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
Affiliations: Instituto de Atención Pediátrica, San
José, Costa Rica | Universidad de Ciencias Médicas San José,
Costa Rica | Pediatric Infectious Disease Unit, Soroka University
Medical Center and the Faculty of Health Sciences, Ben-Gurion University of the
Negev, Beer-Sheva, Israel
Note: [] Correspondence: Adriano Arguedas, MD, P.O. Box 607-1150 La Uruca, San José, Costa
Rica. Tel.: +506 222 2470; Fax: +506 221 3894; E-mail: aarguedas@iped.net
Abstract: 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.
