Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) is an infectious virus that causes coronavirus disease 2019 (COVID-19) transmitted mainly through droplets and aerosol affecting the respiratory tract and lungs. Little is known regarding why some individuals are more susceptible than others and develop severe symptoms. In this study, we analyzed the nasopharyngeal microbiota profile of aged patients with COVID-19 (asymptomatic vs. symptomatic) vs. healthy individuals. We examined the nasopharynx swab of 84 aged-matched patients, out of which 27 were negative asymptomatic (NegA), 30 were positive asymptomatic (PA), and 27 patients were positive symptomatic (PSY). Our analysis revealed the presence of abundant Cyanobacterial taxa at phylum level in PA (p-value = 0.0016) and PSY (p-value = 0.00038) patients along with an upward trend in the population of Litoricola, Amylibacter, Balneola, and Aeromonas at the genus level. Furthermore, to know the relationship between the nasal microbiota composition and severity of COVID-19, we compared PA and PSY groups. Our data show that the nasal microbiota of PSY patients was significantly enriched with the signatures of two bacterial taxa: Cutibacterium (p-value = 0.045) and Lentimonas (p-value = 0.007). Furthermore, we also found a significantly lower abundance of five bacterial taxa, namely: Prevotellaceae (p-value = 7 × 10−6), Luminiphilus (p-value = 0.027), Flectobacillus (p-value = 0.027), Comamonas (p-value = 0.048), and Jannaschia (p-value = 0.012) in PSY patients. The dysbiosis of the nasal microbiota in COVID-19 positive patients might have a role in contributing to the severity of COVID-19. The findings of our study show that there is a strong correlation between the composition of the nasal microbiota and COVID-19 severity. Further studies are needed to validate our finding in large-scale samples and to correlate immune response (cytokine Strome) and nasal microbiota to identify underlying mechanisms and develop therapeutic strategies against COVID-19.
Highlights
In little more than three months after the first discovery of the SARS-Cov-2 virus inHubei, Wuhan, China, in the early days of 2020, the virus quickly spread across the globe.The novel nature of COVID-19 has left our immune systems completely vulnerable to disease
It is well documented that certain microorganisms in the nasal microbiota can influence the immune response in patients suffering from respiratory infections [15]
We found surprising results: out of 27 samples from the negative asymptomatic (NegA) group, 2 samples were low reads, and out of 30 samples from the positive asymptomatic (PA) group, 4 samples were low reads, whereas 14 samples from the COVID-19 positive symptomatic (PSY) group were low reads (Table 1)
Summary
In little more than three months after the first discovery of the SARS-Cov-2 virus inHubei, Wuhan, China, in the early days of 2020, the virus quickly spread across the globe.The novel nature of COVID-19 has left our immune systems completely vulnerable to disease. The case fatality rate is orders of magnitude lower than other infectious diseases, such as Ebola and SARS [2,3], the high transmissibility and respiratory nature of the virus are great concerns. The most striking feature of COVID-19 positive patients is the wide clinical spectrum, with the majority remaining asymptomatic or exhibiting mild cold-like symptoms, while others have severe viral pneumonia requiring prolonged hospitalization in intensive care unit stay or resulting in death. Reasons as to why some individuals exhibit mild to severe symptoms, while others are solely asymptomatic, are still unknown. It has been reported that an increase in species richness in an individual’s nasal microbiota is correlated to fewer and less severe symptoms during rhinovirus infections [8,9]
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