The Akkermania muciniphila may play an important role in the occurrence and development of Prediabetes. The purpose of this study was to evaluate the safety and efficacy of AKK in the treatment of Prediabetes among obese patients. In this study, a single center, randomized, double-blind, placebo-controlled design is adopted. 90 obese subjects with Prediabetes are included in this study, and are allocated to AKK group, BBR group, and placebo group at a ratio of 1:1:1. The study treatment lasts for 12 weeks. The changes of body fat, glucose metabolism, lipid metabolism indicators compared with the baseline at the end of the treatment will be analyzed. In addition, glucagon like peptide-1 (GLP-1) and inflammatory markers (hsCRP、TNF-α、IL-6、IL-8、IL-1β) in blood will be analyzed before and after treatment. The changes in fecal flora structure and the AKK bacteria also will be analyzed.

Inclusion Criteria:

1. Aged 18-65
2. Overweight/obesity (24.0≤BMI≤40.0 kg/m^2)
3. Fasting blood glucose ≥6.1 and <7.0 mmol/L, or 2-hour postprandial blood glucose ≥7.8 and <11.1 mmol/L, or glycosylated hemoglobin ≥5.7% and <6.5%
4. Fertile subjects (including male and female subjects) agreed to take effective contraceptive measures that the investigator accepted during and within 3 months after the trial (e.g. intrauterine device or a condom); the fertile female subjects with serum human chorionic gonadotropin test negative results within 7 days before the investigational product administration; Infertile female must be surgically infertile or at least 1 year after menopause.
5. Subjects should understand the nature, significance, potential benefits, inconvenience and risks of the study before the trial begins, fully understand and voluntarily sign the informed consent.

Exclusion Criteria:

1. Subjects who diagnosed with diabetes mellitus, medical obesity (excluding those who have been off medication for more than 1 year), or other secondary diabetes mellitus (e.g., Cushing's syndrome, thyroid dysfunction, or acromegaly);
2. Subjects who has undergone bariatric surgery;
3. Subjects who has acute or chronic progressive or unstable disease, liver and kidney insufficiency, serious cardiovascular and cerebrovascular diseases;

3.Subjects with acute diabetic complications such as diabetic ketoacidosis or diabetic hypertonic coma within within latest 3 months; 4.Patients with hemolytic anemia or glucose-6-phosphate dehydrogenase deficiency; 5.History of intestinal or intestinal surgery within 1 year, or non-gastrointestinal surgery within 6 months; 6.Excessive alcohol consumption in the last 10 years (more than 30 g/ day for male and 20g/ day for female) 7.Pregnant or lactating subjects 8.Subjects that the investigator considers need to excluded due to other causes.

In order to protect the privacy and security of the subject, the subject data will not be provided to other researchers