 Developing new antibiotics is especially challenging. Firstly, the cost of developing a new antibiotics has been estimated to be at about $1.5 billion US. On the other hand, the revenue is only about $50 million annually. And that has really driven away very large pharmaceutical companies who have been traditionally discovering and marketing new antibiotics. So now the responsibility for antibiotic discovery lies on academic scientists as well as small and middle-sized enterprises who tend to be less well-funded. And lastly, the issue is that it takes maybe perhaps one or two decades for new antibiotics to be discovered and then proved through various phases of clinical trials and finally to clinical practice.