Treatment of chancroid with spectinomycin or co-trimoxazole.

Chancroid, the third most prevalent venereal disease in Thailand, was treated with a single 2-gm dose of spectinomycin, or two tablets of co-trimoxazole (trimethoprim-sulfamethoxazole) twice daily for seven days. The differences in cure rates between the two groups were statistically significant. The chancroidal ulcers were cured in 93.7% of 175 patients treated with spectinomycin, and in 48.2% of 168 co-trimoxazole-treated patients (P less than 0.01). The in vitro susceptibility of Haemophilus ducreyi to spectinomycin was 4 to 16 micrograms/ml and to co-trimoxazole 32 micrograms/ml or higher. Thus we found that a single-dose regimen of spectinomycin was significantly more effective than the standard seven-day regimen of co-trimoxazole for the treatment of chancroid.