Between polymyxin and cetrimide antibiotics,which is more effective?How were you able to tell?

Question

Between polymyxin and cetrimide antibiotics,which is more effective?How were you able to tell?

Answer 1

To tell the difference in effectiveness of one antibiotic over another you need to perform an MIC (minimal inhibitory concentration) assay.  Grow your organism (bacteria/fungi) in 2-fold serial dilutions of the antibiotics.  The lowest concentration that inhibits the growth of your organism is the MIC for that antibiotic.  The results will be very different for different organisms, so you need to test each organism individually to determine which compound has the lowest MIC and would therefore be the most effective.