Primary aim (clinical outcomes): Descriptive statistics of the clinical outcomes, such as mean and median number of days of symptom duration, primary cure rate, percentage of subjects with resolution of diarrhea, abdominal pain, fatigue, etc will be calculated. Standard deviations and/or confidence intervals will be provided where appropriate. If statistical power allows, multivariate logistic regression models may be used to identify patient-level risk factors predictive of primary cure (such as sex, age, independent-living status, etc.).