Question

14- In a disk diffusion test. A 35 mm zone of inhibition was noted around a disk of impregnated with streptomycin when it was tested against a culture of S.

aureus.However, within the zone of inhibition two colonies with characteristic S. aureusmorphology were noted and upon gram staining the colonies consisted of Grampositive cocci in grape-like clusters. What is your explanation? (1 marks).

Fig: 1