Antibiotic prescribing during an outbreak of meningococcal disease.

During a prolonged outbreak of meningococcal disease caused by serogroup B serotype 15 sulphonamide-resistant strains in one British health district, there was considerable variation in attack rates by town. General practitioner (GP) antibiotic prescribing rates were compared in high and low incidence towns. The only significant difference found was that erythromycin prescribing was more frequent in the high incidence towns (rate ratio 4.0, 95% CI 3.2-4.8, in March 1987 and 3.0, 95% CI 2.4-3.7, in November 1987). This was probably due to increased GP consultation rates for upper respiratory tract infection (URTI), but higher erythromycin usage may have increased meningococcal acquisition rates or susceptibility to meningococcal disease. Antibiotic prescribing rates should be further investigated in defined areas of high and low incidence of meningococcal disease.