Laboratory-based surveillance of Streptococcus pneumoniae invasive disease in children in 10 Latin American countries: a SIREVA II project, 2000-2005.

BACKGROUND: For the last 14 years the Pan American Health Organization has been promoting surveillance of invasive pneumococcal disease in Latin American children for better understanding of the disease tendencies regarding capsular types circulation in each country and susceptibility to antimicrobials. METHODS: Laboratory-based surveillance data from 10 Latin American countries collected from 2000 to 2005 were analyzed, including serotype distribution and susceptibility to beta-lactam antibiotics. RESULTS: Although 61 different capsular types were identified during the 6-year surveillance, 13 serotypes accounted for 86% of all isolates. These were consistently the most prevalent throughout the study period with serotype 14 predominating. Diminished susceptibility to penicillin was detected in 38% of all Streptococcus pneumoniae isolates, with the highest prevalence in Dominican Republic and Mexico. Decreased susceptibility to penicillin increased in Brazil and Colombia whereas decreased high resistance rates was recorded in Chile. CONCLUSIONS: These data indicate that 10 countries of the Region continue to have high quality laboratory-based surveillance for pneumococcal disease thus generating valuable information so that healthcare decision makers may prioritize interventions. The heptavalent vaccine will potentially cover from 52.4% to 76.5% of strains causing invasive pneumococcal disease and the 13 valent from 76.7% to 88.3%.

Molecular characterization of invasive serogroup Y Neisseria meningitidis strains isolated in the Latin America region.

OBJECTIVES: To improve the understanding of serogroup Y invasive meningococcal disease (IMD) in Latin America, particularly IMD molecular epidemiology; 166 Y serogroup isolates received at the National Reference Laboratories of Argentina, Brazil, Chile, Colombia, and Costa Rica during 2000-2006 were characterized by their molecular markers. METHODS: This analysis included serological assays to determine serogroup/serotype/serosubtype, DNA sequencing and genotyping of the porB and/or porA genes, multilocus sequence typing (MLST) and fetA allele determination. RESULTS: Sixteen different antigenic combinations were observed. Sixty-two (37.3%) isolates were NT:P1.5 and 36 (21.7%) isolates were 14:NST. Thirty-two different STs appeared, but 3 STs (ST-1624, ST-23, and ST-5770) accounted for 69.9% (116) of the strains. Most of the IMD isolates belonged to the ST-23, ST-167 clonal complexes or the group composed by ST-5770 and related STs. CONCLUSIONS: Isolates obtained in Colombia and Costa Rica were similar to that of the United States, in that most sequence types belonged to the ST-23 clonal complex. IMD isolates found in Argentina appear to be the result of an independent event and did not spread from nearby countries, being the sequence type ST-1624 (ST-167 clonal complex) the most frequently found. We were unable to correlate an antigenic shift of outer membrane proteins with an increase of serogroup Y meningococcal cases in our collection of isolates.

[Surveillance of Haemophilus influenzae serotypes and antimicrobial resistance in Colombia, 1994-2002]. / Vigilancia de los serotipos y susceptibilidad antimicrobiana de Haemophilus influenzae en Colombia, 1994-2002.

Invasive disease caused by Haemophilus influenzae serotype b results in high rates of morbidity and mortality among children. In 1994, the Microbiology Group at the Instituto Nacional de Salud (Colombia) initiated a program to detect antimicrobial resistance in H. influenzae. Invasive isolates were collected by hospitals and public health laboratories as part of surveillance programs for acute respiratory infections and acute bacterial meningitis. To determine the evolution of serotypes and antimicrobial resistance patterns, invasive H. influenzae isolates collected from 1994 to 2002 were compared, and the impact of Hib conjugated vaccine in Colombia was reassessed. The analysis included 683 isolates, 379 (55.5%) were recovered from male patients, 370 (54.2%) from children under one year, 227 (33.2%) from children aged 1 to 5, 19 (2.8%) from children aged 6 to 14, and 38 (5.6%) from children over 14 years; 29 (4.2%) with no age data. Clinical classification recorded 493 (72.2%) of the samples were from patients with meningitis, 181 (26.5%) with pneumonia, and 9 (0.9%) with other diseases. Eighty five percent of isolates corresponded to H. influenzae serotype b, 12.9% were non capsular, and 2.0% corresponded to other serotypes (10 a, 1 d, 1 e and 2 f). Of the total number of isolates, 12.0% produced beta lactamase, 13.9% were resistant to ampicillin, 12.7% to trimethoprim sulfamethoxazole (SXT), 5.4% to chloramphenicol, 1% to cefuroxime. All isolates were susceptible to ceftriaxone. During the 10-year period, resistance to SXT increased from 5% to 13%. A significant decrease in meningitis cases was detected among children under one-year old and in the 1 to 5 age group. Before introducing the vaccine, an annual average of 43 and 23 isolates for each of these groups were received. During 2002, 10 and 6 isolates, respectively, were received for each group. Surveillance of invasive H. influenzae isolates has allowed the evaluation of Hib vaccine impact, as well as the detection of an increase of non-capsular isolates, and changes in resistance patterns.

Vigilancia de los serotipos y susceptibilidad antimicrobiana de Haemophilus influenzae en Colombia, 1994-2002 / Surveillance of Haemophilus influenzae serotipes and antimicrobial resistance in Colombia, 1994-2002

La enfermedad invasora causada por Haemophilus influenzae, serotipo b, ha sido una de las mayores causas de morbilidad y mortalidad en la población infantil; afortunadamente, en algunos países con amplia cobertura de la vacuna conjugada esta situación ha cambiado. En 1994 se inició en el Grupo de Microbiología un programa de vigilancia de la susceptibilidad antimicrobiana y de los serotipos de aislamientos invasores de H. influenzae, remitidos por los hospitales y Laboratorios de Salud Pública del país como componente de los programas de vigilancia en red de infección respiratoria aguda y meningitis bacteriana aguda. El objetivo de este trabajo fue determinar la evolución de los serotipos y los patrones de susceptibilidad antimicrobiana de los aislamientos invasores de H. influenzae obtenidos de 1994 al 2002 y realizar un nuevo análisis sobre el impacto de la vacuna conjugada de H. influenzae, serotipo b, en Colombia. De 1994 a 2002 se han estudiado 683 aislamientos; 379 (55,5 por ciento) de pacientes del género masculino; 370 (54,2 por ciento) de menores de 1 año; 227 (33,2 por ciento) de 1 a 5 años; 19 (2,8 por ciento) de 6 a 14 años; 38 (5,6 por ciento) de mayores de 14 años, y de 29 (4,2 por ciento) no se tenía el dato de la edad; 493 (72,2 por ciento) fueron recuperados de pacientes con meningitis, 181 (26,5 por ciento) de neumonía y 9 (0,9 por ciento) de otras enfermedades. El 85,1 por ciento de los aislamientos fueron H. influenzae, serotipo b, 12,9 por ciento no capsulares y 2,0 por ciento de otros serotipos (10 a, 1 d, 1 e y 2 f). Del total de aislamientos, 12 por ciento fueron productores de beta-lactamasa; 13,9 por ciento resistentes a ampicilina; 12,7 por ciento, a trimetoprim sulfametoxazol (SXT); 5,4 por ciento, cloranfenicol, y 1 por ciento de cefuroxima; todos fueron sensibles a ceftriaxona. Durante este período se observó un incremento en la resistencia de los aislamiento a SXT (5 por ciento al 13 por ciento), pero la diferencia no fué estadísticamente significativa (p=0,1). Con la vigilancia se pudo determinar una disminución significativa de los casos de meningitis...

Impacto de Streptococcus pneumoniae en las neumonias del niño latinoamericano / Impact of Streptococcus pneumoniae in Latin American children

La neumonia adquirida en la comunidad es una de las principales causas de morbilidad y mortalidad en la infancia. Estudios realizados en paises en desarrollo indican que los cuadros de neumonia mas graves se asocian a causas bacterianas, con predominio de Streptococcus pneumoniae, seguido por Haemophilus influenzae tipo b. El manejo de esas infecciones en los menores de 2 años se ve dificultado por la carencia de vacunas apropiadas y por la disminucion de la susceptibilidad de S. pneumoniae a la penicilina y a otros antibioticos. En 1993, por iniciativa del Sistema Regional de Vacunas (SIREVA) de la Organizacion Panamericana de la Salud y con la financiacion de la Agencia Canadiense para el Desarrollo Internacional (Canadian International Development Agency: (CIDA), se diseño un estudio para identificar los tipos capsulares de S. pneumoniae que causan enfermedad invasora en los niños latinoamericanos menores de 5 años, con el proposito de determinar tanto la composicion ideal de una vacuna conjugada que pudiera emplearse en la Region como la susceptibilidad a la penicilina de los aislados de S. pneumoniae. La iniciativa fue aceptada por Argentina, Brasil, Colombia, Chile, Mexico y Uruguay. En este informe se analiza la informacion sobre la neumonia por S. pneumoniae generada en los paises participantes. Se captaron 3.393 niños con infecciones sistemicas por S. pneumoniae, de las cuales 1.578 correspondian a neumonias. El analisis se concentro en los 1.409 casos de neumonia de Argentina, Brasil, Colombia, Mexico y Uruguay. La distribucion por edades evidencio un franco predominio de los menores de 2 años (63.8 por ciento). Se identificaron 12 tipos capsulares prevalentes, de los cuales los serotipos 14, 5 y 1 ocuparon los tres primeros lugares en la mayoria de los paises

Community-acquired pneumonia is one of the leading causes of infant morbidity and mortality. Studies conducted in developing countries indicate that the most serious symptoms of pneumonia are associated with bacterial causes, mainly Streptococcus pneumoniae, followed by Haemophilus influenzae type b. Managing those infections in children under two years of age is hindered by the lack of appropriate vaccines and by the decreased susceptibility of S. pneumoniae to penicillin and other antibiotics. In 1993, at the initiative of the Regional System for Vaccines of the Pan American Health Organization, and with funding from the Canadian International Development Agency, a study was designed to identify the S. pneumoniae capsular types that cause invasive disease in Latin American children under 5 years of age. The objective of the study was to determine the ideal composition of a conjugate vaccine that could be used in Latin America, and the penicillin susceptibility of the S. pneumoniae isolates. The initiative was undertaken in Argentina, Brazil, Chile, Colombia, Mexico, and Uruguay. This report analyzes the information that the participating countries generated on pneumococcal pneumonia. A total of 3 393 children were found with systemic S. pneumoniae infections, of which 1 578 corresponded to pneumonias. The analysis focused on 1 409 cases of pneumonia in Argentina, Brazil, Colombia, Mexico, and Uruguay. Of the children, 63.8% of them were under two years of age. Twelve prevalent capsular types were identified, of which serotypes 14, 5, and 1 were the three most common in the majority of the countries. At the beginning of the study the highest level of penicillin resistance was found in Mexico (47.0%), and the lowest in Colombia (12.1%). Over the 1993­1998 period, resistance to penicillin increased in the five countries. Penicillin resistance was associated with a small number of capsular serotypes, mainly 14 and 23F. The first of those serotypes was resistant to penicillin and to trimethoprim-sulfamethoxazole, and the second was multiresistant. The frequency of resistance to trimethoprim-sulfamethoxazole was high in all of the countries; Argentina had the highest level, 58.0%. A decrease in susceptibility to chloramphenicol was uncommon, except in Colombia, where there was a resistance level of 23.4%. Resistance to erythromycin was low in all the countries, and all the isolates were susceptible to vancomycin.