Table 2.

Changes in gut and airway microbiota bacterial species during coronavirus disease 2019

Changes	COVID-19 vs non-COVID-19 patients	Number of patients COVID-19 vs non-COVID-19	Ref.
Gut microbiota	Increase: Ruminococcus gnavus, Ruminococcus torque, Bacteroides dorei	100 vs 78	[20]
	Decrease: Bifidobacterium adolescentis, Faecalibacterium prausnitzii, Eubacterium rectale
	Increase: Streptococcus, Rothia, Veillonella, Actinomyces	30 vs 30	[80]
	Increase: Blautia, Coprococcus, Collinsella	53 vs 76	[81]
	Decrease: Streptococcus, Weissella, Enterococcus, Rothia, Lactobacillus, Actinomyces
	Increase: Bifidobacterium, Bacteroides, Parabacteroides, Escherichia-Shigella	22 vs 40	[82]
	Decrease: Faecalibacterium, Dorea, Enterobacter
	Increase: Corynebacterium, Campylobacter, Klebsiella	50 vs 34	[83]
	Increase: Streptococcus, Clostridium, Lactobacillus, Bifidobacterium	64 vs 40	[84]
	Decrease: Bacteroidetes, Roseburia, Faecalibacterium, Coprococcus, Parabacteroides
Airway microbiota	Increase: Veillonella, Staphylococcus, Corynebacterium, Neisseria, Actinobacillus, Selenomonas	192 vs 95	[85]
	Decrease: Haemophilus, Alloiococcus
	Increase: Lactobacillus fermentum, Lactobacillus reuteri, Lactobacillus delbrueckii, Lactobacillus salivarius	19 vs 23	[86]
	Increase: Corynebacterium_1, Staphylococcus, Dolosigranulum, Peptoniphilus, Lawsonella	38 vs 21	[87]
	Decrease: Leptotrichia, Fusobacterium (especially Fusobacterium periodonticum), Haemophilus	18 vs 12	[88]
	Increase: Propionibacteriaceae	31 vs 9	[89]
	Decrease: Corynebacterium accolens

COVID-19: Coronavirus disease 2019.