MAY 03, 2016 06:59 PM PDT

Aerobic respiration helps gut pathogens fluorish

WRITTEN BY: Kerry Evans
Antibiotics cure infections, right? Well, not always. A new study published in Cell Host & Microbe details how antibiotics can select for the growth of pathogenic bacteria in the gut.

Researchers from UC Davis found that antibiotics create a niche within the gut that helps pathogens like Salmonella flourish. Essentially, antibiotics wipe out the “good” bacteria living in the gut. These bacteria help us break down complex carbohydrates in dietary fiber, producing butyrate. Butyrate is taken up by intestinal epithelial cells and used to convert oxygen to carbon dioxide. Without the butyrate-producing bacteria, oxygen escapes into the intestinal lumen, creating an ideal environment for pathogenic Salmonella to grow.

According to study author Andreas Baumler, “Unlike Clostridia and other beneficial microbes in the gut, which grow anaerobically, or in the complete absence of oxygen, Salmonella flourished in the newly created oxygen-rich microenvironment after antibiotic treatment … in essence, antibiotics enabled pathogens in the gut to breathe”.
 
Antibiotics help Salmonella compete with gut flora.
The group showed that Salmonella coupled aerobic and nitrate respiration to grow in the guts of streptomycin-treated mice. They constructed a mutant that lacked the ability to use oxygen and nitrate and found that its fitness was severely compromised - after 4 days of infection, nearly 2,000-fold more wild type Salmonella were recovered compared to the mutant. Interestingly, similar numbers of the wild type and mutant cells were recovered from mice that had not been treated with streptomycin. This suggests that the ability to use oxygen and nitrate for respiration contributed to the so-called “post-antibiotic pathogen expansion”.

Interestingly, a decrease in the number of butyrate-producing bacteria has been linked to inflammatory bowel disease. Butyrate was found to decrease the production of proinflammatory cytokines in the gut by inhibiting the activity of NF-κB. Similarly, one study found that butyrate increased the number of T regulatory cells in the gut, possibly alleviating inflammation. According to study author Hiroshi Ohno, “butyrate is natural and safe as a therapy and in addition to that it is cheap, which could reduce costs for both patients and society”.
 

Sources: UC Davis, Cell Host & Microbe, Gut, Science 2.0
 
About the Author
  • Kerry received a doctorate in microbiology from the University of Arkansas for Medical Sciences.
You May Also Like
OCT 11, 2018
Microbiology
OCT 11, 2018
New Vaccine Protects Against Lassa Fever and Rabies
In Africa, Lassa fever is a significant threat to public health. It is a member of the same family of viruses as Ebola....
NOV 16, 2018
Microbiology
NOV 16, 2018
Testing the Impact of a Low-gluten Diet on Healthy People
Gluten-free diets have exploded in popularity in recent years, even for people who don't have documented food allergies....
DEC 10, 2018
Microbiology
DEC 10, 2018
The 'Deep Biosphere' of the Earth Teems with Life
Deep within the surface of the earth lies a gargantuan amount of carbon in the form of various types of microbial life....
DEC 12, 2018
Cell & Molecular Biology
DEC 12, 2018
Study Shows Why Diets Rich in Red Meat Increase Heart Disease Risk
For decades, we've known that red meat is a risk factor for heart disease. Now, researchers at the Cleveland Clinic know why....
DEC 12, 2018
Immunology
DEC 12, 2018
Switch HIV Infection
A new study highlights the effects of a target gene in HIV latent infection...
DEC 14, 2018
Microbiology
DEC 14, 2018
Investigating Probiotics as a Potential Therapeutic for Bipolar Disorder
Our gastrointestinal system has a special relationship with our brain - they are connected in what's called the gut-brain axis....
Loading Comments...