Outpatient use of erythromycin: link to increased erythromycin resistance in group A streptococci.

Resistance to erythromycin in group A streptococci has become an important problem among outpatients in Finland. The prevention of such problems requires information about the relationship between antimicrobial consumption and antimicrobial resistance. Having found considerable variation among health authority areas in the proportions of group A streptococci resistant to erythromycin, we investigated the potential impact of local differences in the consumption of this agent on the development of resistance.