UVA Researchers: Antibiotics Found to Weaken Body's Ability to Fight Off Disease

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University of Virginia School of Medicine (Photo courtesy https://med.virginia.edu) University of Virginia School of Medicine (Photo courtesy https://med.virginia.edu)

New research has found that antibiotics could make the body less effective in fighting off diseases.

The research was conducted by the University of Virginia Health System's infectious diseases department.

The research was conducted on microbiomes, which is bacteria that lives in our intestines.

“We've found that when we give antibiotics, they affect a key white blood cell called a neutrophil, an neutrophils are the cells that kill bacterial infections, so they're very important part of our immune system,” said Chief of Infectious Diseases Dr. Bill Petri. 

Researchers are currently looking for ways to counter the effect of antibiotics weakening the body's ability to fight off diseases. 

This adds another reason for doctors to give antibiotics only when they're absolutely needed. 

Release from the University of Virginia Health System:

CHARLOTTESVILLE, Va., Sept. 5, 2017 – Adding another reason for doctors to avoid the overuse of antibiotics, new research shows that a reduction in the variety of microbes in the gut interferes with the immune system’s ability to fight off disease.

Researchers at the University of Virginia School of Medicine have found that antibiotic use made neutrophils, a type of immune cell, less effective in fighting infections and weakened the intestinal barrier against invading bugs.

“Neutrophils play an important role as a first-line ‘innate immune response’ when foreign pathogens invade,” said researcher Koji Watanabe, PhD. “We found that antibiotic disruption of the natural microbes in the gut prevented this from happening properly, leaving the gut susceptible to severe infection.”

Antibiotics and the Microbiome

The researchers were seeking to understand the role of the gut microbiome – the microorganisms that live within us – in amebic colitis, a potentially deadly parasitic infection common in developing countries.

They analyzed stool samples collected from children in the urban slums of Dhaka, Bangladesh, and determined that children with more severe infections had less diversity in their gut microbiome. (Antibiotic use, the researchers note, is widespread in low- and middle-income countries, with children often getting more than two dozen treatments by age 2.)

The researchers then used lab mice to determine how the decrease in natural intestinal flora might be worsening the disease. They found that antibiotics disrupted the mice’s gut microbiomes, decreasing the activity of neutrophils and blocking these important white blood cells from responding when needed. This left the gut insufficiently protected. In essence, the gut’s guards did not respond when called and the invaders could march right in.

In addition, the intestinal barrier that protects against disease was compromised. The disruption of the microbiome reduced production of a key cellular protein vital to the barrier’s effectiveness.

“I think the take-home is that this is another important reason not to use antibiotics unless they are clearly needed,” said researcher Bill Petri, MD, PhD, the chief of UVA’s Division of Infectious Diseases. “Unwise use of antibiotics not only increases the risk of multi-drug resistant bacteria and the risk of C. difficile infection but also impairs white blood cell function.”

In addition to shedding light on the role of the microbiome in protecting our health, the work could prove important in the efforts to develop a vaccine for amebic colitis, also known as amebiasis. The discovery might offer a way to enhance the effectiveness of such a vaccine, the researchers noted.

Findings Published

The researchers have published their findings in the scientific journal PLOS Pathogens. The team consisted of Watanabe, Carol A. Gilchrist, Md Jashim Uddin, Stacey L. Burgess, Mayuresh Abhyankar, Shannon N. Moonah, Zannatun Noor, Jeffrey R. Donowitz, Brittany N. Schneider, Tuhinur Arju, Emtiaz Ahmed, Mamun Kabir, Masud Alam, Rashidul Haque (who led the Bangladesh efforts), Patcharin Pramoonjago, Borna Mehrad and Petri.

The Bangladesh work represented a collaboration of UVA with icddr,b, a group based in Dhaka dedicated to solving public health problems in low- and middle-income countries through scientific research.

The work was supported by the National Institutes of Health, grant R01 AI026649-28, and the Henske Foundation.