title: Highly virulent M1 Streptococcus pyogenes isolates resistant to clindamycin.
abstract: BACKGROUND
  Emm1-type group A Streptococcus (GAS), or Streptococcus pyogenes, is mostly responsible for invasive infections such as necrotizing fasciitis (NF) and streptococcal toxic shock syndrome (STSS). The recommended treatment of severe invasive GAS infections is a combination of clindamycin and penicillin. Until 2012, almost all emm1 isolates were susceptible to clindamycin.
  
  
  OBJECTIVE
  We aimed to identify the phenotypic and genotypic characteristics of emm1 GAS clone resistant to clindamycin.
  
  
  METHODS
  GAS strains were characterized by emm sequence typing, detection of genes encoding pyrogenic exotoxins or superantigens. Cluster analysis was performed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Antibiotic susceptibility was assessed using disk diffusion and resistance genes were detected by PCR.
  
  
  RESULTS
  A total of 1321 GAS invasive isolates were analyzed between January 2011 and December 2012. The overall number of invasive isolates resistant to clindamycin was 52 (3.9%); seven of them were emm1 isolates. All isolates had the same genomic markers: macrolide resistance due to the presence of the erm(B) gene, emm subtype 1.0, the same toxin or superantigen profile, PFGE pattern and sequence type.
  
  
  CONCLUSIONS
  This is the first description of highly virulent GAS emm1 isolates resistant to clindamycin in France. This article strengthens the need for monitoring the epidemiology of invasive GAS strains as they could lead to changes in treatment guidelines.
authors.affiliation: Service de bactériologie, centre national de référence des streptocoques, groupe hospitalier universitaire Paris, centre Cochin-Hôtel Dieu-Broca, Assistance publique-Hôpitaux de Paris, Paris, France; Institut Cochin, université Sorbonne Paris Descartes, Paris, France; Inserm, U1016, Paris, France; CNRS (UMR 8104), Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Plainvert
authors.affiliation: Laboratoire de bactériologie-virologie-hygiène, centre hospitalier universitaire de Limoges, 87042 Limoges cedex, France.
authors.forename: C
authors.initials: C
authors.lastname: Martin
authors.affiliation: Service de bactériologie, centre national de référence des streptocoques, groupe hospitalier universitaire Paris, centre Cochin-Hôtel Dieu-Broca, Assistance publique-Hôpitaux de Paris, Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Loubinoux
authors.affiliation: Service de bactériologie, centre national de référence des streptocoques, groupe hospitalier universitaire Paris, centre Cochin-Hôtel Dieu-Broca, Assistance publique-Hôpitaux de Paris, Paris, France.
authors.forename: G
authors.initials: G
authors.lastname: Touak
authors.affiliation: Service de bactériologie, centre national de référence des streptocoques, groupe hospitalier universitaire Paris, centre Cochin-Hôtel Dieu-Broca, Assistance publique-Hôpitaux de Paris, Paris, France.
authors.forename: N
authors.initials: N
authors.lastname: Dmytruk
authors.affiliation: Service de bactériologie, centre national de référence des streptocoques, groupe hospitalier universitaire Paris, centre Cochin-Hôtel Dieu-Broca, Assistance publique-Hôpitaux de Paris, Paris, France.
authors.forename: G
authors.initials: G
authors.lastname: Collobert
authors.affiliation: Institut Cochin, université Sorbonne Paris Descartes, Paris, France; Inserm, U1016, Paris, France; CNRS (UMR 8104), Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Fouet
authors.affiliation: Laboratoire de bactériologie-virologie-hygiène, centre hospitalier universitaire de Limoges, 87042 Limoges cedex, France.
authors.forename: M-C
authors.initials: MC
authors.lastname: Ploy
authors.affiliation: Service de bactériologie, centre national de référence des streptocoques, groupe hospitalier universitaire Paris, centre Cochin-Hôtel Dieu-Broca, Assistance publique-Hôpitaux de Paris, Paris, France; Institut Cochin, université Sorbonne Paris Descartes, Paris, France; Inserm, U1016, Paris, France; CNRS (UMR 8104), Paris, France. Electronic address: claire.poyart@cch.aphp.fr.
authors.forename: C
authors.initials: C
authors.lastname: Poyart
mesh_terms: D000328:Adult; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002675:Child, Preschool; D002981:Clindamycin / Q000494:pharmacology* / Q000627:therapeutic use; D024881:Drug Resistance, Bacterial; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D013290:Streptococcal Infections / Q000188:drug therapy / Q000382:microbiology; D013297:Streptococcus pyogenes / Q000187:drug effects* / Q000235:genetics / Q000472:pathogenicity*; D014774:Virulence
chemical_list: D000900:Anti-Bacterial Agents; D002981:Clindamycin
keywords: Clindamycin resistance; Fasciite nécrosante; Infection invasive; Invasive infection; Necrotizing fasciitis; Résistance à la clindamycine; Streptococcus pyogenes; Virulence