COVID-19 infection disrupts gut microbe balance, especially with antibiotics: Study

Acute COVID-19 infection disrupts a healthy balance between good and bad microbes in the gut, especially after antibiotic treatment, according to a study.

The research, published in the journal Molecular Biomedicine, may lead to the development of probiotic supplements to redress any gut imbalances in future patients.

The study, which began in May 2020, was designed to zero in on the microbiome because many COVID-19 sufferers complained of gastrointestinal issues -- both during the acute phases of their illness and while recuperating.

"We wanted to gain a deeper understanding by looking at specimens that would give us an indication about the state of the gut microbiome in people," said Martin Blaser, a professor at Rutgers University in the US, and an author of the study.

"What we found was that, while there were differences between people who had COVID-19 and those who were not ill, the biggest difference from others was seen in those who had been administered antibiotics," Blaser said.

Early in the pandemic, before the introduction of vaccines and other antiviral remedies, it was a common practice to treat COVID-19 patients with a round of antibiotics to attempt to target possible secondary infections, said Blaser.

Humans carry large and diverse populations of microbes which live in the gastrointestinal tract, on the skin and in other organs, with the largest population in the colon.

Scientists have shown over recent decades that the microbiome plays a pivotal role in human health, interacting with metabolism, the immune system and the central nervous system.

The researchers noted that the microbiome has many different functions.

"One is to protect the human body against invading pathogens, whether they are bacteria or viruses or fungi. That goes deep into evolution, maybe a billion years of evolution," Blaser said.

Medical problems often arise when the balance between beneficial and pathogenic microbes in a person's microbiome is thrown off, a condition known as dysbiosis.

The researchers studied microbiomes by measuring populations of microorganisms in stool samples taken from 60 subjects. The study group consisted of 20 COVID-19 patients, 20 healthy donors and 20 COVID-19-recovered subjects.

They found major differences in the population numbers of 55 different species of bacteria when comparing the microbiomes of infected patients with the healthy and recovered patients.

The scientists plan to continue to test and track the microbiomes of patients in the study to ascertain the long-term effect on individual microbiomes from COVID-19.