The Nuremberg Code was drafted in 1947 following the appalling revelations of human experimentation committed in Nazi concentration camps. The overarching goal of the Code was to establish a set of rules for the ethical conduct of research using human subjects, guaranteeing that the rights and welfare of such participants would be protected. Two important principles guide and define this Code: the concept of voluntary, informed consent and that no experiment shall be conducted in which “there is an a priori reason to believe that death or disabling injury will occur.”
Just four short years later, the government of the United States would violate the Code as it undertook one of the largest human experiments in history, spraying the city of San Francisco with a microbe, Serratia marcescens, in a simulated germ warfare attack.
The genus Serratia are a group of soil and water-dwelling microbes with one very neat party trick: the manufacture of a red pigment known as “prodigiosin,” derived from the Latin prodigiosus for its marvelous and seemingly supernatural coloring; this color ranges from a lurid vermillion to a washed-out pink depending upon the microbe’s age. This unique property has been regularly exploited in microbiology as a biological marker, tracking metabolic behavior and transmission of bacteria in various environments. For this reason, the microbe is an ideal tool for such work, a showy microbe that naturally flies a very noticeable red flag.
The origins of Serratia are, despite the microbe’s technical laboratory applications, often quite prosaic. The bacteria thrives in wet environments and may be seen forming pink streaks on the insides of shower curtains and along toilet bowls in the homes (surely not mine or yours) of the sanitationally challenged.
