Most of the antibiotics we use today (beta-lactams) are still the close relatives of the first and best-ever antibiotic, Penicillin G.
They are all still produced, by mold slime, ie naturally : and this will probably always be so.
They are produced almost as bulk chemicals, thousands of tons worth annually, a multi-billion dollar industry that lies at the very foundations of the multi-trillion dollar health industry.
But there is (and was) no international treaty, closely negotiated at the very top level (Lord Halifax and Dean Acheson) , at the height of total war and over an extended period of two years, on the patents and scientific information involved in this crucial production of natural penicillin.