I have a friend who used to work in the 'novel anti-bacterials' section of a Big Pharma company. This section was shut down because the company couldn't make any money selling curative drugs-you sell a few of them, the patient recovers,and doesn't buy any more of them. Emphasis was switched to anti-depressant drugs, creating a future where the physician says ' We cannot cure your illness, but we have some new drugs you can take so that the illness doesn't make you sad...'. They can sell anti-depressants, anti hypertensives, and cholesterol-reducing meds to the same patient for a long time. So methicillin resistant staph aureus (MRSA) and vancomycin resistant enteroccus (VRE) are becoming more common, and free-market economics doesn't do much to encourage research in this direction.

Intentional use by humans of vet drugs is common enough to be a research topic, and many of the vet drugs are made by the same companies on the same assembly lines as the meds labeled for human use.

We probably should not choose to stop talking about this stuff because readers might make bad decisions based upon the discussion. We spend lots of time discussing firearms and edged tools: bad decisions with either will generally be more harmful quicker than ill-advised attempts at self-medication.