Erythromycin test

Purpose

Erythromycin test disks are used to distinguish between E. carotovora (not sensitive to erythromycin) and E. chrysanthemi (erythromycin-sensitive).

Materials

• Erythromycin susceptibility test disks, 15 mcg
• Kings medium B

Instructions

1. Flood KB plate with 1 ml or less of bacterial suspension
2. Allow the plate to dry in a sterile hood for 1 hour
3. Place 1-3 erythromycin susceptibility test disks(15 mcg) disks on each plate
4. Incubate overnight at 27°C

Expected results

• The bacterial isolate is sensitive to erythromycin if a clear zone of no growth occurs around the disk.

Contributed by

From the Virginia Polytechnic Institute and State University Mediabook; contributed by Mary Ann Hansen.