Epidemiology of an upsurge of invasive group A streptococcal infections in Ireland, 2012-2015

J Infect. 2018 Sep;77(3):183-190. doi: 10.1016/j.jinf.2018.05.010. Epub 2018 Jun 20.

Abstract

Objectives: Group A streptococcus (GAS) is responsible for mild to very severe disease. The epidemiology of an upsurge in invasive GAS (iGAS) infections in Ireland, 2012-2015 was investigated.

Methods: Epidemiological typing of iGAS (n = 473) isolates was performed and compared to non-invasive (n = 517) isolates. Clinical data of notified iGAS was obtained from the national infectious disease information system.

Results: Annual incidences of iGAS cases (n = 561) were 2.33-3.66 per 100,000 population. Bacteraemia was the most common clinical presentation (75%) followed by focus without bacteraemia (19%) and necrotizing faciitis (7%). Streptococcal toxic shock syndrome occurred in 19% of presentations. The main invasive emm types in rank order were emm1, emm3, emm28, emm12 and emm89 whereas emm4, emm28, emm3, emm12, emm89 and emm1 predominated in non-invasive infections. Invasive emm1 and emm3 showed annual fluctuations (15-48% and 4-37%, respectively) and predominated in most clinical presentations of iGAS. Superantigens speA, speG, speJ was associated with iGAS disease and, speC, speI and ssa with non-invasive infections. There was 4.3% erythromycin and 5.6% tetracycline resistance. The main resistant types were emm11, emm28 and emm77.

Conclusions: Cyclic increases in emm1 and emm3 occurred during the iGAS upsurge. Continued surveillance of GAS is therefore essential given the epidemiological changes that occur in a short time period.

Keywords: Antimicrobial susceptibility; Epidemiology; Invasive; Pharyngitis; Streptococcus pyogenes; Superantigen.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Antigens, Bacterial / genetics
  • Bacteremia / epidemiology*
  • Bacteremia / microbiology
  • Bacterial Outer Membrane Proteins / genetics
  • Carrier Proteins / genetics
  • Child
  • Child, Preschool
  • Drug Resistance, Bacterial
  • Fasciitis, Necrotizing / epidemiology
  • Fasciitis, Necrotizing / microbiology
  • Genotype
  • Genotyping Techniques
  • Humans
  • Incidence
  • Infant
  • Infant, Newborn
  • Ireland / epidemiology
  • Middle Aged
  • Molecular Typing
  • Prospective Studies
  • Retrospective Studies
  • Shock, Septic / epidemiology
  • Shock, Septic / microbiology
  • Streptococcal Infections / epidemiology*
  • Streptococcal Infections / microbiology
  • Streptococcus pyogenes / classification
  • Streptococcus pyogenes / isolation & purification*
  • Young Adult

Substances

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