Table 1.

Altered composition of the gut microbiota in humans with RA.

Author (year)	Increased bacteria	Decreased bacteria	Technology	Reference
Alpizar-Rodriguez et al. (2019)	Prevotellaceae, Prevotella spp.		16S rRNA sequencing	[56]
Chen et al. (2016)	Collinsella aerofaciens and Eggerthella lenta	Faecalibacterium	16S ribosomal DNA	[57]
Chiang et al. (2019)	Verrucomicrobia, Akkermansia		16S rRNA sequencing	[58]
Eerola et al. (1994)		Anaerobic bacteria: Bacteroides, Prevotella, and Porphyromonas	Gas-liquid chromatography of bacterial CFAs	[59]
Kishikawa et al. (2019)	Prevotella		Whole-genome shotgun	[60]
Liu et al. (2013)	Lactobacillus		Quantitative real-time PCR	[61]
Lee et al. (2019)	Lactobacilli, Prevotella	Bacteroides, Bifidobacterium, Bacteroidetes/Firmicutes	16S rRNA sequencing	[62]
Muñiz Pedrogo et al. (2019)	Clostridiaceae		Metagenomic shotgun sequencing	[63]
Maeda et al. (2016)	Prevotella (Prevotella copri)	Bacteroides	16S rRNA sequencing	[39]
Rodrigues et al. (2019)	Bacteroides, Prevotella	Clostridium leptum	qPCR	[64]
Shinebaum et al. (1987)	Clostridium perfringens, coliform		Estimation of bacterial counts in fecal culture	[65]
Sun et al. (2019)	Bacteroides, Escherichia-Shigella	Lactobacillus, Alloprevotella, Enterobacter, Odoribacter	16S rRNA sequencing	[66]
Scher et al. (2013)	Prevotella (Prevotella copri)	Bacteroides	16S rRNA sequencing	[67]
Vaahtovuo et al. (2008)		Bacteroides-Porphyromonas-Prevotella, Bacteroides fragilis, Eubacterium rectale-Clostridium coccoides	Flow cytometry,16S rRNA hybridization, and DNA staining	[68]
Zhang et al. (2015)	Lactobacillus salivarius	Haemophilus spp.	Metagenomic shotgun sequencing	[69]