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,  Gastroenteritis Escherichia Coli Male or female ages 18-45, inclusive Provide written informed consent before initiation of any study procedures General good health, without (a) significant medical illness, (b) clinically significant physical examination findings, including vitals, as determined by the PI, and (c) screening laboratory values outside the site's normal limits Within 46 days of vaccination, have normal screening laboratories, per Appendix B for white blood cells (WBCs), hemoglobin (Hgb), platelets, absolute neutrophil count (ANC), sodium, potassium, chloride, bicarbonate, blood urea nitrogen (BUN), creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST) Have normal screening laboratories for urine protein Trace protein is acceptable HgbA1C <6.5% at screening. - Demonstrate comprehension of the protocol procedures and knowledge of study by passing a written examination (passing grade is at least 70 percent) Agrees to complete all study visits and procedures 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 using an effective method of birth control (e.g., use hormonal or barrier birth control such as implants, injectables, combined oral contraceptives, some intrauterine devices [IUDs], cervical sponges, diaphragms, condoms with spermicidal agents must have a vasectomized partner) within 2 months of vaccination, or practice abstinence and must agree to continue such precautions during the study and for 30 days after the Day 29 study visit. Male subjects must agree not to father a child for 30 days after the Day 29 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 Agrees not to donate blood to a blood bank for 12 months after receiving the vaccine  Women who are pregnant or lactating or have a positive serum pregnancy test at screening or positive urine pregnancy test prior to vaccination 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 - Palpated heart rate <55 or >100 beats/minute at rest on 2 separate days*; or *If heart rate between 45 and 55, subjects may be enrolled with an EKG that demonstrates normal sinus rhythm and does not document conduction disorders. --Temperature >/= 38.0 degrees C (100.4 degrees F) Symptoms of an acute self-limited illness, including a temperature >/= 38.0 degrees C (100.4 degrees F), such as an upper respiratory infection or gastroenteritis within 7 days of administration of dmLT. - Positive hepatitis C, or HIV serology or positive hepatitis B serology not consistent with prior hepatitis B immunization Have a positive urine drug screen for opiates Subjects who are unwilling or unable to cease smoking for the duration of the overnight stay. - History of antimicrobial treatment in the 2 weeks before administration of dmLT Received previous experimental E. coli, LT, or cholera vaccines or live E. coli or Vibrio cholera challenges; or previous infection with cholera or diarrheagenic E. coli Abnormal routine bowel habits as defined by fewer than three stools per week or more than two 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 three times per week is permitted), or other significant gastrointestinal tract disease