[Epidemiology of acute otitis media caused by Streptococcus pneumoniae: emergence of serotype 19A].

In this study, the authors report the distribution of serogroups/serotypes and their susceptibility profiles of Streptococcus pneumoniae causing recurrent and difficulties to treat acute otitis media (AOM) in children obtained at the ENT outpatient clinic of Robert Debré Hospital in Paris, between 2002-2008 after the implementation of the 7-valent pneumococcal conjugate vaccine. In this retrospective study, 126 S. pneumoniae isolates were obtained by tympanocentesis from 126 children with AOM during three different periods: 2002-2003 (period 1), 2004-2005 (period 2), and 2006-2008 (period 3). In period 1, the most common serotype was 19F. Between period 1 and period 3, the proportion of serotype 19F decreased from 39 to 13% (P=0.03). In contrast, the proportion of serotype 19A increased from 25 to 60% (P=0.03). So, they observed that vaccine-related serotype 19A became dominant among young children with AOM in 2006-2008. Overall, 15.1% of the isolates were penicillin susceptible, 73.8% intermediate and 11.1% were resistant. Most (94%) of the S. pneumoniae serotype 19A were penicillin intermediate.