The reason why antibiotic-resistant strains have been forming and allowed to be a problem is that people have been misusing antibiotics.
A small scale problem is that antibiotics have been used by human patients that would not benefit from them. Other patients have stopped or cut down on using antibiotics when they have started to feel well - but before the strain has been fully eradicated. In some countries, antibiotics have even been available over the counter without prescription.
A large scale problem is the over-used of antibiotics in agriculture. Livestock are given antibiotics in their feed as a precaution, and this is still going on on a large scale in most Western countries.
Antibiotics-resistant strains are widespread, even the norm in many parts of the world.
Seriously, this has to stop! We need to treat this problem seriously. If a resistant strain of bacteria is found on a farm then that farm should be put in quarantine and the stock of animals should be destroyed, like what happened when Mad Cow Disease - but instead this is seen as normal. Diseased eggs and meat are the norm, and I am not talking about third-world countries. I am talking about Western Europe and the USA.