Fig. 2.

Antibiotic development pipeline from 2014 to 2019. As of December 2019, a total of 41 antibiotics were in development (15 in Phase 1 clinical trials, 12 in Phase 2, 13 in Phase 3, 1 submitted for FDA application), and 14 approved. It is estimated that only 60% of drugs that enter Phase 3 will be approved for treatment (pewtrusts.org). New antibiotic development involves time and resources and there are very few novel antibiotics under development. The declining number of antibiotics in the development pipeline, in part, reflects the challenges associated with its development. At the same time, bacteria that survives antibiotic treatment are spreading