Gut bacteria after recovery from COVID-19: a pilot study

OBJECTIVE: COVID-19 has been a major infectious disease lately in hu-mans. 10% of people experience persistent symptoms twelve weeks after having COVID-19. The gut microbiota is essential for host immunity. Thus, gut microbiota composition may contribute to the recovery of COVID-19 patients. The impact of COVID-19 on the gut microbiota of patients during recovery is less explored. We investigated the potential alterations of bacterial gut microbiota of immediately recovered COVID-19 patients, and six months after their recovery. MATERIALS AND METHODS: Stool samples were collected from 8 patients with COVID-19 immediately after their recovery, and six months after SARS-CoV-2 clearance, as well as from 8 healthy donors as a control group. 16S rRNA gene sequencing was performed to analyze the correlation between disease recovery and microbiota using the immediately recovered and control group. Specific primers were designed for the most significantly altered bacteria and used to analyze the changes in intestinal mi-crobiota composition of patients using qPCR. qPCR comparisons were performed on three groups: newly recovered from COVID-19, after six months of COVID-19 recovery, and healthy controls.RESULTS: Compared with the healthy con-trol group, patients who immediately recovered from COVID-19 had significantly less presence of 15 bacterial groups. The immediately recovered patients had a very significantly higher relative abundance of the opportunistic pathogen Mycolicibacterium. No differences were found between the immediately recovered patients, and after six months of recovery using the qP-CR analyses.CONCLUSIONS: Our results contribute novel insights regarding the alteration of human gut microbiota and the emergence of opportunistic pathogens in recovered patients of COVID-19. Further studies with a larger experimental size are needed to reveal balance or dysbiosis in patients after COVID-19 recovery.