Streptococcus pyogenes emm-types in northern Spain; population dynamics over a 7-year period

J Infect. 2014 Jan;68(1):50-7. doi: 10.1016/j.jinf.2013.08.013. Epub 2013 Aug 30.


Objective: To know the clinical entities caused by Streptococcus pyogenes as well as the characteristics of the isolates involved in them throughout a 7-year-study.

Methods: All S. pyogenes infectious episodes from the community recorded in the reference hospital of Gipuzkoa between 2005 and 2011 were included (n = 11,342). A random selection of 10% of total isolates was characterized by emm-type, T-type and multilocus-sequence-type.

Results: Main clinical presentations were: pharyngitis (n = 9467), otitis (n = 797), dermal infections (n = 506), and genital infections (n = 374). Highest frequency of pharyngitis and otitis was detected in children aged 2-8 years old and 1-year old, respectively. Among 29 emm-types, 8 (emm4, emm89, emm3, emm87, emm1, emm12, emm6 and emm75) grouped >70% of isolates. emm4 was significantly associated with 0-4 year-old patients, and emm89 and emm77 with patients >64 years; by infection type, emm4, emm87 and emm12 were associated with pharyngitis, emm1 and emm6 with otitis, emm89 with dermal infections, and emm77 with genital infections.

Conclusions: Predominant emm-type changed every year, although the diversity was similar throughout the study period. S. pyogenes pharyngitis maximum incidence presented at earlier age than expected. emm-type associations with age and specific clinical presentations were influenced by population immunity and strain tropism.

Keywords: Group A streptococcus infection; MLST; Otitis; Pharyngitis; T-type; Vaccine; emm-Subtype; emm-Type.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Antigens, Bacterial / genetics
  • Bacterial Outer Membrane Proteins / genetics
  • Carrier Proteins / genetics
  • Child
  • Child, Preschool
  • Ear Diseases / epidemiology
  • Ear Diseases / microbiology
  • Female
  • Humans
  • Infant
  • Male
  • Middle Aged
  • Pharyngitis / epidemiology
  • Pharyngitis / microbiology
  • Prevalence
  • Prospective Studies
  • Spain / epidemiology
  • Streptococcal Infections / epidemiology*
  • Streptococcal Infections / microbiology*
  • Streptococcal Vaccines
  • Streptococcus pyogenes / classification
  • Streptococcus pyogenes / genetics*
  • Young Adult


  • Antigens, Bacterial
  • Bacterial Outer Membrane Proteins
  • Carrier Proteins
  • Streptococcal Vaccines
  • streptococcal M protein