The aim of this research proposal is to introduce and test the efficacy of intervention strategies by which the prevalence of resistant strains of Streptococcus pneumonia colonizing children attending Decks could be reduced. Since this paediatric flora is the major reservoir of these dangerous pathogens it is expected that a successful intervention at the level of the ecological reservoir will also have major impact on the prevalence of pneumococcal infections by resistant strains both in paediatric and adult disease. Five centres each located in a different country will carry out the interventions and strain collections. Four additional collaborating units will assist as reference centres for the harmonization of methods in clinical microbiology; molecular epidemiology of drug resistance genes and clones; data management and mathematical modelling (including risk assessment) of epidemiological aspects of EURIS.