The study led by Dr. Pauline Scanlan of APC Microbiome Ireland a Research Ireland centre at University College Cork along with Professors Fernando Baquero from Madrid and Bruce Levin from Atlanta explores the idea of short-sighted evolution. This theory suggests that some microbes harm their hosts as an unintended consequence of their own evolution. Within-host evolution of these microbes may result in what is called niche expansion such that microbes expand into areas of the body they don’t normally inhabit causing illness or even death. However by doing so they often cut off their ability to spread to new hosts leading to what researchers call an evolutionary dead end.

The research highlights examples of gut microbes such as certain strains of E. coli that are implicated in conditions like Crohn’s Disease and others which can cause urinary tract infections and sepsis. The scientists propose that these microbes evolve within the body in a manner that is consistent with the short-sighted evolution theory and provide observational examples to support this idea.

The team’s paper discusses how future research could test their ideas using advanced genetic data and animal studies. They also outline how such experiments might reveal mutations and genetic traits that make microbes more harmful providing new insights for scientists studying the genetic basis of virulence and infectious diseases.

Dr Scanlan was keen to emphasise how the current conceptual and experimental framework in microbiome research takes a largely static view of microbial functionality. Her hope is that the hypothesis presented in this paper will highlight the importance of rapid within-host evolution to microbiome research and in doing so will help change how scientists and clinicians think about and study the functionality of different species of microbes that can inhabit the guts of humans and also non-human hosts.

Source: https://www.ucc.ie/en/apc/news/apc-news/apc-research-offers-fresh-insights-on-why-microbes-harm-their-hosts.html