Dangerous liaisons-our expanding appreciation of microbial synergism [Editorial]

The ancient paradigm that one microorganism causes one infection that has become entrenched within our fundamental understanding of microbiology since the time of Robert Koch is now being repeatedly challenged. For well over a decade now, this dogma has been contested, with expansion in our conceptualization of how microorganisms multiply in situ, often growing in biofilms rather than in the planktonic cultures with which we make our laboratory predictions on how these organisms might respond to various therapeutic interventions. These are often not growing as a pure culture, but instead employ variegated interactions between both similar and unrelated microorganisms within this diverse heterogeneous population. The review by Wolcott and Costerton provides a valuable overview of our current understanding of these polymicrobial communities that has helped our understanding of the challenges of managing infections, particularly those associated with indwelling devices and complex microbial communities [ 1], The application of metagenomic approaches has helped us to unravel some of the intricacies by which these communities recruit further microorganisms and work collectively, utilizing a ‘distributive genome’ to provide a recalcitrant population resistant to their surrounding forces [ 1], Appreciation of these polymicrobial communities and their enhanced abilities to persist, withstanding both host immune interventions and therapeutic strategies, will improve our appreciation of these communities and evaluation of innovative intervention strategies. We are further indebted to the contributions of Bill Costerton, who sadly passed away during the final stages of the preparation of this review.