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Aim: This study aims to describe the microbiology of middle ear fluid (MEF) in a cohort of children vaccinated with Streptococcus pneumoniae conjugate vaccine (PCV7) having ventilation tube insertion. Nasopharyngeal (NP) carriage of otopathogens in these children is compared with children without history of otitis media.Methods: Between May and November 2011, MEF and NP samples from 325 children aged <3 years were collected in three major centres in New Zealand at the time of ventilation tube insertion. An age-matched non-otitis-prone comparison group of 137 children had NP samples taken. A questionnaire was completed by both groups.Results: Immunisation coverage with at least one dose of PCV7 was 97%. Haemophilus influenzae was cultured in 19.4% of MEF and was polymerase chain reaction (PCR) positive in 43.4%. S. pneumoniae and Moraxella catarrhalis were cultured in <10% of MEF samples but were PCR positive for 23.1% and 38.7%, respectively. H. influenzae was the most common organism isolated from NP samples (60%) in the grommet group, while M. catarrhalis (56%) was the most common in the non-otitis prone group. S. pneumoniae was more commonly found in the nasopharynx of children with ear disease (41% vs. 29%). 19F was the most prominent S. pneumoniae serotype in NP samples of both groups, but no serotype dominated in MEF. Ninety-five per cent of H. influenzae isolates were confirmed to be non-typeable H. influenzae.Conclusion: In this cohort of children with established ear disease requiring surgical intervention, non-typeable H. influenzae is the dominant pathogen in both the nasopharynx and MEF. [ABSTRACT FROM AUTHOR]

Otitis media (OM) is a major reason for antibiotic consumption and surgery in children. Nasopharyngeal carriage of otopathogens, Streptococcus pneumoniae and nontypeable Haemophilus influenzae (NTHi), is a prerequisite for development of OM, and increased nasopharyngeal otopathogen density correlates with disease onset. Vaccines can reduce or eliminate otopathogen carriage, as demonstrated for pneumococcal serotypes included in pneumococcal conjugate vaccines (PCV). The 10-valent PCV (PCV10) includes an NTHi carrier protein, and in 2011 superseded 7-valent PCV on the New Zealand Immunisation Program. Data are conflicting on whether PCV10 provides protection against NTHi carriage or disease. Assessing this in otitis-prone cohorts is important for OM prevention. We compared otopathogen density in the nasopharynx and middle ear of New Zealand PCV7-vaccinated and PCV10-vaccinated otitis-prone and non-otitis-prone children to determine PCV10 impact on NTHi and S. pneumoniae carriage. We applied qPCR to specimens collected from 217 PCV7-vaccinated children (147 otitis-prone and 70 non-otitis-prone) and 240 PCV10-vaccinated children (178 otitis-prone and 62 non-otitis-prone). After correcting for age and day-care attendance, no difference was observed between NTHi density in the nasopharynx of PCV7-vaccinated versus PCV10-vaccinated otitis-prone (p = 0.563) or non-otitis-prone (p = 0.513) children. In contrast, pneumococcal nasopharyngeal density was higher in PCV10-vaccinated otitis-prone children than PCV7-vaccinated otitis-prone children (p = 0.003). There was no difference in otopathogen density in middle ear effusion from PCV7-vaccinated versus PCV10-vaccinated otitis-prone children (NTHi p = 0.918; S. pneumoniae p = 0.415). When pneumococcal carriage was assessed by vaccine serotypes (VT) and non-vaccine serotypes (NVT), there was no difference in VT density (p = 0.546) or NVT density (p = 0.315) between all PCV7-vaccinated versus all PCV10-vaccinated children. In summary, PCV10 did not reduce NTHi density in the nasopharynx or middle ear, and was associated with increased pneumococcal nasopharyngeal density in otitis-prone children in New Zealand. Development of therapies that prevent or reduce otopathogen colonisation density in the nasopharynx are warranted to reduce the burden of OM. [ABSTRACT FROM AUTHOR]