Inclusion Criteria:  Written informed consent Stated availability throughout entire study period and willingness to fulfill all details of the protocol Age 18-70 Be in general good health as determined by a screening evaluation within 30 days of the first dose of SBD111 or placebo Willing to comply with protocol and report on compliance and side effects during study period Body Mass Index between 18.5 and 35 kg/m2 Normal cardiovascular parameters, systolic blood pressure ≤ 155 mm Hg, diastolic blood pressure ≤ 95 mm Hg)  Exclusion Criteria:  Are currently taking probiotic or prebiotic supplements, or have taken them in the past 30 days Unwilling to avoid probiotics/prebiotics supplements for the duration of the study Known or suspected allergies to probiotics Received oral or parenteral antibiotics within 3 months of enrollment or prescribed antibiotics on day of enrollment. Major surgery or endoscopy within last 3 months. Subject is a smoker Subject has a history of drug and/or alcohol abuse at the time of enrolment Presence of any of the following: Abnormal vital signs or clinically significant systems abnormalities based on screening questionnaire Indwelling catheter or implanted hardware/prosthetic device or feeding tube Febrile illness (oral temperature >37 degrees Celsius) or one or more episodes of diarrhea within 72 hours of baseline visit (first dose of study drug) Active bowel leak, acute abdomen, colitis, or active GI disease or history of gastric or intestinal dysmotility, slowed transit time, variable small intestinal permeability, pancreatitis, or inflammatory bowel disease History of Hepatitis B or Hepatitis C infections, cirrhosis, or chronic liver disease Underlying structural heart disease or previous history of endocarditis or valve replacement Immunosuppression including HIV positive, solid organ or stem cell transplant recipient, receiving any oral or parenteral immunosuppressive therapy, neutrophil count <500/mm^3, or an anticipated drop in the neutrophil count to <500/mm3 History of cancer excluding non-melanoma skin cancers or cancer more than 10 years ago History of collagen vascular disease Active TB Women only - pregnant, planning on becoming pregnant within the next 2 months, breastfeeding, positive urine pregnancy test during screening or within 24 hours of first dose of study drug.  Screening laboratory tests greater than upper normal limit (ULN) or less than lower normal limit (LLN):  WBCs < LLN or > ULN Neutrophils < 1500/µl (1.5 x109/L) Platelets < 100 x 10³/µl (100 x 109/L) Haemoglobin < 9.0 g/dl (90 g/L)  f. GFR of > 40 mL/minute g. AST > 3 x upper limit of normal h. ALT > 3 x upper limit of normal i. Total Bilirubin > 1.5 x upper limit of normal  Any other condition that in the opinion of the investigator would jeopardize the safety or rights of the volunteer participating in the study or would make it unlikely the volunteer could complete the study.