1887 TO 2015. “Koch’s postulates never anticipated the era of the human metagenome in which thousands of difficult or impossible-to-culture species of bacteria contribute to a single disease state. Koch’s century-old ideas have held science back from understanding how chronic disease occurs because they make no provision for these facts … mounting evidence that Koch’s postulates no longer apply to discerning the vast amounts of microbes in the human body.”
http://mpkb.org/home/pathogenesis/kochs_postulates