Antimicrobial Use and Serotype Distribution of NasopharyngealStreptococcus pneumoniaeIsolates Recovered from Greek Children Younger than 2 Years Old

Abstract

The serotype distribution of 781 nasopharyngeal pneumococcal isolates recovered from 2448 unselected children aged 2-23 months was studied. Only 3.9% of the children for whom cultures were performed attended day care centers. The proportions of pneumococcal isolates that belonged to serotypes related to the 7-, 9- and 11-valent conjugate pneumococcal vaccine were 65%, 66%, and 70%, respectively. The pneumococcal carriage rate among untreated children was 34%; the rates among children treated with antibiotics during the periods 1-30 or 31-60 days before the time of nasopharyngeal sampling were 25% and 36%, respectively. There was a significant positive association between antimicrobial use and carriage of antibiotic-resistant pneumococci, which belonged mainly to vaccine-related serotypes. The proportion of isolates that belonged to vaccine-related serotypes in untreated carriers was 72%; however, the proportions in carriers treated 1-30 days or 31-60 days before sampling were 66% and 56%, respectively. In the nasopharynx, antimicrobial use selects for antibiotic-resistant pneumococci, mainly of vaccine-related serotypes, whereas it may promote an increase in the frequency of colonization with nonvaccine serotypes.

Dynamics of pneumococcal carriage among healthy Icelandic children attending day-care centres

“…All except serotype 19A are among the most common serotypes in carriage and invasive disease according to 3 other studies [28 Á/30]. 51% of the pneumococci belonged to serotypes covered by the new heptavalent protein conjugated pneumococcal vaccine (4, 6B, 9V, 14, 18C, 19F, 23F), which is comparable to other studies [28,29]. Due to cross reactivity, the vaccine may also be effective against 5 additional serotypes (6A, 9N, 18B, 19A, 23A), expanding its coverage to as much as 79% of S. pneumoniae isolates of this study, including almost all PNSP.…”

Antibiotic susceptibility of acute otitis media pathogens in otitis-prone Belgian children

“…In a 1996 to 1999 collection of paediatric AOM S. pneumoniae isolates, 7-valent pneumococcal conjugate vaccine-related serotypes were shown to account for 98.3% of all penicillin-non-susceptible and 99.0% of all cotrimoxazole-non-susceptible strains [11]. Similar findings were recently reported in Greek toddlers where 78% of the nasopharyngeal S. pneumoniae isolates resistant to one ore more antibiotic were covered by the 7-valent pneumococcal conjugate vaccine [20]. Since antimicrobial resistant and multi-drug resistant pneumococcal clones almost exclusively belong to serotypes included in the 7-valent pneumococcal conjugate vaccine and immunisation has been shown to reduce nasopharyngeal carriage of vaccine serotypes [15], widespread vaccination might prevent AOM caused by antibiotic resistant pneumococci in the near future.…”

“…Nasopharyngeal samples obtained at study entry in all children (n=74) and at fixed time points (4,7,14,20 and 26 months) during follow-up in the placebo-treated group (n=36) were evaluated for this study. No antibiotic therapy was administered at least 2 weeks prior to sampling.…”

Streptococcus pneumoniae aislados durante 2002-2006: serotipos y resistencia antibiótica. Correlación con las vacunas existentes

“…Considerando los serotipos más frecuentes de portadores o colonizados, se ha informado sobre 6 serotipos (2,8) y 5 serotipos (9) ; dos serotipos (6A y 15B) de portadores nuestros no estaban en esos grupos.…”

“…La nasofaringe es el principal reservorio de S. pneumoniae y el estado de portador precede en la mayoría de los casos a una infección neumocócica (2) . La vacuna polisacárida antineumocócica 23-valente, en uso desde 1982, no genera respuesta inmunológica en niños menores de 2 años.…”