Compositions and methods for treating clostridium infection and preventing recurrence of infection

C. difficile infection (CDI) is the most common cause of antibiotic-associated diarrhea. Unfortunately, antibiotic therapy remains as the standard treatment for this antibiotic-induced disease and relapses are common. Antibiotic treatment typically is given for 10 to 14 days for initial or second episode of CDI. For recurrent episodes, more prolonged courses are recommended. It is disclosed herein that lower dose or shorter course of the antimicrobial treatment is sufficient to treat the disease and prevent recurrent disease by enabling a good immunologic response to infection, and perhaps also by better preserving normal flora, thus protecting against relapses or reinfection.