Carriage of internationally spread clones of Streptococcus pneumoniae withunusual drug resistance patterns in children attending day care centers inLisbon, Portugal

Over half (259/503) of drug-resistant (DR) pneumococci colonizing healthy c hildren attending day care centers in Lisbon were identified by molecular t yping methods as representatives of several internationally spread clones. These included the 2 penicillin-resistant pandemic Spanish/USA and French/S panish clones (21% of all DR pneumococci) and 5 new lineages with unusual a ntibiotypes (accounting for an additional 30% of all DR pneumococci), The m ost characteristic feature of the latter group was the high frequency of re sistance to macrolides and tetracycline and very low or no resistance to pe nicillin. These observations provide support for the notion that the nasoph aryngeal flora of children in day care centers may be a global reservoir of worldwide prevalent strains of DR pneumococci.