When good gut bacteria get sick

July 11, 2014
When good gut bacteria get sick
Citrobacter rodentium bacterial cells (reddish-brown) reside alongside commensal flora (black rods) in the colon. Credit: Bry laboratory.

Being sick due to an infection can make us feel lousy. But what must the ecosystem of bacteria, or microbiota, colonizing our guts be going through when hit with infection? A study from Brigham and Women's Hospital (BWH) has utilized unique computational models to show how infection can affect bacteria that naturally live in our intestines. The findings may ultimately help clinicians to better treat and prevent gastrointestinal infection and inflammation through a better understanding of the major alterations that occur when foreign bacteria disrupt the gut microbiota.

"Our gut contains ten-times more bacterial cells than there are human cells in our body," said Lynn Bry, MD, PhD, director of the BWH Center for Clinical and Translational Metagenomics, senior study author. "The behavior of these complex bacterial ecosystems when under attack by can have a big impact on our health."

Georg Gerber, MD, PhD, MPH, co-director of the BWH Center for Clinical and Translational Metagenomics, co-first study author, developed novel computer algorithms to analyze the different stages of infection when a pathogen known as Citrobacter rodentium, which causes disease in mice similar to food-poisoning in humans, was introduced into the guts of mice. Bry and her team generated a two-month time-series of the population levels of bacteria throughout multiple sites in the intestine. The computational framework, known as Microbial Counts Trajectories Infinite Mixture Model Engine, developed by Gerber, was used to identify dynamic changes within the complex communities of bacteria in the gut associated with infection and inflammation.

The researchers observed many disruptions in the normal bacteria at different locations in the gut during the infection. For instance, they discovered a microbial signature in the colon involving species belonging to the genus Mucispirillum that showed decreases early in infection before the onset of symptoms. Other signatures included increases in populations of from the Clostridiales and Lactobacillales families occurring after the pathogen had disappeared. Interestingly, some of these signatures occurred in locations in the gut where the pathogen was not directly damaging host cells.

"From a clinical perspective, these new microbial signatures we identified could help clinicians detect early stages of inflammation or subtle persistent disease in patients with gastrointestinal disorders, such as inflammatory bowel disease," said Bry. "Moreover, several time-dependent microbial signatures we identified may be leveraged to conduct further research of other infectious and inflammatory conditions."

The study is published July 11, 2014 in PLOS ONE.

Explore further: More than just bacteria: The importance of microbial diversity in gut health and disease

Related Stories

In the gut, immunity is a two-way street

July 10, 2014

In recent years, it has become increasingly clear that many diseases are triggered or maintained by changes in bacterial communities in the gut. However, the general view up into now has been rather simple: bacteria stimulate ...

Recommended for you

We've all got a blind spot, but it can be shrunk

August 31, 2015

You've probably never noticed, but the human eye includes an unavoidable blind spot. That's because the optic nerve that sends visual signals to the brain must pass through the retina, which creates a hole in that light-sensitive ...

Biologists identify mechanisms of embryonic wound repair

August 31, 2015

It's like something out of a science-fiction movie - time-lapse photography showing how wounds in embryos of fruit flies heal themselves. The images are not only real; they shed light on ways to improve wound recovery in ...

New 'Tissue Velcro' could help repair damaged hearts

August 28, 2015

Engineers at the University of Toronto just made assembling functional heart tissue as easy as fastening your shoes. The team has created a biocompatible scaffold that allows sheets of beating heart cells to snap together ...

Fertilization discovery: Do sperm wield tiny harpoons?

August 26, 2015

Could the sperm harpoon the egg to facilitate fertilization? That's the intriguing possibility raised by the University of Virginia School of Medicine's discovery that a protein within the head of the sperm forms spiky filaments, ...

Research identifies protein that regulates body clock

August 26, 2015

New research into circadian rhythms by researchers at the University of Toronto Mississauga shows that the GRK2 protein plays a major role in regulating the body's internal clock and points the way to remedies for jet lag ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.