Antibiotics from Soil
A recent (January 7, 2015) article in the New York Times, "New Antibiotic Stirs Hope Against Resistant Bacteria" is interesting. I recommend that this article be read in combination with an earlier (September 11, 201) NYT article entitled "Mining for Antibiotics, Right under Our Noses."  For further reading,  there is an excellent book entitled "Launching the Antibiotic Era" edited by Carol L. Moberg and Zanvil A Cohn (Rockefeller University Press, 1990) which contains an excellent article by Rollin Hotchiss describing the early work on the isolation of antibiotics from soli.   In addition, Julius  H. Conner, Jr. has written an article describing the work of Selman Waksman in the discovery of streptomycin from a bacteria isolated from soil ("Pay Dirt: The Story of Streptomycin, American Review of Respiratory Disease 117, 773-781, 1978).  Before the days of QSAR and CADD,  when someone from a drug company traveled, they were given tubes to collect dirt for analysis after return.    As one can see both from both Conner and Hotchkiss, the path from dirt to drug is challenging but as the recent  NYT article shows, it can still be useful.