Children (7) matériau (5) Mexique (5) Children (5) Streptococcus pneumoniae (5) Penicillin (5) hôpital (4) distribution (4) Methods (4) Methods (4) antibiotique (3) Nasopharynx (3) Months (3) Susceptibility (3) âge (2) ville (2) Mexico (2) Population (2) Patients (2) Mortality (2) Health (2) Diseases (2) Day care centers (2) Colonization (2) Carriers (2) Age (2) Age (2) Population (2) Patients (2) Risk factors (2)