New antibiotic compounds with novel mechanisms of action have become essential in response to the recent paradigm of increasingly resistant strains of bacteria. Secondary metabolites (natural products) from bacteria such as Actinobacteria serve as lead compounds for the development of pharmaceutical drugs widely used to fight bacterial, viral and fungal infections, as well as cancer and immune system disorders. Pursuing the cultivation, isolation, and identification of rare non-Streptomyces actinomycetes is necessary for antibiotic drug discovery (Chapter 2). The improvement of natural products-based screening, rather than relying on synthetic sources, has been the aim of current pharmaceutical research and development. Alternative strategies to consider include the identification of potential new antibiotics from commercial crude bacterial fermentations. For example, Enradin® by Intervet/Schering-Plough could contain metabolites other than the major active ingredient presumed to be responsible for its antibacterial action (Chapter 3). In examining the driving forces for novel drug development one cannot ignore the fact that developing and developed worlds have disparate challenges that characterize their fights against infectious diseases. Pharmaceutical companies typically invest in research for diseases that will boost financial returns rather than those diseases that impose the greatest global burden, attributed largely to the developing world. A subset of infectious diseases defined as neglected tropical diseases (NTDs) plague the poorest populations in the world and has not been met with the same attention as infectious diseases directly impacting the developed world. Analyzing the similarities and differences between the developing and
developed worlds in their fight against infectious diseases reveals the necessity for new drug development targets and new strategies for equitable pharmaceutical distribution catering to NTD disparities (Chapter 4).