Question
Why a drug remain effective for a group of microbes but not on other type of group?
Solution
Members of a single group have common traits i.e., many biochemical processes inside their cells are similar. As a result, the drug block these biochemical pathway and result in the killing of the microbe. However the different group of microbes do not share the same biochemical pathways and hence the rug has no effect on them. Since the same drug cannot block the different biochemical pathways in different groupps , same drug will not be effective against a microbe belonging to a different group.
