Table 1.

Summary of bacteria studied in association with T1D

Bacteria	Gram-positive or -negative	Mode of action	Protection from or acceleration of T1D	References
SFB (Segmented filamentous bacteria), Candidatus Arthromitus	positive	Induce Th17 response	Protection No effect	38 27
Lactobacillus johnsonii & L. reuteri	positive	Healthy probiotics	Protection	39, 81
Klebsiella pneumoniae	negative	Pathogen causing pneumonia	Protection	41
Bifidobacterium	positive	Often as healthy probiotics	Acceleration	67–69
Streptococcus	positive	Some pathogens, some commensal bacteria in mouth, skin, intestine and upper respiratory tract	Protection	40, 82
Akkermansia muciniphila	negative	Mucin-degrading, often anti-inflammatory effect	Protection	52, 90
Bacteroides	negative	processing complex molecules to simpler compounds in the host intestine	Acceleration	89, 90
Leptotrichia goodfellowii	negative	Oral commensal, pathogen in immune compromised patients	Acceleration in NY8.3 NOD	46