Rifampin and minocycline in meningococcal disease.

Military recruits in four companies were given minocycline, rifampin, ampicillin, or placebo for five days. All antibiotics reduced the rate of carriage of Neisseria meningitidis during treatment, but the effect was significantly more prolonged with minocycline and rifampin. The only difference between these two drugs lay in the isolation of rifampin-resistant meningococci from 17 recruits who received that antibiotic. No isolates were found to be resistant to minocycline. During an outbreak of meningococcal disease among military recruits, minocycline (100 mg every 12 hr) was administered to 8,721 trainees for five days. No new cases of meningococcal disease occurred for the next four weeks. Six new cases then developed among recruits who had begun their training after the initial course of treatment. A second cycle of minocycline, followed in one week by administration of group C polysaccharide vaccine, terminated the outbreak.