ABSTRACT
La incorporación de la vacuna conjugada antineumocóc-cica 10 valente (PCV10) en lactantes en Chile el año 2011 ha permitido reducir las hospitalizaciones y muertes por neumonía en este grupo etario. Sin embargo, se ha observado desde entonces un aumento progresivo de los aislados de Streptococcus pneumoniae del serotipo 19A no incluido en la vacuna en uso (de < 5% del total de cepas recibidas en el Laboratorio de Referencia Nacional del Instituto de Salud Pública para vigilancia de infecciones invasores causadas por S. pneumoniae hasta el año 2010, a 12-23% en los años 2014-2015). En lactantes, el serotipo 19A representaba 4 a 8% de los aislados en la era pre vacuna, porcentaje que se incrementa a 25% el 2014. Este aumento ha ocurrido en dos terceras partes de las regiones administrativas del país. Cepas del serotipo 19A de pacientes menores de 5 años, muestran 25% de resistencia a penicilina para aislados extra-meníngeos y casi 100% para aislados de meningitis. El análisis genético de las cepas del serotipo 19A ha demostrado que 48% pertenecen al complejo clonal 320 de carácter pandémico y asociado a resistencia antimicrobiana. Además, casi todas las infecciones invasoras por serotipo 19A en niños se han dado en pacientes con esquema completo de vacunación PCV10. Los cambios epidemiológicos presentados indican la emergencia de infecciones invasoras por el serotipo 19A y la necesidad de controlar este problema con el cambio de la vacuna PCV10 a la vacuna PCV13 que contiene el serotipo 19A.
Inclusion of the 10-valent pneumococcal conjugated vaccine (PCV10) in the Chilean infant vaccination Program in 2011 was followed by a reduction of hospital admissions and pneumonia-related deaths in this age group. However, a progressive increase of serotype 19A pneumococcal isolates (not included in PCV10) has been observed. According to the analysis of pneumococcal strains performed by the national reference laboratory of the Institute of Public Health as part of a national surveillance on invasive pneumococcal infections, the relative proportion of serotype 19A isolates increased from <5% before 2010 to 12-23% in years 2014-2015. Serotype 19A represented 4-8% of the isolates in the pre-vaccine era among children less than 2 years, increasing to 25% during 2014. This increase has been documented in two-thirds of the national territory. Aimong children <5 years of age, 25% of 19A serotype isolates from non-meningeal infections were penicillin resistant wheras from meningeal infections near 100% were penicillin resistant. Genetic analysis indicates that 48% of these 19A strains belong to clonal complex 320, recognized for its pandemic potential and high antimicrobial resistance. Among children, most invasive infections secondary to serotype 19A have occurred in patients fully vaccinated with PCV10. These epidemiological changes indicate an increase in invasive pneumococcal infections by serotype 19A in Chile and the need to control this problem by changing the current PCV10 for the PCV13 vaccine containing serotype 19A.
Subject(s)
Humans , Child , Pneumococcal Infections/prevention & control , Streptococcus pneumoniae/classification , Vaccination/standards , Pneumococcal Vaccines/therapeutic use , Advisory Committees/standards , Chile , Drug Resistance, Bacterial , SerogroupABSTRACT
Invasive pneumococcal disease (IPD) remains as an important cause of morbidity in the world and in our country, while in Chile the incidence has decreased after the incorporation of the 10 valent pneumococcal conju-gate vaccine, in the routine infant inmunization schedule (EPI). One of the expected effects of the program after vaccination with 10-valent pneumococcal vaccine is the likely replacement serotype phenomenon that means the presence of ENI caused by serotypes not included in the vaccine. In this context, we present the case of a child with pneumococcal meningitis caused by serotype 19 A of fatal course. The occurrence of ENI in a later stage of pneumococcal vaccine incorporation in Chile reinforces the importance of active surveillance, in order to know in detail the impact of vaccination, distribution of circulating serotypes and their correlation with the different clinical disease and their severity.
La enfermedad neumocóccica invasora (ENI) sigue siendo una causa importante de morbilidad en el mundo y en nuestro país, si bien en Chile la incidencia ha disminuido luego de la incorporación de la vacuna neumocóccica conjugada 10-valente al Programa Nacional de Inmunizaciones (PNI). Uno de los efectos esperables luego de la vacunación programática con la vacuna antineumocóccica 10-valente es el probable fenómeno de reemplazo, que corresponde a la presencia de ENI por serotipos no incluidos en la vacuna. En este contexto, se presenta el caso de un pre-escolar con meningitis neumocóccica causada por el serotipo 19 A, de curso fatal. La presencia de casos de ENI en una etapa posterior a la implementación de la vacuna anti-neumocóccica en el PNI de Chile, demuestra la importancia de realizar una vigilancia activa, con el objetivo de conocer en forma detallada el impacto de la vacunación, la distribución de los serotipos circulantes y su correlación con los diferentes cuadros clínicos y su evolución.
Subject(s)
Child, Preschool , Humans , Male , Meningitis, Pneumococcal/diagnosis , Streptococcus pneumoniae/genetics , Fatal Outcome , Meningitis, Pneumococcal/drug therapy , Pneumococcal Vaccines/immunology , Streptococcus pneumoniae/immunology , Streptococcus pneumoniae/isolation & purificationABSTRACT
OBJECTIVE: To describe the epidemiology, clinical syndromes and microbiological characteristics of serotype 19A as the main cause of invasive pneumococcal disease (IPD) in children admitted to a tertiary hospital in Spain. METHODS: A retrospective (1998-2004) and prospective (2005-2009) study was conducted on children with IPD produced by serotype 19A. The study was divided into three periods (P): P1 (1998-2001) when PCV7 had not been commercialized; P2 (2002-2005) with 40% vaccine coverage among children; and P3 (2006-2009) when the vaccine was added to the Childhood Immunization Schedule in Madrid. RESULTS: A total of 155 isolates of Streptococcus pneumoniae (SP) producing IPD were analysed, with 21 of them being serotype 19A (14%). An increased prevalence of serotype 19A was found: 2/45 cases (4.4%) in P1, 3/41 cases (7.3%) in P2 and 16/69 cases (23.2%) in P3. It occurred mostly in children younger than 2 years (16/21; 76%). This serotype was the main cause of meningitis (5/20; 25%), pleural empyema (3/22; 14%) and bacteraemic mastoiditis (2/4; 50%). Thirteen isolates (61.5%) had an MIC ≥ 0.12µ/ml for penicillin in extra-meningeal infections, and 3 of the 5 isolates causing meningitis (60%) had an MIC ≥ 1µ/ml for cefotaxime. CONCLUSIONS: Serotype 19A was the main causal agent of IPD in the PCV7 era (P3), with high antibiotic resistance rates. This serotype was responsible for all types of IPD, being the main cause of meningitis.
Subject(s)
Pneumococcal Infections/epidemiology , Pneumococcal Infections/prevention & control , Pneumococcal Vaccines , Streptococcus pneumoniae , Humans , Immunization Schedule , Incidence , Infant , Prospective Studies , Retrospective Studies , Serotyping , Streptococcus pneumoniae/classification , Time FactorsABSTRACT
La aplicación de la vacuna PCV7 en algunos países ha determinado un aumento significativo de neumococos del serotipo 19A y este hecho ha llevado a una atenuación del impacto inicial logrado en términos de prevención de enfermedades neumocócicas invasivas. Los objetivos de este trabajo fueron: (a) describir la frecuencia de los neumococos 19A, antes de la vacunación antineumocócica masiva, en niños con OMA desde la óptica parcial de un solo hospital de la ciudad de Buenos Aires, (b) estudiar su vinculación a casos de recurrencias y (c) su sensibilidad a los antimicrobianos. Se aislaron 133 neumococos, 126 de los cuales resultaron viables para poder realizar su identificación a nivel de tipo y los estudios correspondientes de sensibilidad a los antibióticos. Los serotipos más prevalentes fueron el 14 (14,3%) y el 19A (11,9%). Ocho de los 15 aislados de S. pneumoniae 19A presentaron sensibilidad disminuida a la penicilina, lo que representó el 22,2% de los neumococos no sensibles provenientes de OMA. El serotipo 19A estuvo involucrado en 3 de los 12 casos de recurrencias por S. pneumoniae. Probablemente la nueva vacuna 13-valente, la única conjugada que contiene antígenos contra el neumococo 19A, pueda impedir su incremento tanto en OMA como en enfermedades invasivas.
In several countries administration of PCV7vaccine has cau-sed a significant increase in 19A serotype pneumococci.This effect has diminished the initial impact on invasive pneumococcal infection prevention. The aims of the present study were: (a) to describe the incidence of 19A pneumococci in children with acute otitis media (AOM), beforethe massive administration of pneumococcal vaccines, fromthe scope of a single pediatric hospital in the city of Buenos Aires, (b) to study their relation to recurrences, and (c) their antimicrobial susceptibility. One hundred and thirty-three pneumococci were isolated from children with AOM; 126 of these were viable to further identify pneumococcal serotypes and determine antimicrobial susceptibility. The most prevalent serotypes were 14 (14.3%) and 19A (11.9%). Eightout of the 15 19A serotype pneumococcal isolates showed diminished susceptibility to penicillin, accounting for 22.2% of non-susceptible pneumococci from AOM. Serotype 19A was involved in 3 out of 12 cases of recurrent AOM due to S. pneumoniae. The new 13-valent vaccine, containing antibodies against 19A pneumococci, may prevent its increasing incidence rate both in AOM and in other invasive infections.
