title: Antimicrobial use and serotype distribution of nasopharyngeal Streptococcus pneumoniae isolates 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.
authors.affiliation: Department of Pediatrics, Division of Infectious Disease, University of Patras, School of Medicine, General University Hospital, Patras, Greece. syrogian@med.upatras.gr
authors.forename: George A
authors.initials: GA
authors.lastname: Syrogiannopoulos
authors.forename: George D
authors.initials: GD
authors.lastname: Katopodis
authors.forename: Ioanna N
authors.initials: IN
authors.lastname: Grivea
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Beratis
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D002353:Carrier State; D024881:Drug Resistance, Bacterial / Q000502:physiology*; D005260:Female; D006115:Greece; D006801:Humans; D007223:Infant; D008297:Male; D009305:Nasopharynx / Q000382:microbiology*; D012703:Serotyping; D013290:Streptococcal Infections / Q000382:microbiology*; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents