How to test whether the resisitant mutant is due to the existence of efflux pump?

I have screened a useful compound, which can inhibit the growth of Staphylococcus aureus and Streptococcus penumoniae at 5 ug/ml. And I have selected a reisistant Streptococcus pneumoniae mutant...

11 January 2013 7,655 7 View