Chapter 27, Problem 3S

Use of multiple antibiotics is not a bad idea if ill of the bacteria are killed. In the case of sane persistent infections, this is an effective strategy. However, it does provide very strong selective pressure for rare genetic events that procure multiple resistances in a single bacterial species. For this reason, it is not a good idea for it be the normal practice The more bacteria that undergo this election for multiple resistance, the more likely a will arise. This is helped by patients not taking their entire course of antibiotic because bacteria may survive by chance and proliferate, with each generation providing the opportunity for new mutations. This is also complicated by the horizontal transfer of resistance via resistance plasmids, and by the existence of transposable genetic elements that can move genes from one piece of DMA to another.