Although our understanding of pneumonia dates back thousands of years to when symptoms were recognized by Hippocrates, the first typical bacterial pathogen responsible for causing community-acquired pneumonia (CAP), Streptococcus pneumoniae, was not isolated until the late 19th century. Another half a century passed before 3 atypical bacteria were discovered as pneumonia pathogens (ie, Mycoplasma pneumoniae in 1944, Legionella species in 1976, and Chlamydia pneumoniae in 1981). Meanwhile, treatment for CAP only became available in the 1940s with the advent of penicillin followed by cephalosporins. Although macrolides were discovered in the 1950s, newer-generation drugs in this class now commonly used to treat CAP (eg, azithromycin and clarithromycin) were approved by the Food and Drug Administration in the early 1990s. Similarly, although discovered in the 1960s, advanced-generation respiratory fluoroquinolones (eg, levofloxacin, moxifloxacin, and gemifloxacin) were approved between 1996 and 2003.