Table 3.

Analysis of gut microbiota in coronavirus disease 2019 patients in different cohorts

SI. No.	Cohort composition	No of Patients	Demographics of the study populations	Country	Significant gut microbiota found	Study conclusion	Reference
1	A pilot study with 15 healthy individuals (controls) and 15 patients with COVID-19	15	Study performed with hospitalised patients (median age 55 years), Chinese ethnicity and comorbidities were reported	Hong Kong	Abundance of Clostridium hathewayi, Clostridium ramosum, Coprobacillus, which are correlated with COVID-19 severity	Change in the fecal microbiome of COVID-19 patients during hospitalization, compared to healthy individuals (controls)	[48]
2	The two-hospitals cohort, serial stool samples collected from 27 COVID-19 patients among 100	27	Adults hospitalised Chinese patients, comorbidities were noted	Hong Kong	Faecalibacterium prausnitzii, Eubacteriumrectale and bifidobacteria	Gut microbiome involved in COVID-19 severity	[38]
3	United States cohort (majority African American)	50	Studied patients (mean age 62.3 years) were hospitalised with comorbidities, American ethnicity	United States	Some of the significant genera (Corynebacterium Peptoniphilus, Campylobacter, etc.)	No significant associations found between the composition microbiome and disease severity from COVID-19 patient gut microbiota	[50]
4	The study used 53 COVID-19 patients and 76 healthy individuals. 81 fecal samples collected during hospitalization	53	Adults Chinase hospitalised patients, no such comorbidities were noted	China	Elevated gut microbes such as Rothia mucilaginosa, Granulicatella spp, etc.	COVID-19 infection linked with change of the microbiome in COVID-19 patients	[137]
5	15 patients Cohort	15	Study performed adults hospitalised patients with comorbidities, Chinese ethnicity	Hong Kong	Elevated bacterial species Collinsella tanakaei, Collinsella aerofaciens, Morganella morganii, Streptococcus infantis	The study found fecal viral (SARS-CoV-2) activity	[54]
6	Two-hospital cohort with a total of 100 patients. Stool samples collected from 27 patients	27	Hospitalised adults patients were from China, comorbidities were noted	Hong Kong	Several gut microbiota such as Faecalibacterium prausnitzii, Eubacterium rectale, and bifidobacteria	Gut microbiota associated disease severity and inflammation in COVID-19 patients	[38]
7	98 COVID-19 patients (3 asymptomatic, 34 moderate, 53 mild, 3 critical, 5 severe), serial fecal samples collected from 37 COVID-19 patients	37	Adults (mean age 37 years) patients, hospitalised condition from Chinese ethnicity, comorbidities were reported	Hong Kong	A total of 10 virus species in fecal matter (9 DNA virus species and 1 RNA virus, pepper chlorotic spot virus)	Analysis of gut virome (RNA and DNA virome) in COVID-19 patients	[47]
8	Study of fecal samples from 30 COVID-19 patients	30	Patients (mean age 46 years) were hospitalised from Chinese groups, comorbidities were noted	Hong Kong	Increased proportions of fungal pathogens (Candida albicans, Candida auris, Aspergillus flavus, Aspergillus niger) in fecal samples	Analysis of fecal fungal microbiome of COVID-19 patients	[48]

COVID-19: Coronavirus disease 2019.