J Med Microbiol. 2016 Sep 2. doi: 10.1099/jmm.0.000346. [Epub ahead of print]
In 2010, the 10-valent pneumococcal conjugate vaccine (PCV10) was introduced to the Brazilian childhood vaccination program. Concerns have been raised that non-vaccine serotypes could increase in prevalence and reduce the benefits of vaccination; therefore, we examined the non-PCV10 isolates recovered from meningitis during pre (January, 2008-May, 2010) and post-vaccine (June, 2010-December, 2012) periods. Surveillance for pneumococcal meningitis was established at the Reference Hospital of Infectious Diseases in Salvador, Brazil. Serotypes were determined by multiplex PCR and/or Quellung reaction. Antimicrobial susceptibility testing was conducted by E-test and broth microdilution. Genotyping employed pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). A total of 148 cases of meningitis were identified from January 2008 to December 2012, 77 (52%) of which were due to non-PCV10 isolates, with 50 (52.1%) from pre-vaccine and 27 (52%) post-vaccine periods. In the post-vaccine period, the non-PCV10 serotypes 12F (n = 6; 22.2%), 10A (n = 3; 11.1%), 15B (n = 2; 7.4%), and 18B (n = 2; 7.4%) were the most prevalent. Forty-three isolates (55.8%) were non-susceptible to one or more antibiotics. Non-susceptibility to penicillin was observed among serotypes 19A (3 isolates), 9N (1 isolate), and 12F (1 isolate). PFGE and MLST results demonstrated a wide genetic diversity among the isolates. During the early period following PCV10 introduction, no obvious emergence of a particular serotype was evident among non-PCV10 strains. This study underscores the importance of monitoring any changes among non-PCV10 cases after the introduction of PCV10.
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