Development of pneumococcal mastoiditis due to multidrug-resistant serotype 19A despite three doses of 13-valent pneumococcal vaccine.

Acute mastoiditis is a potential complication of acute otitis media (AOM), with Streptococcus pneumoniae historically the most common pathogen isolated. Following the release of the 7-valent pneumococcal conjugate vaccine in 2000, a marked decline in invasive pneumococcal disease and a smaller reduction in pneumococcal AOM were observed, but data regarding its impact on acute mastoiditis are limited. With the recent introduction of the 13-valent pneumococcal conjugate vaccine (PCV13), it is anticipated that pneumococcal AOM and invasive disease will further diminish. We report a case of acute mastoiditis from a multidrug-resistant serotype 19A S. pneumoniae in an immunocompetent child who had received three PCV13 vaccinations.