There haves been increasing regulatory scrutiny given to the prophylactic use of antibiotic in animals (perhaps later than would have been optimal) http://www.fda.gov/AnimalVeterinary/GuidanceComplianceEnforc...

Some of the biggest challenges in antibiotics are economics not technical e.g., http://emerald.tufts.edu/med/apua/news/news-newsletter-vol-3... The only recent company built on antibiotics (Cubist) was purchased for a revenue stream and its R&D was disassembled by Pharma in the last year or so. You can bet that a good amount of organization knowledge has been lost. There are some start ups out there, but as far as I understand, there is little will to provide of equity or strategic funding for early development programs/companies. With the timelines in this industry, that doesn't bode well for 'breakthroughs' in the near future. With the recent idiocy and avarice of some of the "actors" in the industry (e.g., pharma bro, epi-pen). I am bracing for a backlash on pricing, even on needed products) which would further decrease the economic will for companies/funds to invest in early stage programs. Some comments here tout that the the wonders of science will solve this given time. Maybe so, but it's also possible that the burden of economics (and lowest-common denominator politics) could quench the wonders of science for the near term.