title: Impact of amoxicillin, associated or not with clavulanic acid, on pharyngeal colonization and selection of Streptococcus pneumoniae resistance in children under 5 years of age.
abstract: Among young children, pneumococcal nasopharyngeal colonization (NPC) rates of >90% have been described. The aim of our study was to assess the effect of amoxicillin exposure on the NPC. From Dec 2001 to Feb 2004, less than 5 years old children with respiratory symptoms and fever who were prescribed amoxicillin were eligible. Three nasopharyngeal swabs were taken: at the time of the initial visit (IV), 60 hours after amoxicillin discontinuation (end of treatment visit, ETV), and 4 weeks later (follow-up visit, FUV). One hundred and thirty four children were included. NPC was detected in 58.5%, 42.9% and 51% of <1, 1-2 and >2 years-old children respectively (NS). Vaccine serotypes (VS) or vaccine-related serotypes (VRS) were identified in 80%, 40% and 55% of <1-year-old, 1-2 year-old and >2-year-old children respectively (NS). The proportion of PNSSP was 60% in <1-year-old children, 43% in 1-2 year-old children and 40% in >2-year-old children (NS). 49 out of 134 (36.5%) children completed the three study visits. 51%, 22.4% and 46.9% of those were colonized at IV, ETV and FUV, respectively (p=0.007). The percentage of resistant SP was 28%, 45.5% and 8.7% (p=0.05) for penicillin. In children <1 year of age, a higher proportion of SP colonization, presence of VS and PNSSP was found. A downfall of NPC at the end of therapy was observed. NPC returned to baseline levels thanks to "de novo" colonization in half of the cases, a few weeks after.
authors.affiliation: Department of Paediatrics, Hospital Mutua de Terrassa, University of Barcelona, Terrassa, Barcelona, Spain.
authors.forename: Alvaro Díaz
authors.initials: AD
authors.lastname: Conradi
authors.forename: Esther
authors.initials: E
authors.lastname: Calbo
authors.forename: Eva
authors.initials: E
authors.lastname: Cuchí
authors.forename: Roger Garcia
authors.initials: RG
authors.lastname: Puig
authors.forename: César
authors.initials: C
authors.lastname: García-Rey
authors.forename: Luis Tobeña
authors.initials: LT
authors.lastname: Boada
authors.forename: Marisol
authors.initials: M
authors.lastname: Díaz-Infantes
authors.forename: José Emilio
authors.initials: JE
authors.lastname: Martín-Herrero
authors.forename: Javier
authors.initials: J
authors.lastname: Garau
mesh_terms: D000658:Amoxicillin / Q000494:pharmacology / Q000627:therapeutic use*; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D016009:Chi-Square Distribution; D002675:Child, Preschool; D019818:Clavulanic Acid / Q000494:pharmacology / Q000627:therapeutic use; D004352:Drug Resistance, Microbial; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009305:Nasopharynx / Q000382:microbiology*; D010403:Penicillin Resistance; D011008:Pneumococcal Infections / Q000188:drug therapy*; D015995:Prevalence; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D019818:Clavulanic Acid; D000658:Amoxicillin