title: Antimicrobial resistance in relation to sero- and genotypes among invasive Streptococcus pneumoniae in Finland, 2007-2011.
abstract: OBJECTIVE
  We studied the serotypes and antimicrobial resistance of the invasive Streptococcus pneumoniae that had been isolated in Finland during 5 years. The 10-valent vaccine was introduced into the National Vaccination Programme in September 2010.
  
  
  METHODS
  We examined the antimicrobial resistance and serotype distribution of the invasive pneumococci (n=4,194) that had been isolated in Finland during 2007-2011. The penicillin-resistant (PEN R) (≥4 mg/L) isolates (n=12) were genotyped by MLST.
  
  
  RESULTS
  Serotype 14 was consistently the most prominent serotype, covering 18.0-20.1% of all the isolates. The proportion of serotypes 3, 19A, and 22F increased significantly, while that of 6B and the PCV10 vaccine serotypes combined decreased. PEN nonsusceptibility (≥0.12 mg/L) increased, ranging from 14.4% to 23.2% by year, and was the highest (28.5%) among the 0-2 year olds. The PEN and/or erythromycin (ERY) nonsusceptibility of several vaccine serotypes (4, 6B, 14, and 19F) increased significantly over the study period. The ERY nonsusceptibility was 26.6%. There was limited diversity among the PEN R isolates; all were a part of serotype 19F, 19A, or 14, and two globally disseminated genetic lineages carrying one or both pilus-encoding islets.
  
  
  CONCLUSIONS
  High and/or increasing nonsusceptibility rates underline the importance of monitoring the serotype distribution and antimicrobial susceptibility of pneumococci, especially after large-scale vaccination.
authors.affiliation: 1 Department of Infectious Disease Surveillance and Control, National Institute for Health and Welfare , Helsinki, Finland .
authors.forename: Lotta
authors.initials: L
authors.lastname: Siira
authors.forename: Jari
authors.initials: J
authors.lastname: Jalava
authors.forename: Tarja
authors.initials: T
authors.lastname: Kaijalainen
authors.forename: Jukka
authors.initials: J
authors.lastname: Ollgren
authors.forename: Outi
authors.initials: O
authors.lastname: Lyytikäinen
authors.forename: Anni
authors.initials: A
authors.lastname: Virolainen
mesh_terms: D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004917:Erythromycin / Q000627:therapeutic use; D010861:Fimbriae, Bacterial / Q000235:genetics*; D005387:Finland / Q000453:epidemiology; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D010406:Penicillins / Q000627:therapeutic use; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000276:immunology; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D014611:Vaccination
chemical_list: D000900:Anti-Bacterial Agents; D010406:Penicillins; D022242:Pneumococcal Vaccines; D004917:Erythromycin