Safety and Efficacy of Human Microbiota Transplantation for Overweight and Obese Type 2 Diabetes Mellitus

Inclusion Criteria: * A diagnosis of T2DM (≥2 months) according to the dagnostic and typing criteria of Chinese guideline for type 2 diabetes * Control the blood glucose level through diet or exercise only and never receive any hypoglycemic agent in the last 8 weeks. * Continuous treatment with insulin and its analogues for no more than 14 days in the last year. (The duration of treatment with insulin and its analogues for gestational diabetes mellitus is not included) * 7.0%≤HbA1c≤10.0% * Fasting plasma glucose(FPG)\<15mmol/L * 24kg/m2≤BMI≤35kg/m2 * Give informed consent and agree to receive FMT * Agree to maintain the same diet and exercise habit during the whole process. Exclusion Criteria: 1\. Diagnosed with T1D, gestational diabetes mellitus(GDM) or other special type of diabetes. 2\. The presence of any of the following medical histories or clinical conditions that the investigator believes the risks of participation in the study outweigh the benefits or the treatment of combined conditions that may affect subject compliance or the objectivity of the study outcomes. 1. Patients with gastrointestinal disease(such as Irritable bowel syndrome, inflammatory bowel disease, peptic ulcer, gastrointestinal bleeding history, etc.) or history of gastrointestinal surgery(such as gastrectomy, gastroenterostomy, bowel resection, etc.) and are assessed to be unsuitable to participate in this clinical trial by researchers. 2. Patients with severe diabetic complications (diabetic ketoacidosis, hyperglycemic hyperosmolar condition etc.) in the last 6 months. 3. Patients in unstable condition and need therapy for proliferative diabetic retinopathy or maculopathy, severe diabetic neuropathy, diabetic foot or intermittent claudication in the last 6 months. 4. Patients with severe kidney diseases and liver diseases or systemic diseases of other viscera. 5. History or condition of following heart disease in the last 6 months * Decompensated cardiac insufficiency(graded III or IV in NYHA) * History of unstable angina, myocardial infarction, coronary artery bypass grafting, or coronary stent implantation * Diagnosed with Severe arrhythmias requiring treatment(like long QT syndrome etc.), and assessed to be unsuitable to participate in this clinical trial by researchers 6. Patients with uncontrolled hypertension (systolic blood pressure (SBP) ≥ 160mmHg or diastolic blood pressure (DBP) ≥ 100mmHg at screening time). 7. Diagnosed with hemorrhagic stroke or ischemia stroke in the last 6 months and assessed to be unsuitable to participate in this clinical trial by researchers. 8. History of other severe endocrine system diseases that affect glucose metabolism or body weight, such as multiple endocrine adenomas, acromegaly syndrome, Cushing's syndrome, and hyperthyroidism and assessed to be unsuitable to participate in this clinical trial by researchers. 9. History of malignant tumor in the last 5 years (cured basal cell carcinoma of the skin and carcinoma in situ of the cervix are excluded) or malignant tumor being assessed. 10. Patients who have psychiatric disorders or language disorders or are unable or reluctant to communicate, cooperate and be followed up or may have difficulty completing the study judged by the investigator. 11. Patients with severe infection or trauma or history of major surgery in the last 3 months and assessed to be unsuitable to participate in this clinical trial by researchers. 12. History of substance abuse in the last five years, including repeated and large use of dependent medication which is unrelated to medical purposes (addiction medicine and habitual medicine which can lead to physical and mental dependence are included). 13. HIV, TP and HBsAg positive. 14. Participated in any clinical trials of interventional medication or devices in the last 3 months. 15. Patients with anemia or patients who need regular blood transfusion treatment. 3\. Receive any of the following medications or treatments. 1. Self-reported weight changes of more than 5kg or use of medication which may result in weight-gain or weight-loss including diuretic, weight loss medicine and so on in the last 90 days. 2. Use of antibiotics in the last 12 weeks. 3. Patients who have used drugs that may affect blood glucose for more than 1 week in the last 12 weeks, such as oral/intravenous glucocorticoid growth hormone, estrogen/progesterone, high-dose diuretics, antipsychotic drugs, etc. (usage of low-dose diuretics (hydrochlorothiazide \< 25mg/d, indapamide ≤1.5mg/d) for antihypertensive purposes are not included). 4. Consumption of food or preparation like yogurt, fermented foods, dietary supplements (fish oil, probiotics, prebiotics, various microorganisms, minerals, nutritional foods or herbal preparations) and so on which can affect the gut microbiota in the last 4 weeks. 5. Previous or planned bariatric surgery. 4\. Laboratory results during the screening period meet the following criteria. 1. Alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) \> 2.5 upper limit of normal. 2. Glomerular filtration rate(eGFR)\< 60 mL/min/1.73m2 calculated by CKD-EPI. 3. Hemoglobin \<100g/L 4. Proteinuria 2+ or above. 5\. Patients who have suspected or confirmed history of alcohol or drug abuse. 6\. Patients known to be allergic to the FMT or its accessories. 7\. Pregnancy, breast-feeding, or plans to become pregnant. 8\. Patients who are assessed to be unsuitable to participate in this clinical trial by researchers for other reasons.