The media, even the FDA, has been reporting the decline in the effectiveness of antibiotics but most of these reports have not done a good job at revealing why scientists think this is happening. Here's a link to a good article on the current understanding of the action of pharmaceutical antibiotics and how they work against good health.. Click Here.
To summarize, the positive action of an antibiotic is to destroy the bacterial cell wall thus causing it to die. There are a couple of "side effects" of this action including the destruction of beneficial bacteria in the body which perform positive functions such as keeping candida and yeast/fungal infections at bay and general support of the body's immune system. In addition, the destruction of the bacterial cell wall seems to initiate a toxic reaction that is also harmful to the body.
More research is needed to understand the antibiotic process but in the meantime, limited use of antibiotics, use of alternative/natural immune support products, and the use of probiotics (to replenish the body's beneficial bugs) after the use of antibiotics may keep your body healthier.