S. pneumoniae MDR phenotypes by patient age group in the United States in 2000-2002. Phenotype 1 was resistance to penicillin, azithromycin, and SXT; phenotype 2 was resistance to penicillin, ceftriaxone, azithromycin, and SXT; and phenotype 3 was resistance to penicillin, ceftriaxone, and SXT.