[Haemophilus influenzae nasopharyngeal colonization in children]. / Haemophilus influenzae, colonización nasofaríngea en niños menores de cinco años.

OBJECTIVE: to determine frequency, serotypes, biotypes and susceptibility to eight antibiotics in Haemophilus influenzae nasopharyngeal isolates in children under five years old from Mexico City. METHODS: cross-sectional survey including children two months to five years old. A nasopharyngeal sample was taken. Haemophilus influenzae identification, serotyping, biotyping and antimicrobial susceptibility were performed. RESULTS: a sample of 573 children were included. In 88/573 (15.3 %) H. influenzae was isolated, corresponding in 7/573 (1.2 %) to Hib, 3/573 (0.5 %) to Hi a, c, d, f and 78/573 (13.6 %) to Nontypable Hi. Among Hib carriers, 6 had received only one or two doses of specific vaccine. Biotype VIII (76.1 %) was the predominant. All isolates were susceptible to the antibiotics, but one Hib strain was resistant to erithromycin. CONCLUSIONS: nontypable Haemophilus influenzae was predominant. Colonization by Hib in children under 5 years old was low (1.2 %), occurring in children with an incomplete vaccination schedule.

[Prevalence of Streptococcus pneumoniae serotypes on nasopharyngeal colonization in children of Mexico City]. / Serotipos prevalentes de Streptococcus pneumoniae colonizadores de nasofaringe, en niños del Distrito Federal.

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. PATIENTS AND 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.

Serotipos prevalentes de Streptococcus pneumoniae colonizadores de nasofaringe, en niños del Distrito Federal / Prevalence of Streptococcus pneumoniae serotypes on nasopharyngeal colonization in children of Mexico City

OBJETIVO: Determinar frecuencia, serotipos y susceptibilidad a ocho antimicrobianos en Streptococcus pneumoniae aislados de la nasofaringe de una muestra representativa de niños menores de cinco años de edad residentes en el Distrito Federal. MATERIAL Y MÉTODOS: Estudio transversal, hecho de febrero de 2002 a enero de 2003. Se incluyeron niños de 2 meses a 5 años. A los seleccionados se les tomó una muestra de exudado faríngeo con hisopo de alginato de calcio. Bajo técnicas ya establecidas se realizó identificación, tipificación y susceptibilidad a ocho antimicrobianos de los aislamientos de S. pneumoniae. Se utilizó estadística descriptiva, prueba de Ji cuadrada y razón de momios (IC 95 por ciento) para los factores de riesgo. RESULTADOS: Se estudiaron 573 niños. En 122/573 (21.4 por ciento) niños se aisló S. pneumoniae. Los serotipos más frecuentes fueron el 23F, 35, 19F, 11A y 15A; 46 por ciento de los serotipos encontrados no son cubiertos con la vacuna heptavalente. Se encontró 12 por ciento de susceptibilidad reducida a la penicilina, con 3 por ciento de cepas con alta resistencia; la resistencia a eritromicina fue >30 por ciento y para trimetoprim-sulfametoxazol (TMP/SMX) >40 por ciento. No hubo cepas resistentes a vancomicina, cefotaxima, amoxicilina-clavulanato, cloranfenicol o ampicilina. CONCLUSIONES: El porcentaje de serotipos de S. pneumoniae en portadores nasofaríngeos no cubiertos por la vacuna heptavalente es alto, y la resistencia a macrólidos y TMP/SMX es elevada, lo que debe alertar al grupo médico.