The study is focusing on the fashionable topic of "microbiome analysis", which is most likely a fad that won't lead to any breakthrough cures. However, the important finding of the study is that changes of vitamin B1 (thiamine) levels are involved in the pathogenesis of diabetes. Sudden drop in blood thiamine levels can possibly be used as an early biomarker of diabetes I onset.
http://www.nature.com/articles/nmicrobiol2016180
Change in gut bacteria in type 1 diabetes could affect disease development
"...They didn't notice a stark difference in bacterial species between people with and without diabetes, as opposed to what has long been believed by scientists. However, they did see clear differences in what the bacteria did. And in type 1 diabetes, these differences tend to arise when the body's immune system attacks beta cells. By changing thiamine levels, the once beneficial bacteria become a health risk and can worsen the patient's condition. Researchers are yet to determine whether the gut bacteria preferably increased or decreased thiamine levels in that case. Previous studies have suggested that a deficiency of thiamine is more harmful than an increase in the body's thiamine levels. In patients with type 1 and type 2 diabetes, it may increase the risk of developing microvascular complications, like retinopathy, nephropathy and neuropathy, from the effects of high blood sugar. These results have two implications: one is that high dose therapy with thiamine may counter the development of common complications of diabetes associated with a high risk of cardiovascular disease and mortality; the other is that a sudden decrease in thiamine levels may be used as a biomarker in the early stages of type 1 diabetes."
http://www.nature.com/articles/nmicrobiol2016180
Change in gut bacteria in type 1 diabetes could affect disease development
"...They didn't notice a stark difference in bacterial species between people with and without diabetes, as opposed to what has long been believed by scientists. However, they did see clear differences in what the bacteria did. And in type 1 diabetes, these differences tend to arise when the body's immune system attacks beta cells. By changing thiamine levels, the once beneficial bacteria become a health risk and can worsen the patient's condition. Researchers are yet to determine whether the gut bacteria preferably increased or decreased thiamine levels in that case. Previous studies have suggested that a deficiency of thiamine is more harmful than an increase in the body's thiamine levels. In patients with type 1 and type 2 diabetes, it may increase the risk of developing microvascular complications, like retinopathy, nephropathy and neuropathy, from the effects of high blood sugar. These results have two implications: one is that high dose therapy with thiamine may counter the development of common complications of diabetes associated with a high risk of cardiovascular disease and mortality; the other is that a sudden decrease in thiamine levels may be used as a biomarker in the early stages of type 1 diabetes."