Etiology of Bacterial Meningitis en Children between 3 month and 5 years of age in the Instituto Nacional de Salud del Niño, Lima – Perú, 2003 to 2008

Abstract

Objective: In the latest study of Bacterial Meningitis done at Instituto Nacional de Salud del Niño prior to the introduction of the Haemophilus influenzae type b (Hi”b”) conjugate vaccine, it was found that Hi”b” infections were the leading cause of meningitis, affecting mainly children under 24 months of age. (4) Our main objective was to determine the etiology of bacterial meningitis and the number of cases caused by Haemophilus influenzae type b before and after the introduction of the haemophilus influenzae type b (Hib) conjugate vaccine in the national immunization program.

Methods: In our descriptive, longitudinal, retrospective study, we analyzed medical records of 106 inpatients children at Instituto Nacional de Salud del Niño between 3 months and 5 years of age with a diagnosis of bacterial meningitis, from 2003 to 2008. We divided the records in two, the first period, prior to the introduction of the Haemophilus influenzae type b (Hib) conjugate vaccine (2003 - 2004) and the second after the introduction of the vaccine into the PAI (Programa Ampliado de Inmunizacion) (2005 - 2008). We evaluated the characteristics of CSF using the comparative table of the European Journal of Neurology, and the "Bacterial Meningitis Score," after that, we proceeded to review the culture to confirm the presence of a specific agent.

Results: The rate of bacterial meningitis declined 30% compared to the previous study done at Instituto Nacional de Salud del Niño. Incidences remain higher for patients under 24 months of age. Haemophilus influenzae type b accounted for 29.2% cases of bacterial meningitis and Streptococcus pneumoniae 13.2%. During the period prior to the introduction of the vaccine, Haemophilus influenzae type b was responsible for 68.29% of cases, in contrast to the period following the introduction of the vaccine, constituting 18.75 %. Streptococcus pneumoniae became the predominant pathogen of bacterial meningitis since the introduction of the Hib vaccine.

Conclusions: The rate of bacterial meningitis has decreased from 2002 to 2008.After the introduction of the H. influenza type b conjugate vaccine, bacterial meningitis caused by H. influenza type b was decreased. The most frequent etiologic agent of bacterial meningitis in children under 5 years of age was Streptococcus pneumoniae.