title: Streptococcus pneumoniae as cause of infection in infants less than 60 days of age: serotypes and antimicrobial susceptibility.
abstract: OBJECTIVE
  The aim of this study was to determine the distribution of serotypes and the antimicrobial susceptibilities of Streptococcus pneumoniae clinical isolates causing invasive and non-invasive disease in children aged ≤60 days in hospitals in Mexico.
  
  
  METHODS
  A 15-year retrospective study was conducted for the period 2000 to 2014. Pneumococcal clinical isolates were serotyped by Quellung reaction, and antimicrobial susceptibility testing was performed with the broth microdilution method.
  
  
  RESULTS
  A total of 126 pneumococcal isolates were collected. Pneumonia was the most frequent diagnosis (40.5%), followed by meningitis (29.4%), septicemia (16.7%), and other clinical entities, including otitis media and conjunctivitis (13.5%). The most frequent serotypes before the introduction of heptavalent pneumococcal conjugate vaccine (PCV7) were 19F, 23F, 7F, and 35B. Serotypes 3, 6A, 10A, 12F, and 15A/B increased after the introduction of PCV7. Serotype 19A was isolated most frequently in the pneumonia and meningitis cases only after the introduction of PCV7, and it displayed a high resistance to penicillin.
  
  
  CONCLUSIONS
  Although the number of infections in infants aged ≤60 days was low, such infections were not unusual events. New vaccination strategies should be evaluated to limit the risks in this age group.
authors.affiliation: Instituto Nacional de Salud Pública, Avenida Universidad 655, Cuernavaca, Morelos 62100, Mexico.
authors.forename: Araceli
authors.initials: A
authors.lastname: Soto-Noguerón
authors.affiliation: Instituto Nacional de Salud Pública, Avenida Universidad 655, Cuernavaca, Morelos 62100, Mexico.
authors.forename: María Noemí
authors.initials: MN
authors.lastname: Carnalla-Barajas
authors.affiliation: Unidad Médica de Alta Especialidad, Hospital de Pediatría Centro Médico Nacional SXXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico.
authors.forename: Fortino
authors.initials: F
authors.lastname: Solórzano-Santos
authors.affiliation: Instituto Nacional de Pediatría, Insurgentes Cuicuilco, Mexico City, Mexico.
authors.forename: José Luis
authors.initials: JL
authors.lastname: Arrendondo-García
authors.affiliation: Instituto Nacional de Pediatría, Insurgentes Cuicuilco, Mexico City, Mexico.
authors.forename: Patricia
authors.initials: P
authors.lastname: Arzate-Barbosa
authors.affiliation: Hospital General de Durango, Durango, Mexico.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Tinoco-Favila
authors.affiliation: Hospital General de León, Obregon, León, Guanajuato, Mexico.
authors.forename: Azarell
authors.initials: A
authors.lastname: Anzurez-Gutiérrez
authors.affiliation: Instituto Nacional de Salud Pública, Avenida Universidad 655, Cuernavaca, Morelos 62100, Mexico. Electronic address: igechaniz@insp.mx.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Echániz-Aviles
mesh_terms: D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008826:Microbial Sensitivity Tests; D011008:Pneumococcal Infections / Q000382:microbiology*; D012189:Retrospective Studies; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000187:drug effects
keywords: Antimicrobial susceptibility; Invasive pneumococcal diseases; Newborns; Pneumococcal vaccines; Serotypes; Streptococcus pneumoniae