title: [Prevalence of Streptococcus pneumoniae serotypes on nasopharyngeal colonization in children of Mexico City].
abstract: OBJECTIVE
  To determine the frequency, serotypes and susceptibility profiles to eight antimicrobials in Streptococcus pneumoniae nasopharyngeal isolates from a representative sample of children under 5 years of age, residents of Mexico City.
  
  
  METHODS
  A cross-sectional survey was conducted in 573 children aged 2 months to 5 years.A nasopharyngeal sample was taken. S. pneumoniae identification, capsular serotyping and antimicrobial susceptibility to eight antimicrobials were performed according to standardized methods.
  
  
  RESULTS
  S. pneumoniae was isolated in 122/573 (21.4%) children. The most frequent capsular serotypes were 23F, 35, 19F, 11A and 15A; 46% of isolates corresponded to serotypes not included in the heptavalent vaccine. Low penicillin susceptibility was found in 12% of strains with 3% of highly resistant penicillin strains; erythromycin resistance was >30% and trimethoprim-sulfamethoxazole resistance >40%. None of the isolates was resistant to vancomycin, cefotaxime, amoxacillin-clavulanate, chloramphenicol or ampicillin.
  
  
  CONCLUSIONS
  Several S. pneumoniae serotypes from nasopharyngeal carriers are not included in the heptavalent vaccine. Resistance to trimethoprim-sulfamethoxazole and macrolides is high. The medical community should be aware of these results.
authors.affiliation: Departamento de Infectología, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, DF México. forsosa@starmedia.com
authors.forename: Fortino
authors.initials: F
authors.lastname: Solórzano-Santos
authors.forename: Laura Alicia
authors.initials: LA
authors.lastname: Ortiz-Ocampo
authors.forename: Ma Guadalupe
authors.initials: MG
authors.lastname: Miranda-Novales
authors.forename: Gabriela
authors.initials: G
authors.lastname: Echániz-Avilés
authors.forename: Araceli
authors.initials: A
authors.lastname: Soto-Noguerón
authors.forename: Héctor
authors.initials: H
authors.lastname: Guiscafré-Gallardo
mesh_terms: D000367:Age Factors; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D008297:Male; D008800:Mexico; D008826:Microbial Sensitivity Tests; D009305:Nasopharynx / Q000382:microbiology*; D015995:Prevalence; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents