Antibacterial use in community practice: assessing quantity, indications and appropriateness, and relationship to the development of antibacterial resistance.

Most use of antibacterials occurs in community practice; however, despite the widespread belief of inappropriate use and the resultant increase in antibacterial resistance, little data exist describing antibacterial use in this setting. A MEDLINE search of English-language articles was conducted for epidemiological studies assessing quantity, indication and appropriateness of antibacterial use in community practice. A 1983 study of international antibacterial use described considerable disparities in quantity of use between countries. Subsequent longitudinal studies from the US, Canada, Australia and the UK described changing patterns of antibacterial use. No increase in the total rate of antibacterial use was reported by any of the 4 countries; however, all countries reported increased use of newer and/or broad-spectrum agents (e.g. fluoroquinolones, amoxicillin-clavulanic acid, cephalosporins and new macrolides] coupled with decreased use of older and/or narrow-spectrum agents [e.g. phenoxymethylpenicillin (penicillin V), erythromycin, ampicillin and tetracycline). Most (approximately three-quarters) use of antibacterials was in the treatment of respiratory tract infections. Prescribing rates for respiratory tract infections of presumed viral aetiology (e.g. the common cold) ranged from 17 to 60% in the UK and US, respectively. Among indications for which antibacterials were indicated, the appropriateness of antibacterial use received little study. Correspondingly, the rates of antibacterial resistance among common respiratory pathogens (Streptococcus pneumoniae and Haemophilus influenzae) have increased significantly in the past decade, although disparities exist between countries. Antibacterial use is considered a major factor in the development of antibacterial resistance, although the relationship between community antibacterial use and resistance has been poorly described. Further study of antibacterial usage patterns and associated resistance patterns is fundamental to the development of methods to reduce unnecessary and inappropriate use, thereby slowing the development of antibacterial resistance in the community.