Microbes have the last word

Many organisms have evolved by interacting with one another through one or more of three mechanisms: commensalism (co‐existence), symbiosis (collaboration) or parasitism (confrontation). Human evolution is no exception; we have evolved in the presence of large numbers of microbes including commensals and symbionts that are vital to our survival. Nevertheless, of all the microbial species inhabiting the biosphere, a small but deadly proportion is pathogenic to humans and animals.Throughout history, infectious diseases in humans have been observed, treated and recorded. More than 100 years ago, Ferdinand Cohn, Louis Pasteur and Robert Koch collectively discovered that microbes—including bacteria, fungi and viruses—are the causative agents of infection. In fact, the period between 1890 and the 1930s, when the main human pathogens were isolated and identified, can be regarded as the golden age of microbiology; finally, the enemy was known.Although these discoveries did not lead to major advances in the treatment of disease, scientists began to develop and use the first crude vaccines against bacterial and viral infections such as typhus, yellow fever, tetanus and diphtheria. Furthermore, a search began in earnest for a ‘magic bullet’ that could cure disease by specifically targeting and killing microbes. This began with the use of chemicals, previously used to stain tissues, to deliver toxins harmful to specific bacteria. In the early 1900s, pioneering research into the use and modification of synthetic chemotherapeutic agents by Paul Ehrlich's laboratory led to the discovery of Salvarsan® (arsphenamine), an anti‐syphilitic agent introduced as the first—albeit unpleasant—antimicrobial therapy.However, until the mid‐1930s, the treatment of bacterial infections was largely empirical and still relied on native and cultural variations of snake oils and elixirs. Nonetheless, an understanding of good patient care developed along with markedly improved public hygiene and sterile procedures. In 1932, Gerhard Domagk synthesized the first active …