Microbiology of Otitis Media in Costarrican Children After PCV13 Introduction
Condition: Otitis Media in Children
MeSH terms: Otitis; Otitis Media
Study type: Observational

Summary: 
      Studies which describe the bacterial aetiology and antimicrobial susceptibility in AOM
      children in Latin America are scarce. Interestingly, when the MEF microbiology was analyzed
      among 1,108 children aged 2-92 months with OM between years 2002 and 2007, non-typable H.
      influenzae was the most common pathogen isolated from the MEF of children with a otitis media
      failing to appropriate antimicrobial therapy.

      PCV-7 (3 + 1 regimen) was introduced into the Costa Rican national immunization program in
      January 2009 and in August/September of 2011, it was changed for PCV 13 (-2+1 regimen).
      Following PCV-7 universal introduction in Costa Rica, between March of 2010 and January of
      2011, MEF samples from Costa Rican children with OM, having received 0-4 PCV 7 vaccine doses,
      were obtained via tympanocentesis (88%) or from spontaneous otorrhoea (12%). It was
      interesting to observed that among the initial 134 OM episodes, the most common bacterial
      pathogen identified was H. influenzae (55%) followed by S. pneumoniae (31%) and that among
      the S. pneumoniae episodes, 55% were already non-PCV-7 serotypes and that 25% of these
      isolates were multi-drug resistant.

      The primary objectives of the study are to analyze the effect of early universal utilization
      of PCV-13 in Costa Rican children with the number of H. influenzae and PCV-13- S. pneumoniae
      positive MEF cultures by comparing the data collected prospectively and by the same group of
      investigators that have collected the original data since 1992, from children for the
      post-PCV-13 introduction with anonymised information collected retrospectively pre-PCV-7 data
      (1999-2004) during a transition period in which PCV-7 was used in only the private settings
      (2005-2008) and during universal use of PCV-7 (2009-September 2011).
    

Detailed description: 
      Studies which describe the bacterial aetiology and antimicrobial susceptibility in AOM
      children in Latin America are scarce, however, since 1991, investigators in Costa Rica have
      follow the MEF microbiology of Costa Rican children with AOM including data before PCV 7,
      during a period of time when PCV-7 was used among high risk children and after universal
      introduction of a 3 + 1 PCV-7 regimen in Costa Rica. Published data from Costa Rican children
      with OM, collected between 1992 and 2007, describing the MEF microbiology indicated that
      overall S. pneumoniae was the most frequent pathogen followed by non-typable H. influenzae,
      M. catarrhalis and S. pyogenes. Interestingly, when the MEF microbiology was analyzed among
      1,108 children aged 2-92 months with OM between years 2002 and 2007, non-typable H.
      influenzae was the mosto common pathogen isolated from the MEF of children with a otitis
      media failing to appropriate antimicrobial therapy.

      PCV-7 (3 + 1 regimen) was introduced into the Costa Rican national immunization program in
      January 2009 and in August/September of 2011, it was changed for PCV 13 (-2+1 regimen).
      Following PCV-7 universal introduction in Costa Rica, between March of 2010 and January of
      2011, MEF samples from Costa Rican children with OM, having received 0-4 PCV 7 vaccine doses,
      were obtained via tympanocentesis (88%) or from spontaneous otorrhoea (12%). It was
      interesting to observed that among the initial 134 OM episodes, the most common bacterial
      pathogen identified was H. influenzae (55%) followed by S. pneumoniae (31%) and that among
      the S. pneumoniae episodes, 55% were already non-PCV-7 serotypes and that 25% of these
      isolates were multi-drug resistant.

      Based on the available information describing the worldwide modifications in the MEF
      microbiology of PCV-7 vaccinated children with OM (a proportional increase of cases caused by
      H. influenzae and non-PCV-7 S. pneumoniae serotypes), the primary objectives of the study are
      to analyze the effect of early universal utilization of PCV-13 in Costa Rican children with
      the number of H. influenzae and PCV-13- S. pneumoniae positive MEF cultures by comparing the
      data collected prospectively and by the same group of investigators that have collected the
      original data since 1992, from children for the post-PCV-13 introduction with anonymised
      information collected retrospectively pre-PCV-7 data (1999-2004) during a transition period
      in which PCV-7 was used in only the private settings (2005-2008) and during universal use of
      PCV-7 (2009-September 2011).
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Children aged more than 3 months to less than 6 years, visiting with otitis media and from
        whom a middle ear fluid sample has been obtained.

        A cohort of children with the first episode of otitis media occurring before or at the age
        of 24 months of age and at least one month after completion of two doses of pneumococcal 13
        valent vaccine will be followed until the participant completes 36 months of life.
      
Biospecimen description: 
      Bacteria isolated from children with otitis media
    
Keywords: otitis media; microbiology; vaccines