PFGE of SmaI-digested chromosomal DNA of S. pneumoniae. (A) mef(A)-carrying serotype 14 strains; (B) mef(E)-carrying strains. Lane 1, PNS06; lane 2, PNS07; lane 3, 1514; lane 4, 1711; lane 5, PN67; lane 6, PN151; lane 7, PN83; lane 8, PN98; lane 9, PN88; lane 10, PN137; lane 11, PN165; lane 12, PN17; lane 13, 1044; lane 14, PN138; lane 15, PN139; lane 16, PN92; lane 17, PNS11; lane 18, PN150; lane 19, PN34; lane 20, 713; lanes M, bacteriophage lambda ladder molecular mass marker. See Table 1 for details about the strains.