title: Pneumococcal Mastoiditis in Children Before and After the Introduction of Conjugate Pneumococcal Vaccines.
abstract: OBJECTIVE
  To determine whether serotype distribution and antibiotic resistance of Streptococcus pneumoniae acute mastoiditis (AM) in children have changed in the post pneumococcal conjugate vaccines (PCVs) era.
  
  
  METHODS
  Medical records of pneumococcal AM cases, in a tertiary pediatric hospital were reviewed from January 1999 to December 2014. S. pneumoniae isolates were serotyped using the quellung reaction and tested for antibiotic susceptibility by E-test and for macrolide resistance genes by polymerase chain reaction.
  
  
  RESULTS
  Among 334 children with AM, S. pneumoniae was isolated from 89 (26.6%) with median age 22 months (interquartile range: 12-30 months). S. pneumoniae was recovered from ear fluid (58%), mastoid specimens (35.2%) and blood (6.8%). Resistance to penicillin, erythromycin and clindamycin was 12.4%, 49.4% and 18%, respectively. Distribution of pneumococcal serotypes before (1999-2005), after the introduction of PCV7 (2006-2010) and after PCV13 (2011-2014) was found: for the PCV7 serotypes 81%, 25% and 0% (P < 0.0001), for PCV13 additional serotypes 16.3%, 70.8% and 63.6% (P < 0.0001) and for non-PCV serotypes 2.3%, 4.1% and 36.3% (P = 0.0002), respectively. Significant increase was detected for the serotype 19A after PCV7, and this trend was not changed after PCV13 (2.3%, 50% and 50%, respectively; P < 0.0001). A significant proportion of resistant isolates to penicillin (54.5%) and erythromycin (34.8%) was identified as 19A.
  
  
  CONCLUSIONS
  After the introduction of PCV7, a significant increase of serotype 19A and replacement of PCVs serotypes was identified. After PCV13, the overall proportion of pneumococcal mastoiditis and the incidence of serotype 19A were not significantly declined. A significant proportion of resistant isolates to penicillin and erythromycin is attributed to serotype 19A.
authors.affiliation: From the *First Department of Pediatrics, †Department of Otolaryngology Head and Neck Surgery, ‡Department of Clinical Microbiology, Aghia Sophia Children's Hospital, University of Athens, Athens, Greece; and §Department of Microbiology, Medical School, University of Athens, Athens, Greece.
authors.forename: Emmanouil I
authors.initials: EI
authors.lastname: Koutouzis
authors.forename: Athanasios
authors.initials: A
authors.lastname: Michos
authors.forename: Foteini I
authors.initials: FI
authors.lastname: Koutouzi
authors.forename: Panagiota
authors.initials: P
authors.lastname: Chatzichristou
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Parpounas
authors.forename: Angeliki
authors.initials: A
authors.lastname: Georgaki
authors.forename: Maria
authors.initials: M
authors.lastname: Theodoridou
authors.forename: Athanasios
authors.initials: A
authors.lastname: Tsakris
authors.forename: Vassiliki P
authors.initials: VP
authors.lastname: Syriopoulou
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002675:Child, Preschool; D024881:Drug Resistance, Bacterial; D005260:Female; D006115:Greece / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008297:Male; D008417:Mastoiditis / Q000453:epidemiology* / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology* / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000276:immunology; D065288:Serogroup; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000187:drug effects / Q000302:isolation & purification; D014611:Vaccination; D018074:Vaccines, Conjugate / Q000276:immunology
chemical_list: D000900:Anti-Bacterial Agents; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate