title: Comparative epidemiology of Streptococcus pyogenes emm-types causing invasive and noninvasive infections in French children by use of high-resolution melting-polymerase chain reaction.
abstract: BACKGROUND
  This study aims to analyze the epidemiology of Group A streptococci (GAS) emm-types causing invasive and noninvasive infections in French children.
  
  
  METHODS
  From September 2009 to May 2011, we analyzed GAS isolates from 585 pharyngitis, 125 invasive infections and, for the first time in France, 32 healthy carriers. M protein gene (emm) typing of the isolates was carried out by a new rapid technique, combining 3 multiplex-polymerase chain reactions (PCRs) coupled to high-resolution melting (HRM) curves, able to detect 13 major emm-types (emm 1, 3, 4, 6, 11, 12, 22, 28, 75, 77, 87, 89 and 102).
  
  
  RESULTS
  GAS belonging to emm-type 1 were more frequently found among invasive infections than among pharyngitis (24.0% vs. 11.5%, P < 0.001); emm 4 and 89 were more common in pharyngitis than in invasive infections (emm-type 4, 17.4% vs. 6.4%, P = 0.002 and emm-type 89, 9.9% vs. 2.4%, P = 0.006, respectively) and emm 3 and 4 were more common in cases of pharyngitis associated with scarlet fever (21.6% vs. 6.0%, P < 0.001 and 29.3% vs. 14.5%, P < 0.001, respectively).
  
  
  CONCLUSIONS
  HRM method enables the rapid emm-typing of a large number of isolates in epidemiological studies. Comparison of GAS causing invasive and noninvasive infections in the same population of children displays an unbalanced repartition of emm-types.
authors.affiliation: From the *IAME, UMR 1137, INSERM, †Univ Paris Diderot, Sorbonne Paris Cité, ‡Assistance Publique-Hôpitaux de Paris, Laboratoire de Microbiologie, Hôpital Robert-Debré, Paris, France; §Association Clinique et Thérapeutique du Val-de-Marne (ACTIV), Saint-Maur-des Fossés, ¶CRC, Centre Hospitalier de Créteil, Créteil, France.
authors.forename: Camille
authors.initials: C
authors.lastname: d'Humières
authors.forename: Philippe
authors.initials: P
authors.lastname: Bidet
authors.forename: Corinne
authors.initials: C
authors.lastname: Levy
authors.forename: Stéphane
authors.initials: S
authors.lastname: Béchet
authors.forename: Stéphane
authors.initials: S
authors.lastname: Bonacorsi
authors.forename: Edouard
authors.initials: E
authors.lastname: Bingen
authors.forename: Robert
authors.initials: R
authors.lastname: Cohen
mesh_terms: D000293:Adolescent; D000942:Antigens, Bacterial / Q000235:genetics*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005602:France / Q000453:epidemiology; D005838:Genotype; D060005:Genotyping Techniques; D006801:Humans; D008297:Male; D017720:Molecular Epidemiology; D016133:Polymerase Chain Reaction; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D044366:Transition Temperature
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; C014689:streptococcal M protein