title: Comparison of Serotype Prevalence of Pneumococci Isolated from Middle Ear, Lower Respiratory Tract and Invasive Disease Prior to Vaccination in Iceland.
abstract: BACKGROUND
  Information on pneumococcal serotype distribution before vaccination is a prerequisite for evaluation of vaccine effect. The aim was to investigate the prevalence of pneumococcal serotypes isolated from middle ear (ME), lower respiratory tract (LRT) and from invasive disease (IPD) in Iceland prior to implementation of ten-valent pneumococcal Haemophilus influenzae protein D conjugate vaccine (PHiD-CV-10) into the infant vaccination program (April 2011).
  
  
  RESULTS
  All isolates cultured 2007-2011 from ME, LRT and IPD identified as pneumococci were serotyped and tested for susceptibility at the Clinical Microbiology Department, Landspitali University Hospital that serves approximately 85% of the Icelandic population. Pneumococcal isolates were 1711 and 1616 (94.4%) were available for serotyping and included. Isolates belonging to PHiD-CV10 serotypes (VTs) were 1052 (65.1%). Isolates from ME were 879 (54.4%), with 639 (72.7%) from 0-1 year old patients and 651 of VTs (74%). Isolates from LRT were 564 (34.9%), with 292 (51.8%) from ≥65 years old patients, and 300 (53.2%) of VTs. IPD isolates were 173 (10.7%), although more evenly distributed according to age than isolates from the other sites most were from adults and the youngest age group,101 (58.4%) isolates were of VTs. The most common serotype was 19F, 583 (36.1%). Its prevalence was highest in ME, 400 (45.5%), 172 (30.5%) in LRT and 11 isolates (6.4%), in IPD. Penicillin non-susceptible isolates were 651 (40.3%), mainly belonging to VTs, 611 (93.9%), including 535 (82.2%) of 19F.
  
  
  CONCLUSIONS
  Multiresistant isolates of serotype 19F were highly prevalent, especially from ME of young children but also from LRT of adults. Serotype 14 was the most common serotype in IPD. The rate of VTs was high and almost all PNSP were of VTs. There was great difference in vaccine coverage between sampling sites, also reflecting difference in vaccine coverage by age groups.
authors.affiliation: Department of Clinical Microbiology, Landspitali University Hospital, Reykjavik, Iceland.|Faculty of Medicine, University of Iceland, Reykjavik, Iceland.|BioMedical Center of the University of Iceland, Reykjavik, Iceland.
authors.forename: Martha Á
authors.identifier: http://orcid.org/0000-0002-9764-9943
authors.initials: MÁ
authors.lastname: Hjálmarsdóttir
authors.affiliation: Department of Clinical Microbiology, Landspitali University Hospital, Reykjavik, Iceland.|Faculty of Medicine, University of Iceland, Reykjavik, Iceland.|BioMedical Center of the University of Iceland, Reykjavik, Iceland.
authors.forename: Sigríður Júlía
authors.initials: SJ
authors.lastname: Quirk
authors.affiliation: Department of Clinical Microbiology, Landspitali University Hospital, Reykjavik, Iceland.|Faculty of Medicine, University of Iceland, Reykjavik, Iceland.|BioMedical Center of the University of Iceland, Reykjavik, Iceland.
authors.forename: Gunnsteinn
authors.initials: G
authors.lastname: Haraldsson
authors.affiliation: Department of Clinical Microbiology, Landspitali University Hospital, Reykjavik, Iceland.|Faculty of Medicine, University of Iceland, Reykjavik, Iceland.|BioMedical Center of the University of Iceland, Reykjavik, Iceland.
authors.forename: Helga
authors.initials: H
authors.lastname: Erlendsdóttir
authors.affiliation: Faculty of Medicine, University of Iceland, Reykjavik, Iceland.|Children's Hospital, Landspitali University Hospital, Reykjavik, Iceland.
authors.forename: Ásgeir
authors.initials: Á
authors.lastname: Haraldsson
authors.affiliation: Department of Clinical Microbiology, Landspitali University Hospital, Reykjavik, Iceland.|Faculty of Medicine, University of Iceland, Reykjavik, Iceland.|BioMedical Center of the University of Iceland, Reykjavik, Iceland.
authors.forename: Karl G
authors.initials: KG
authors.lastname: Kristinsson
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D004432:Ear, Middle / Q000187:drug effects / Q000276:immunology / Q000382:microbiology*; D005260:Female; D006193:Haemophilus influenzae / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D010403:Penicillin Resistance / Q000235:genetics; D010406:Penicillins / Q000494:pharmacology; D011008:Pneumococcal Infections / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage* / Q000096:biosynthesis / Q000235:genetics; D015995:Prevalence; D012137:Respiratory System / Q000187:drug effects / Q000276:immunology / Q000382:microbiology*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification / Q000187:drug effects / Q000276:immunology* / Q000302:isolation & purification; D014611:Vaccination / Q000706:statistics & numerical data*; D018074:Vaccines, Conjugate
chemical_list: D000900:Anti-Bacterial Agents; D010406:Penicillins; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate