[Meningococcal disease: are patients carriers of meningococci after treatment with antibiotics?].

The aim of the study was to determine whether patients treated for meningococcal disease carried meningococci in the throat on discharge from hospital. If this were the case, supplementary treatment with e.g. rifampicin would be appropriate. The study comprised 106 patients: 98 patients in whom meningococci had been isolated from cerebrospinal fluid, blood or petechiae and eight patients with clinical signs of meningococcal disease in whom meningococci had been isolated only from tracheal aspirate or throat specimens. In 35% (22/62), meningococci were isolated from throat specimens on admission to hospital. From 20 throat specimens inoculated on 5% horse blood agar only, one meningococcal isolate was recovered (5%). From further 37 specimens inoculated on chocolate agar medium selective for pathogenic Neisseria, 18 meningococcal isolates were recovered (49%). This difference is statistically significant (p = 0.001). Meningococci were not isolated from any throat specimens taken on discharge from hospital; 90% (47/52) of these specimens were examined using selective chocolate agar medium. From an observed carriage rate of zero out of 47 it can be judged that the carrier rate does not exceed 6.4% (95% confidence limit). From these results, we conclude that it is unlikely that patients, who have been treated for meningococcal disease, are the source of infection in secondary cases.