Curr Biol. Author manuscript; available in PMC 2010 Jun 9.

Published in final edited form as:

Curr Biol. 2009 Jun 9; 19(11): R437–R441.

doi: 10.1016/j.cub.2009.04.001

Selman Waksman first used the word antibiotic as a noun in 1941 to describe any small molecule made by a microbe that antagonizes the growth of other microbes. From 1945–1955 the development of penicillin, which is produced by a fungus, along with streptomycin, chloramphenicol, and tetracycline, which are produced by soil bacteria, ushered in the antibiotic age (Figure 1). Today, the evolution of antibiotic resistance by important human pathogens has rendered these original antibiotics and most of their successors largely ineffective, and if replacements are not found, the golden age of antibiotics will soon come to an end.