New Study Finds Link Between Gut Fungi and Severe COVID-19 Cases
A new study published in Nature Immunology has found evidence suggesting that severe cases of COVID-19 may be related to specific fungal bugs in the gut microbiome. The study adds to the growing body of research highlighting the important role of the gut microbiome in health and disease, particularly in relation to human physiology, metabolism, and immune function.
The researchers examined the fungal organisms in the gut microbiome, known as the fungal microbiota or mycobiota, and their potential relationship with COVID-19. They compared patients with and without COVID-19, analyzing the levels of certain fungal organisms in samples from their gastrointestinal tracts. The study included 66 people with severe COVID-19, 25 with moderate COVID-19, and 36 without COVID-19.
The researchers detected a higher amount of fungal organisms in patients with COVID-19 compared to the control group. Antibodies specific to certain fungi were also found to be elevated in the blood of COVID-19 patients, indicating an immune response to these fungal organisms. Two specific fungi, Candida species and S. cerevisiae, were particularly linked to disease severity.
To further investigate the impact of these fungal species on immune responses, the researchers conducted experiments on mice. They colonized older mice with Candida strains isolated from COVID-19 patients and found that these mice exhibited a distinct immune response compared to mice that were not given the Candida fungus. This included an increase in immune cells called neutrophils and other markers of inflammation, including in the lungs.
Some of these immune response changes were partially resolved with anti-fungal treatment or other specific anti-inflammatory medications that have shown benefit in COVID-19 patients.
While this study provides valuable insights into the connection between the mycobiota and severe COVID-19 cases, it does have some limitations. The number of human participants was relatively low, and the study was conducted in 2020 during the first wave of COVID-19 infections. More research is needed to confirm these findings and explore potential interventions based on the mycobiota.
The composition of the microbiome, including the mycobiota, is influenced by various factors, including diet, lifestyle, medical conditions, and treatments such as antibiotics. At present, there are fewer proposed interventions for influencing the mycobiota compared to gut bacteria. However, studies like this one highlighting the importance of fungal bugs in the gut will hopefully stimulate further research in this area.
It is worth noting that the findings of this study may not apply to the current COVID-19 landscape, as the study was conducted during the early stages of the pandemic. With the virus evolving and vaccination efforts underway, more research is vital to fully understand the role of the mycobiota in COVID-19 and its potential implications for treatment and prevention.
Source: The Conversation