Clinical trial of ampicillin v. trimethoprim-sulphamethoxazole in the treatment of Shigella dysentery.

Following a nationwide outbreak of Shigella dysentery type 1 and the recognition of Shigella isolates resistant to ampicillin, the drug of choice, we conducted a clinical trial to compare the efficacy of ampicillin v. trimethoprim-sulphamethoxazole for the treatment of Shigella dysentery. Patients with symptoms of dysentery and no other complicating illness were randomized into one of two treatment groups. Patients in the two groups were comparable at the time of hospital admission with regard to age, sex, presenting complaints and Shigella strains. They responded well with both regimens and there was no significant difference in the mean time until stool became culture negative (1.4 days), temperatures returned to normal (2.7 days) and faecal leucocytes disappeared (3.0 days); abdominal pain, tenesmus and stool blood and mucus improved significantly more rapidly with trimethoprim-sulphamethoxazole than with ampicillin. There was no evidence of toxicity with either drug. While both drugs are effective for the treatment of Shigella dysentery, trimethoprim-sulphamethoxazole was considered to be superior.