Drugs from hidden bugs: their discovery via untapped resources.

The drug discovery process is a starving machine requiring constant feeding with new chemical compounds. Synthetic or natural scaffolds: what are the best sources? While synthetic molecules are rapidly generated by combinatorial chemistry, they show lower chemical diversity than their natural counterparts. A significant fraction of known natural products is issued from microbial secondary metabolism; however, more than 95% of bacterial organisms remain unexploited as a source of active chemical compounds due to their cultivation difficulties.