Table 1.
Summary of all studies included in this systematic review.
| Author Year Country |
Number Cases Controls |
Mean age Cases Controls |
Female/male Cases Controls |
Sample type | 16S rRNA gene sequencing (including DNA extraction, sequenced region, sequencing platform, analysis platform, referred database) | Indices of microbial diversity | Major findings (compared with control) |
|---|---|---|---|---|---|---|---|
| Cinek [21] 2018 Azerbaijan Jordan Nigeria Sudan |
73 103 |
11.7 (7.8-13.7) 11.3 (8.1-13.7) |
37/33 51/52 |
Fecal samples | PowerSoil DNA Isolation Kit V4 regions Illumina MiSeq platform Qiime Silva database |
Numbers of OTUs Chao1 index ACE index Shannon index Simpson index Fisher index |
↑Escherichia ↓Eubacterium and Roseburia ↓Clostridium clusters IV or XIVa |
| Higuchi [22] 2018 Brazil |
20 28 |
23.1 ± 8.6 25.2 ± 9.8 |
14/6 18/10 |
Stool samples | PowerSoil DNA Isolation Kit V3-V4 regions Illumina MiSeq platform Mothur RDP |
Numbers of OTUs Chao1 index |
↓Bifidobacterium and Roseburia ↑Bacteroides vulgatus, Bacteroides rodentium, Prevotella copri, and Bacteroides xylanisolvens |
| Huang [23] 2018 China |
12 10 |
22.58 ± 2.24 25.10 ± 0.41 |
7/5 5/5 |
Fecal samples | E.Z.N.A. Mag-Bind Soil DNA Kit V3-V4 regions Illumina MiSeq platform Qiime RDP |
Numbers of OTUs Chao index Shannon index Simpson index |
↑Bacteroidetes/Firmicutes ratio ↓Faecalibacterium |
| Leiva-Gea [24] 2018 Spain |
15 13 |
12.56 ± 3.59 12.25 ± 2.92 |
8/7 6/7 |
Fecal samples | QIAamp DNA Stool Mini Kit V2-V3 regions 454 platform Qiime Greengenes database |
Shannon index Chao index |
↓Microbiota diversity ↑Bacteroides, Ruminococcus, Veillonella, Blautia, and Streptococcus ↓Bifidobacterium, Roseburia, Faecalibacterium, and Lachnospira |
| Salamon [25] 2018 Poland |
22 23 |
36 (31-47) 37 (31-48) |
16/6 16/7 |
Fecal samples | Genomic Mini AX Stool Spin V3-V4 regions Illumina MiSeq platform Qiime Greengenes database |
NA | The microbial diversity and/or composition of fecal samples in T1D did not differ significantly from those in controls |
| de Groot [26] 2017 Netherlands |
53 50 |
35 ± 9 36 ± 13 |
25/28 24/26 |
Fecal samples | Bead-beating protocol V1-V2 regions Illumina MiSeq platform Qiime, Canoco 5, R-studio Database not specified |
Shannon index | ↑Bacteriodales, Christensenella, Bifidobacterium, Ruminococcus, Christensenellaceae, and Chloroplast ↓Subdoligranulum, Streptococcus, Barnesiella, Haemophilus, Roseburia, and Rhodospirillales |
| Pellegrini [27] 2017 Italy |
19 16 |
34 (6-65) 38 (10-56) |
9/10 9/7 |
Biopsy samples | mirVana Kit V3-V5 regions 454 platform Qiime Database not specified |
Chao1 index | ↓Proteobacteria and Bacteroidetes ↑Firmicutes ↑Firmicutes/Bacteroidetes ratio ↑Streptococcus ↓Prevotella |
| Stewart [28] 2017 UK |
10 10 |
27 ± 2 27 ± 2 |
0/10 0/10 |
Fecal samples | PowerLyzer™ PowerSoil® DNA Isolation Kit V4 regions Illumina MiSeq platform Mothur Silva database |
Shannon index | No significant difference was reported between the bacterial profiles or the Shannon diversity indices of T1D compared with controls |
| Qi [29] 2016 China |
15 15 |
11.4 ± 3.0 10.5 ± 1.5 |
7/8 7/8 |
Fecal samples | E.Z.N.A.®DNA Kit V3-V4 regions Illumina MiSeq Platform Qiime Silva database |
Shannon index Chao index |
↓Microbiota richness ↑Blautia ↓Haemophilus, Lachnospira, Pasteurellales, Pasteurellaceae, Intestinimonas, Micrococcales, Dialister, and Caulobacterales ↓Intestinimonas |
| Mejia-Leon [30] 2014 Mexico |
21 8 |
12.3 ± 0.64 11 ± 1.04 |
NA | Stool samples | QIAamp DNA Stool Mini Kit V4 regions 454 platform Qiime RDP |
Chao index | ↑Bacteroides ↓Prevotella, Megamonas, and Acidaminococcus |