Metagenome Analysis of Gut Microbiota in CC Patients

Inclusion Criteria: 1. Chronic constipation according to Rome III criteria; 2. Age ≥ 18 years; 3. BMI: 18.5-25kg/m2; Exclusion Criteria: 1. Bowel constipation due to innate factor (e.g. megacolon) or secondary interventions (e.g. drugs, endocrine, metabolic, neurologic or psychologic disorders); 2. History or evidence of gastrointestinal diseases (e.g. cancer, inflammatory bowel diseases); 3. Previous abdominal surgery, except cholecystectomy, appendicectomy, tubal ligation and cesarean section; 4. Previous proctological or perianal surgery; 5. Rectal prolapse and/or grade 3-4 internal hemorrhoids according to AGA classification; 6. A constipation condition meeting the Rome III criteria for IBS or functional abdominal pain syndrome; 7. Pregnant or breast-feeding women; 8. Infection with enteric pathogen; 9. Usage of probiotics, prebiotics, antibiotics or PPIs within the last month; 10. Smoking or alcohol addiction within the last 3 months; 11. Uncontrolled hepatic, renal, cardiovascular, respiratory or psychiatric disease; 12. Disease or therapy with drugs (e.g. antidepressants, opioid narcotic analgesics, anticholinergics, calcium antagonists, nitrates, antimuscarinics) that, in the opinion of the investigator, could affect intestinal transit and microbiota.