reading measure radius.
Results:
List the diameter of the zone of inhibition for
each disc Reference chart to determine
sensitivity level: Resistant >
intermediate>susceptible
