Streptococcus pneumoniae serotype 6C in Costa Rican children with otitis media before introduction of the 7-valent pneumococcal conjugated vaccine into the national immunization program
Artículo académico
During the years 1999 through 2008 middle ear fluid (MEF) and nasopharyngeal/oropharyngeal (NP/OP) samples were obtained from Costa Rican children with otitis media (OM). Streptococcus pneumoniae was identified and serotyped according to standard procedures. A total of 1,389 MEF isolates were collected, of which 353 (25%) were S. pneumoniae. Serotyping was performed in 286/353 (81%) isolates, of which 40 (14%) were serogroup 6: serotype 6A (10/40; 25%), 6B (27/40; 67%) and 6C (3/40; 8%). Among 755 NP/OP S. pneumoniae isolated, 537 (71%) were serotyped and serogroup 6 was identified in 112 (21%) isolates: 6A (24/112; 21%), 6B (78/112; 70%), and 6C (10/112; 9%). Twenty percent, 86% and 0% of serotypes 6A, 6B and 6C isolated from the MEF, respectively, were penicillin non-susceptible (MIC 0.06 µg/mL) and among the NP/OP isolates, 25%, 17.9% and 10%, respectively, were penicillin non-susceptible. Our results show that in Costa Rican children with OM, S. pneumoniae serotype 6C is an infrequent cause of OM and is sporadically found in NP/OP samples
