[Prevalence of Streptococcus pneumoniae serotypes on nasopharyngeal colonization in children of Mexico City].
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.
Solórzano-Santos
Fortino
F
Departamento de Infectología, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, DF México. forsosa@starmedia.com
Ortiz-Ocampo
Laura Alicia
LA
Miranda-Novales
Ma Guadalupe
MG
Echániz-Avilés
Gabriela
G
Soto-Noguerón
Araceli
A
Guiscafré-Gallardo
Héctor
H
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
D000900:Anti-Bacterial Agents