Serotype 19A variants of the Spanish serotype 23F multiresistant clone of Streptococcus pneumoniae

Multiply-antibiotic-resistant isolates of serogroup 19 Streptococcus pneumo niae, possessing altered penicillin-binding protein (PBP) 1A, 2B, and 2X ge nes that are indistinguishable from those of the Spanish multiresistant ser ogroup 23F clone, are now commonly encountered in Spain. Those isolates tha t have been serotyped express type 19F capsular polysaccharide. Serotyping of further isolates, and hybridization using a serotype 19F-specific probe, has shown that some of them are serotype 19A, rather than 19F, The Spanish multiresistant serotype 19A, 19F, and 23F multiresistant strains were all shown to be very closely related in overall genotype, as they were indistin guishable by REP-PCR and by the sequencing of internal fragments of three h ouse-keeping genes. The serotype 19A multiresistant strains, like the serot ype 19F multiresistant strains, therefore appear to be a serotype variant o f the Spanish multiresistant serotype 23F clone, which presumably has arise n by recombination at the capsular locus.