title: Clonal expansion of the macrolide resistant ST386 within pneumococcal serotype 6C in France.
abstract: In France, the use of the 7-valent pneumococcal conjugate vaccine (PCV7) lead to an overall significant decrease in PCV7 invasive pneumococcal disease (IPD) incidence. However, the decrease in vaccine serotype prevalence was partially counterbalanced by the serotype replacement phenomenon. In this study, we analyzed the role of the newly described serotype 6C as one of the replacement serotypes. This work was conducted on a large time scale from the early PCV7 era (2002-2003) to the PCV13 era (2010-2011), both on IPD strains recovered from the whole population and nasopharyngeal colonizing strains isolated in infant less than two years, who are known to be the main reservoir for pneumococci. Serotype 6C took advantage over 6A and 6B serotypes, which both decreased over time. A continuous and significant increase in 6C IPD was observed in adults along the study period; in contrast, in children less than two years, only an increase in 6C nasopharyngeal carriage was found, the prevalence of serotype 6C in IPD remaining very low over time. Among 101 6C invasive and colonizing strains studied by MLST, 24 STs were found to be related to three major clonal complexes, CC395, CC176, and CC315. STs related to CC176 tend to disappear after 2009 and were essentially replaced by ST386 (CC315), which dramatically increased over time. This clonal expansion may be explained by the erythromycin and tetracycline resistances associated with this clone. Finally, the decrease observed in nasopharyngeal 6C carriage since 2010, likely related to the PCV13 introduction in the French immunization schedule, is expected to lead to a decrease in 6C IPD in adults thereafter.
authors.affiliation: Centre National de Référence des Pneumocoques (CNRP), AP-HP Hôpital Européen Georges-Pompidou, Paris, France; Département de Microbiologie, Faculté de Pharmacie EA4043, Châtenay-Malabry, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Janoir
authors.affiliation: Département de Microbiologie, Centre Hospitalier Intercommunal de Créteil, Créteil, France; Centre de Recherche Clinique, Centre Hospitalier Intercommunal de Créteil, Créteil, France; Association Clinique Thérapeutique Infantile du Val de Marne (ACTIV), Saint-Maur-des-Fossés, France; Groupe de Pathologie Infectieuse Pédiatrique (GPIP), Paris, France.
authors.forename: Robert
authors.initials: R
authors.lastname: Cohen
authors.affiliation: Centre de Recherche Clinique, Centre Hospitalier Intercommunal de Créteil, Créteil, France; Association Clinique Thérapeutique Infantile du Val de Marne (ACTIV), Saint-Maur-des-Fossés, France; Groupe de Pathologie Infectieuse Pédiatrique (GPIP), Paris, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Levy
authors.affiliation: Groupe de Pathologie Infectieuse Pédiatrique (GPIP), Paris, France; Département de Microbiologie, Université Denis-Diderot-Paris 7, AP-HP Hôpital Robert-Debré, Paris, France.
authors.forename: Edouard
authors.initials: E
authors.lastname: Bingen
authors.affiliation: Département de Maladies Infectieuses, Institut de Veille Sanitaire, Saint-Maurice, France.
authors.forename: Agnès
authors.initials: A
authors.lastname: Lepoutre
authors.affiliation: Centre National de Référence des Pneumocoques (CNRP), AP-HP Hôpital Européen Georges-Pompidou, Paris, France; Laboratoire de Microbiologie, AP-HP Hôpital Européen Georges-Pompidou, Paris, France; INSERM, U872, Paris, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Gutmann
authors.affiliation: Centre National de Référence des Pneumocoques (CNRP), AP-HP Hôpital Européen Georges-Pompidou, Paris, France; Laboratoire de Microbiologie, AP-HP Hôpital Européen Georges-Pompidou, Paris, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Varon
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D002353:Carrier State; D002648:Child; D002675:Child, Preschool; D002999:Clone Cells; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D004917:Erythromycin / Q000627:therapeutic use; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D011008:Pneumococcal Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage*; D065288:Serogroup; D013296:Streptococcus pneumoniae / Q000276:immunology* / Q000472:pathogenicity; D013752:Tetracycline / Q000627:therapeutic use; D018074:Vaccines, Conjugate
chemical_list: D000900:Anti-Bacterial Agents; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate; D004917:Erythromycin; D013752:Tetracycline