J Med Microbiol. 2016 Sep 2. doi: 10.1099/jmm.0.000346. [Epub ahead of print]

Genetic profiles and antimicrobial resistance of Streptococcus pneumoniae non-PCV10 serotype isolates recovered from meningitis cases in Salvador, Brazil.

Azevedo J1, Dos Anjos ES2, Cordeiro SM3, Dos Santos MS4, Escobar EC5, Lobo PR6, Carvalho MD7, Reis MG8, Reis JN9, Campos LC10.

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Abstract

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.

PMID: 27599851 DOI: 10.1099/jmm.0.000346

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