EFFECT OF ANTIMICROBIAL USE AND OTHER RISK-FACTORS ON ANTIMICROBIAL RESISTANCE IN PNEUMOCOCCI

Penicillin-resistant and multi-resistant pneumococci have spread globa lly and reached high prevalence in many countries. Antimicrobial use i s considered a major driving force for resistance, although the influe nce in the community has not been as clearly demonstrated. Other risk factors may be important, and only with a clear understanding of the r isk factors can effective control measures be introduced. The main hab itat of the pneumococcus is the nasopharynx of children. Carriage incr eases from birth and is maximal at pre-school age. Antimicrobial use i n children is likely to have a significant influence on the susceptibi lity of pneumococci. Most studies looking for risk factors for resista nce in pneumococci have identified antimicrobial use as a risk factor, especially the following aspects: ongoing, recent, repeated, frequent , and prophylactic antibiotic use. The effect of individual classes of antimicrobials has not been studied in detail but use of p-lactam ant ibiotics and trimethoprim-sulpha has been associated with increased ri sk. Other risk factors are young age, nosocomial acquisition, prior ho spitalization, and HIV infection. Day-care centers can facilitate the spread of resistant pneumococci and an Icelandic study showed that car riage of resistant pneumococci was associated with young age, domicile in an area with high antimicrobial consumption, recent antimicrobial use, frequent antimicrobial use, and use of trimethoprim-sulpha. The r apid increase of penicillin-resistant pneumococci in Iceland was met w ith propaganda against overuse of antimicrobials, which lead to reduct ion of antimicrobial use and subsequently a reduced incidence of penic illin-resistant pneumococci. This reduction may be related to reduced antimicrobial use. Reducing antimicrobial use should be considered imp ortant for programs aimed at reducing antimicrobial resistance.