If I were to break the history of infectious diseases medicine into periods I would say that infectious disease has moved into the period of the microbiome. This period, I believe, will be characterized by major discoveries regarding the role of the microbiome not only in health and disease but also establishing the role of the microbiome and its constituent microbes in various physiological functions in virtually every living organism on the planet.
I have found no better way to understand the full implications of the microbiome than the masterful science journalist's Ed Yong's I Contain Multitudes: The Microbes Within Us and A Grander View of Life.
This book, which is almost impossible to encapsulate because of the plethora of valuable information it contains, is a tour of the world of life with special attention and focus devoted to the role that microbes play in every organism's life. While the role of the microbiome is very well-established with certain human infections such as Clostridium difficile, Yong moves much further than these topics and explores the role of the microbiome in life more generally moving deftly from humans to corals to frogs. Some of the aspects of the book that I found exceptionally fascinating were his detailing of the various roles of the Wolbachia genus of bacteria as well as that of Sodalis.
After finishing Yong's book, I am increasingly thinking that maybe we should stop discussing genomes and microbiomes and move to discussing the holobiome instead for understanding the "multitudes" and how they interact with us and other organisms likely holds many keys to unraveling the myriad mysteries of biology that remain to be solved