- Handling of Treatment Failures: If the study treatment is judged to have failed clinically patients will be treated for 3 days with an agent other than azithromycin or ciprofloxacin to which the isolate of V. cholerae will be found to be susceptible to. The treatment code will not be broken for these patients. Patients with microbiological failure will be treated with a suitable drug as determined by antimicrobial susceptibility of such isolates.