What sort of problem is antibiotic resistance?

Smart bugs: Each antibiotic has a specific mechanism to attach bacteria. When bacteria change their own structure they can escape this mechanism, meaning antibiotic will not work any more. Once bacteria change, their "offspring" will also escape the action of antibiotic. This is now a new strain of bacteria which requires application of different mechanism antibiotic. For some we dont have antibiotics yet!

Big problem: When an antibiotic is given, susceptible bacteria die but any bacteria that have the ability to survive the antibiotic survive and then multiply so the bacteria that are left, cannot be killed by that antibiotic. The bacteria that are left are thus resistant to that antibiotic.