Drug-resistant Streptococcus pneumoniae in day-care centres in Stockholm County.

Between January 1994 and July 1995, 40 pre-school children were found to have drug-resistant Streptococcus pneumoniae(DRSP), i.e. reduced sensitivity to penicillin (minimum inhibitory concentration, MIC, > or =0.1) and resistance to at least two other antibiotic drugs. Twenty-five of the children were index cases with symptoms of respiratory disease, and 15 children were carriers discovered in contact-tracing in connection with an index case. Children attending the same group in the day-care centre as an index child were routinely screened. Thirteen of the index children were attending day-care centres. In 11 of these day-care centres, contact-tracing and nasopharyngeal swabs from 424 children and 128 day-care personnel identified an additional 13 asymptomatic children who were carriers of DRSP. In all but one case, the same serotype as the index case was discovered. No day-care personnel were carriers of the DRSP strain. Sixteen (64%) of the 25 children with symptoms caused by DRSP were 1 year old or younger, whereas eight (61%) of the 13 children who were carriers of DRSP were 3-4 years old. In conclusion, when a child attending a day-care centre is discovered to have respiratory disease caused by DRSP, there is a great probability that additional children will be identified in the group with the same DRSP strain.