Cholera is an important diarrhoeal disease and an important cause of death, particularly during epidemic outbreaks, in Bangladesh and many other developing countries. Used as an adjunct to management of dehydration, antimicrobial therapy using an appropriate agent reduces diarrhoea duration and stool volume in severe cholera by about half.

The usefulness of antimicrobials has, however, been greatly eroded by the increasing prevalence of resistant strains of V. cholerae O1. From October 2004 at the Matlab Hospital and from December 2004 at the Dhaka Hospital of ICDDR, B, V. cholerae strains became increasingly resistant to tetracycline and erythromycin- two drugs used in the treatment of severe cholera in adults and children respectively. Because of this high prevalence of resistance we resorted in early 2005 to using ciprofloxacin for treatment against multi drug resistant V. cholerae. Although all isolates were susceptible to ciprofloxacin when standard thresholds for disc-diffusion or E-test were used, but majority of the strains demonstrated a MIC value of 0.250 µg/ml, over hundred-folds greater than the V. cholerae strains tested in earlier years, which generally had a MIC of <0.003 µg/ml.

In this randomized, double blind, controlled trial we will assess clinical and bacteriological response to 12 hourly oral dose of ciprofloxacin for 3 days in which the first two doses will be 1 g each and the later 4 doses will be 500 mg each, and compare them with a single 1 g oral dose of azithromycin. We are using azithromycin as the comparator drug because current circulating V. cholerae isolates are susceptible (MIC ≤ 0.125 µg/ml) to this azithromycin, and single-dose azithromycin has been evaluated earlier to be effective in the treatment of cholera.