Note this question is only really applicable to people working in bacteriology departments.

This is a Staphyococcus aureus isolate from a patient presenting with cellulitis.

(The antibiotic disc on the left contains erythromycin and the antibiotic disc on the right contains clindamycin.)

1) What phenomenen is shown here?

2) What is the molecular basis of this phenomenen?

3) What bacterial species can this be present in?

4) What implications does this have for treatment of the patient?

Click here for the answers with brief explanations.

Michael