One of the things that irks me about people's obsession with compulsive sterility and the over-reliance on antibiotics, hand sanitizers, and the like is that it completely runs contra to facts and science. Microbes are essential to human life as we know it and to eradicate them would be catastrophic. A new book by Cornell University immunologist Rodney Dietert provides an excellent overview to this topic that is well-worth reading. Many books have been written about the microbiome in the past few years each with its own specific focus. In this book, Professor Dietert's focus is apparent from the title: The Human Superorganism: How the Microbiome is Revolutionizing the Pursuit of a Health Life.
The proposition that humans are best understood as superorganisms -- an intricate combination of human and microbial genes and cells -- is the theme of the book and Professor Dietert concretizes this theme with with a plethora of examples of how dysbiosis impairs health. One of the most intriguing, to me, lines of thought advanced in this book is "The Completed Self Hypothesis." According to this hypothesis, mammals can not flourish with just the mammalian genes they inherit alone and require the addition of a 2nd genome of microbial genes for optimal life. So those who have deficits in this 2nd genome -- via antibiotic use or birth via caesarean section, for example -- are missing a key component required for health and suffer the consequences in immunity that play roles not only in staving off infections but in the development of non-communicable diseases such as obesity, diabetes, and heart disease (among many others). The challenge in the future will be to prevent dysbiosis from occuring and correcting it when it does.
The book is full of evidence outlining the case for this "hypothesis" (which I believe to be essentially true and a full-fledged theory of disease) as well as many interesting anecdotes including the overall genetic contribution Henry VIII made to his daughter Queen Elizabeth I.
I once attended a very important lecture in which the infectious disease doctor of the future was described as a "microbiome specialist". It will be books such as Professor Dietert that will pave the way in redefining the specialty of infectious disease medicine in a manner that is completely consonant with the new science.