RESUMO
BACKGROUND: In Bogotá, the Heptavalent Conjugate Vaccine (PCV7) was introduced into childhood immunization schedule since 2009. The aim of this study was to assess the changes in serotype distribution and penicillin susceptibility of Streptococcus pneumoniae isolates recovered from nasopharyngeal samples and invasive disease among children living in Bogotá, before and after PCV7 introduction. METHODS: Nasopharyngeal swabs were collected from healthy children aged between 12 and 18 months of age before (years 2005-2006) and after (2011) PCV7 introduction. Identification of S. pneumoniae was performed by multiplex PCR. Serotype was determined by PCR and Quellung reaction. Susceptibility to penicillin, ceftriaxone, trimethoprim-sulfamethoxazole, chloramphenicol, tetracycline and erythromycin was evaluated. In addition, distribution of serotypes and antimicrobial susceptibility before and after vaccine introduction among invasive isolates recovered from children ≤2 years old living in Bogotá was analyzed. RESULTS: Prevalence of pneumococcal nasopharyngeal carriage declined from 55.7% (137/246) in unvaccinated to 44.2% (87/197) (p=0.01) in vaccinated children. The proportion of children carrying PCV7 serotypes decreased from 23.6% (58/246) to 7.6% (15/197) (p<0.001). The decrease was counterbalanced by an increase in the proportion of non-PCV7 serotypes. The most prevalent among emerging serotypes were 15A, 15B, 15C, 11A and 35B. Among IPD isolates, PCV7 serotypes decreased from 69.1% (235/340) in 2005/2009 to 38.0% (32/84) in 2010/2011 (p<0.001). The increase of non-PCV7 serotypes was significant. Resistance to penicillin among invasive isolates recovered from meningitis decreased from 41.1% (30/73) in the pre-vaccine period to 14.2% (2/14) in post-vaccine period (p=0.02). CONCLUSIONS: A decrease in the prevalence of pneumococcal nasopharyngeal carriage following the introduction of PCV7 vaccine, have been overshadowed by an important surge in the prevalence of non-PCV7 serotypes. Systematic surveillance combining nasopharyngeal carriage surveys and IPD detection could help in evaluating the impact of conjugate vaccines.
Assuntos
Nasofaringe/microbiologia , Vacinas Pneumocócicas/uso terapêutico , Streptococcus pneumoniae/isolamento & purificação , Antibacterianos/farmacologia , Portador Sadio/imunologia , Colômbia , Estudos Transversais , Feminino , Vacina Pneumocócica Conjugada Heptavalente , Humanos , Lactente , Masculino , Testes de Sensibilidade Microbiana , Nasofaringe/efeitos dos fármacos , Infecções Pneumocócicas/prevenção & controle , Streptococcus pneumoniae/classificação , Streptococcus pneumoniae/efeitos dos fármacos , Streptococcus pneumoniae/genética , Streptococcus pneumoniae/imunologiaRESUMO
La vigilancia de la enfermedad invasora por Streptococcus pneumoniae permite detectar los cambios geográficos y cronológicos en los serotipos circulantes y en la sensibilidad antimicrobiana, monitorizando además el impacto de las vacunas sobre la enfermedad. Objetivos: Describir los serotipos aislados y la sensibilidad antimicrobiana en los pacientes pediatrics hospitalizados con enfermedad invasora por Streptococcus pneumoniae. Describir la enfermedad invasora por Streptococcus pneumoniae y sus complicaciones clínicas asociadas. Metodología: Estudio retrospectivo, longitudinal, incluye pacientes pediátricos hospitalizados en el Hospital Materno Infantil José Domingo de Obaldía en el periodo de enero de 2010 a junio de 2011; los cuales se cursaron con enfermedad invasora por Streptococcus pneumoniae como etiología en este periodo. El diagnóstico microbiológico se realizó por coaglutinación en líquidos corporales y cultivo del microorganismo. La cepa se aisló en el laboratorio de microbiología y se tipificó en el Laboratorio Central. La enfermedad invasora fue definida por el cuadro clínico y el aislamiento de Streptococcus pneumoniae de un sitio previamente estéril. Variables analizadas: edad, sexo, procedencia, sitio de infección, complicaciones, tiempo hospitalario, mortalidad, ingreso a UCI, anemia, VIH , letalidad. Resultados: Se revisaron 25 expedientes de pacientes con enfermedad invasora y aislamiento de Streptococcus pneumoniae. Dos fueron excluidos. 20 pacientes fueron menores de 5 años y 3 mayores de 5 años. 11 varones y 12 niñas. El 91% fueron indigenas. El 60.8% procedía de la Comarca Ngöbe Buglé. Promedio hospitalario 25.3 días, rango 1-93 días. 60.8% ingresó con enfermedad grave a la UCIP; 92.8% ameritó ventilación mecánica y 78.5% presentó choque. 34%(8) cursó con compromiso de SNC y el 30% (7) bacteriemia. Se tipificaron 14 cepas , el (78.5%) fue serotipo 5. Todos los aislados fueron sensibles a penicilina. 31% (5) resistentes a TMP/SMX. El 74% de los casos tenia hemoglobina menor de 10 g y solamente 3 habían completado su vacunación con PCV-7. Todo fueron VIH negativo. 30% de los pacientes fallecieron. Conclusiones: En los caso evaluados encontramos un predominio del Streptococcus pneumoniae tipo 5 en el 78.5% de los casos. Los serotipos 24F, 18C y 4 fueron aislados en 1 caso cada uno; el 100% fue sensible a penicilina. La población más afectada fue la raza indígena y los menores de 5 años. El SNC y respiratorio fueron los sitios primarios de infección. El 61% ingreso con enfermedad grave y el 30% falleció.
The monitoring of the invading disease by S. pneumoniae allows detecting geographic and temporary changes in antimicrobial sensitivity, besides monitoring the impact of the vaccines on the disease. Objectives: To describe to the isolate serotypes and antimicrobial sensitivy of Streptococcus pneumoniae to associate invasive disease in the pediatric patients hospitalized. Besides clinical manifestations and complications. Methods: Retrospective, longitudinal study. Pediatrics patients hospitalized in the Maternal Hospital in January 2010 to June 2011; in which Streptococcus pneumoniae was isolated as etiology of invasive disease. The microbiological diagnosis for Streptococcus pneumoniae was realized with coaglutination and culture of body fluids. The strain was isolated in the microbiology laboratory and it was typified in the Central Laboratory in Panama City. An invasive disease was defined by clinical manifestations and the isolation of Streptococcus pneumoniae of a previously sterile site. Analyzes variables: age, sex, origins, site of infection, complications, hospital time, death, admission to UCI, anemia , HIV, lethality. Results: 25 files with Streptococcus pneumoniae isolation and invasive disease were reviewed. Two were excluded. 20 patients were younger than 5 years and 3 oldest of 5 years. 11 were boys and 12 girls. 91% were indigenous. 60.8% came from Comarca Ngöbe Bugle. Hospital average 25, 3 days with range 1-93 days. 60.8% had serious disease and went to the UCIP; 92.8% need mechanical ventilation and 78.5% suffering shock. 34% (8) presented with commitment respiratory and SNC simultaneously. 70% (20) patients with pneumonia presented pleural effusion. 21,7% pericardial effusion and 30% (7) bacteremia. 14 isolate were typified, serotype 5 (78.5%). All were sensible to penicillin; TMP/SMX resistant 31% (5). 74% had hemoglobin less than 10 g and only 3 had completed their vaccination with PCV-7. All were HIV negative. 30% lethality. Conclusions: Streptococcus pneumoniae serotype 5 were strains predominance in the 78.5%. Others as 24 F, 18C and 4, 1 case of each serotypes; 100% were sensible to penicillin. The people more affected was indigenous race and the younger than 5 years. The respiratory and SNC were the primary infections sites. 61% come with serious illness and 30% died.