February 2023

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Health Capsule

COVID-19 Disrupts Gut Microbes

Microbes live all over your body. These include bacteria, fungi, and viruses. People with COVID-19 often have an imbalance in their gut’s microbes. In hospitalized patients, this can lead to serious infections in the blood, called secondary infections. A new study showed that COVID-19 can disrupt the gut’s microbes and allow harmful bacteria into the bloodstream.

The researchers first studied mice infected with SARS-CoV-2, the virus that causes COVID-19. They found that the virus caused changes to the gut lining. Mice with the virus also had fewer types of microbes in their guts.

Next, the team studied the microbes in stool samples from 96 people with COVID-19. In one of every four samples, a single type of bacteria dominated. Some of these bacteria were resistant to antibiotics, which makes them difficult to kill. The people who had infections in their blood tended to have a less diverse mix of microbes in the gut. The type of bacteria found in their blood was also seen in their gut.

Together, these results suggest that SARS-CoV-2 can upset the balance of gut microbes. This allows harmful bacteria to thrive in the gut. It also alters the gut lining to let these bacteria more easily spread from the gut to the bloodstream.

“Now that we have uncovered the source of this bacterial imbalance, physicians can better identify those coronavirus patients most at risk of a secondary bloodstream infection,” says Dr. Ken Cadwell of New York University, who co-led the study with colleague Dr. Jonas Schluter.