Patient description: A 17 year old boy complains of vomiting, non-bloody diarrhea, abdominal pain, fever, chills and loss of appetite for the past 3 days. He ate a salad at a restaurant prior to his diarrhea onset. Physical exam was remarkable for pallor, jaundice, and diffuse abdominal tenderness. Lab results were as follows: Hemoglobin: 9.7 g/dL Platelet: 110,000 /cu.mm Creatinine: 3.6 mg/dL blood urea nitrogen (BUN): 73 mg/dL direct bilirubin: 2.4 mg/dL lactate dehydrogenase (LDH): 881 IU/L (normal: 110-265 IU/L) Peripheral blood smear showed a moderate number of schistocytes and helmet cells. Shiga-like toxin-producing E. coli (STEC) stx1/stx2 were found in stools. He has no other underlying disease and he is not on any medications.

Clinical trial eligibility criteria: eligible ages (years): 18.0-45.0,  Diarrhea, Infantile Provide written informed consent before initiation of any study procedures Healthy as judged by the Principal Investigator (PI) and determined by medical history, physical examination, and medication history Within 15 days of vaccination, have normal screening laboratories for white blood cells (WBC), hemoglobin (Hgb), platelets, absolute neutrophil count (ANC), sodium, potassium, chloride, bicarbonate, blood urea nitrogen (BUN), creatinine, alanine aminotransferase (ALT), C-reactive protein (CRP) Demonstrate comprehension of the protocol procedures and knowledge of study by passing a written examination (passing grade is at least 80 percent) Capable of understanding, consenting and complying with the entire study protocol Female subjects must be of non-childbearing potential, (as defined as surgically sterile or postmenopausal for more than 1 year), or if of childbearing potential must be practicing abstinence or using an effective licensed method of birth control (e.g., history of hysterectomy or tubal ligation; use hormonal or barrier birth control such as implants, injectables, combined oral contraceptives, some intrauterine devices (IUDs), cervical sponges, diaphragms, condoms with spermicidal agents, or must have a vasectomized partner) within 2 months of infection and must agree to continue such precautions during the study and for 30 days after the Day 56 study visit. Male subjects must agree not to father a child for 90 days after the Day 28 study visit. A woman is eligible if she is monogamous with a vasectomized male Agrees not to participate in another clinical trial during the study period  Women who are pregnant or lactating or have a positive serum pregnancy test at screening or positive urine pregnancy test upon admission to inpatient facility Abnormal Vital signs, defined as Hypertension (systolic blood pressure >140 mm Hg or diastolic blood pressure >90 mm Hg) at rest on 2 separate days; or (heart rate <55 at rest on 2 separate days) Respiratory rate >17 Temperature >/= 38.0 C (100.4 F) or symptoms of an acute self-limited illness such as an upper respiratory infection or gastroenteritis within 7 days of inoculum Active positive Hepatitis B, C, and Human Immunodeficiency Virus (HIV) serologies History of antimicrobial treatment in the 2 weeks before bacterial inoculum Received previous experimental E. coli, LT, or cholera vaccines or live E. coli or Vibrio cholerae challenges; or previous infection with cholera or diarrheagenic E. coli Abnormal bowel habits as defined by fewer than 3 stools per week or more than 2 stools per day in the past 6 months History of chronic gastrointestinal illness, including severe dyspepsia (mild or moderate heartburn or epigastric pain occurring no more than 3 times per week is permitted), lactose intolerance, or other significant gastrointestinal tract disease