Relatedness of penicillin-resistant Streptococcus pneumoniae serogroup 9 strains from France and Spain

1 Laboratoire de Microbiologie et Génétique Moléculaire CNRS and Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse, France 2 Centre National de Référence des Pneumocoques, Centre Hospitalo-universitaire, 40 avenue de Créteil, 94010 Créteil, France ABSTRACT Summary: Pulsed-field gel electrophoresis of the genomic DNA of penicillin-resistant strains of Streptococcus pneumoniae was carried out. Eleven clinical strains of serogroup 9 from different French towns and Paris hospitals were tested. The restriction enzymes Apal and Smal were used to digest intact chromosomes, and the fragments were resolved by field-inversion gel electrophoresis (FIGE). Five strains were similar using Apal and Smal . Four others were closely related when using Apal , and five others were closely related when using Smal . These results suggest that 10 of these strains are genetically related and have a clonal origin. The profile of the eleventh strain was completely different. Thus, in a given serotype the spreading of penicillin resistance can result from both clonal and independent events. Five strains had similar FIGE profiles to strains first isolated in Spain, suggesting that a resistant strain had spread from Spain to France. 5 Author for corresprespondence: Anne-Marie Gasc. Tel: +33 61 33 59 71. Fax: +33 61 33 58 86. e-mail: Gasc@ibcg.biotoul.fr Keywords: Streptococcus pneumoniae, fingerprinting, FIGE, penicillin resistance, serotype