Indirect impact of PCV10 children vaccination on the serotype distribution and antimicrobial resistance of Streptococcus pneumoniae causing invasive disease in adults over 50 in Colombia, 2005-2019: Observational analysis.

INTRODUCTION: The introduction of pneumococcal conjugate vaccine (PCV) into childhood vaccination programmes has reduced the prevalence of vaccine serotypes (VTs) that cause invasive pneumococcal disease (IPD) in children. In the elderly population, an impact has also been seen through indirect protection (herd effect). The aim of this study was to estimate the changes in serotype distribution and antimicrobial susceptibility of Streptococcus pneumoniae isolates recovered from adult IPD and to evaluate the indirect effect of immunization with PCV10 based on laboratory records by analyzing the period from 2005 to 2019 for six years before and eight years after the universal PCV10 administration to Colombian children. METHODS: A total of 2204 S. pneumoniae isolates from adults (≥50 years) with IPD were analyzed. The analysis examined the percentage changes in proportions (prevalence) and percentage variations in population rates (annual reported rates - ARR) of VTs between the pre-PCV10 (2005-2009) and post-PCV10 (2015-2019) periods. RESULTS: The findings were (1) evidence of a significant percentage decrease of pneumococcal VT10 causing IPD in adults (50% pre-PCV10 and 16% post-PCV10); (2) significant increase of serotype 19A (from 1.6% to 14.8%) and less important increase of serotype 3 (from 10.5% to 14.5%) and non-vaccine serotypes (NVT) (from 21.4% to 38.4%) non-significant; and (3) meningitis and non-meningitis multidrug resistant isolates associated with serotype 19A. An improvement in the surveillance system is associated with the immunization of children, as noted by the increased ARRs across the analysis period. CONCLUSIONS: Our results show the indirect impact of PCV10 vaccination in children on the VT10 distribution and antimicrobial resistance of S. pneumoniae causing IPD in Colombian adults over 50 when comparing the pre-PCV10 (2005-2009) and post-PCV10 (2015-2019) periods.

Population structure of Neisseria meningitidis ST-9493 identified in Colombian isolates.

INTRODUCTION: Neisseria meningitidis is associated with invasive infections causing high mortality rates. The objective of this study was to describe the population structure of Colombian invasive isolates with ST-9493, a potentially emerging clonal group in the country. METHODS: The complete genomes of 34 invasive isolates of serogroup B with ST-9493 and its variants at one or two loci were sequenced by Illumina to describe the phenotypic and genotypic characteristics of these isolates. RESULTS: The relationship of a clonal group associated with ST-136 CC41/44 was phylogenetically established, identifying two main clades composed of isolates from an outbreak or endemic. The most frequent alleles and peptides included porA 17, porB 44, fHbp 2.24, NHBA 10, and the FetA F5-17 variant. Most of the isolates were susceptible to the antibiotics evaluated. CONCLUSION: This study shows that meningococcal isolates with ST-9493 are an autochthonous clonal group with population dynamics and the capacity to cause endemic and epidemic meningococcal disease in Colombia.

Sentinel surveillance for bacterial pneumonia and meningitis in children under the age of 5 in a tertiary pediatric hospital in Colombia - 2016. / Vigilancia centinela de neumonías y meningitis bacterianas en menores de 5 años en un hospital pediátrico de tercer nivel en Colombia - 2016

INTRODUCTION: Bacterial pneumonia and meningitis are vaccine-preventable diseases. Sentinel surveillance provides relevant information about their behavior. OBJECTIVE: To present the data from sentinel surveillance carried out at the Fundación HOMI, Fundación Hospital Pediátrico La Misericordia in 2016. MATERIALS AND METHODS: We conducted a descriptive study from January 1 to December 31, 2016, on the daily surveillance of patients under 5 years of age diagnosed with pneumonia or bacterial meningitis according to PAHO's definitions. We identified the microorganisms using the automated VITEKTM 2 system. Bacterial isolates were sent to the Microbiology Group at the Colombian Instituto Nacional de Salud for confirmation, serotyping, phenotypic, and genotypic characterization. Antimicrobial susceptibility profiles were established. RESULTS: From 1,343 suspected cases of bacterial pneumonia, 654 (48.7%) were probable, 84% had complete Hib vaccination schedules, and 87% had complete pneumococcal vaccination schedules for age. Blood culture was taken in 619 (94.6%) and 41 (6.6%) were positive while S. pneumoniae was isolated in 17 (41%) of them. The most frequent serotype was 19A in five cases (29.4%), and four 19A serotypes were associated with the reference isolate ST320. The incidence rate of probable bacterial pneumonia was 7.3 cases/100 hospitalized patients, and lethality was 2.1%. As for bacterial meningitis, 22 suspected cases were reported, 12 (54%) were probable, four (33%) were confirmed: two by Escherichia coli and two by group C N. meningitidis. The incidence of probable bacterial meningitis was 0.14 cases/100 hospitalized patients. CONCLUSION: Streptococcus pneumoniae serotypes 19A and 3 were the most frequent cause of pneumonia. Spn19A is related to the multi-resistant clone ST320. Strengthening and continuing this strategy will allow understanding the impact of vaccination.

Introducción. La neumonía y la meningitis bacterianas son enfermedades inmunoprevenibles; la vigilancia centinela aporta información relevante acerca de su comportamiento. Objetivo. Presentar los resultados de la vigilancia centinela de neumonía y meningitis llevada a cabo en la HOMI, Fundación Hospital Pediátrico La Misericordia. Materiales y métodos. Se hizo un estudio descriptivo entre el 1 de enero y el 31 diciembre del 2016, de la vigilancia diaria de pacientes menores de 5 años con diagnóstico de neumonía o meningitis bacteriana, según las definiciones de la Organización Panamericana de la Salud (OPS). Los microorganismos fueron identificados usando el sistema automatizado VITEK TM2. Los aislamientos se enviaron al grupo de microbiología del Instituto Nacional de Salud para confirmación, serotipificación, y caracterización genotípica y fenotípica. Asimismo, se establecieron los perfiles de sensibilidad antimicrobiana. Resultados. De 1.343 casos sospechosos de neumonía bacteriana, 654 (48,7 %) fueron probables, el 84 % tenía el esquema de vacunación completo para la edad contra Haemophilus influenzae de tipo b, y el 87 %, contra neumococo. En 619 (94,6 %) pacientes se hizo hemocultivo y 41 (6,6 %) fueron positivos. S. pneumoniae se aisló en 17 (41 %) casos. El serotipo más frecuente fue el 19A, en cinco pacientes (29,4 %), en tanto que cuatro aislamientos de spn19A fueron relacionados con el clon ST320. La tasa de incidencia de neumonía bacteriana probable fue de 7,3 casos/100 pacientes hospitalizados. La letalidad fue de 2,1 %. Hubo 22 casos sospechosos de meningitis bacteriana, 12 (54 %) probables, y cuatro (33 %) confirmados: dos por Escherichia coli y dos por Neisseria meningitidis del grupo C. La incidencia de meningitis bacteriana probable fue de 0,14/100 pacientes hospitalizados. Conclusión. Los serotipos 19A y 3 de S. pneumoniae fueron la causa más frecuente de neumonía. El Spn19A se relacionó con el clon ST320 mulitirresistente. El fortalecimiento continuo de la vigilancia centinela permitirá entender el impacto de la vacunación.

Cellulose biosynthesis using simple sugars available in residual cacao mucilage exudate.

Worldwide only 8% of the biomass from harvested cacao fruits is used, as cacao beans, in chocolate-based products. Cacao mucilage exudate (CME), a nutrient-rich fluid, is usually lost during cacao beans fermentation. CME's composition and availability suggest a potential carbon source for cellulose production. CME and the Hestrin and Schramm medium were used, and compared, as growth media for bacterial cellulose (BC) production with Gluconacetobacter xylinus. CME can be used to produce BC. However, the high sugar content, low pH, and limited nitrogen sources in CME hinder G. xylinus growth affecting cellulose yields. BC production increased from 0.55 ± 0.16 g L-1 up to 13.13 ± 1.09 g L-1 after CME dilution and addition of a nitrogen source. BC production was scaled up from 30 mL to 15 L, using lab-scale experiments conditions, with no significant changes in yields and production rates, suggesting a robust process with industrial possibilities.

Sentinel surveillance for bacterial pneumonia and meningitis in children under the age of 5 in a tertiary pediatric hospital in Colombia - 2016 / Vigilancia centinela de neumonías y meningitis bacterianas en menores de 5 años en un hospital pediátrico de tercer nivel en Colombia - 2016

Abstract | Introduction: Bacterial pneumonia and meningitis are vaccine-preventable diseases. Sentinel surveillance provides relevant information about their behavior. Objective: To present the data from sentinel surveillance carried out at the Fundación HOMI, Fundación Hospital Pediátrico La Misericordia in 2016. Materials and methods: We conducted a descriptive study from January 1 to December 31, 2016, on the daily surveillance of patients under 5 years of age diagnosed with pneumonia or bacterial meningitis according to PAHO's definitions. We identified the microorganisms using the automated VITEKTM 2 system. Bacterial isolates were sent to the Microbiology Group at the Colombian Instituto Nacional de Salud for confirmation, serotyping, phenotypic, and genotypic characterization. Antimicrobial susceptibility profiles were established. Results: From 1,343 suspected cases of bacterial pneumonia, 654 (48.7%) were probable, 84% had complete Hib vaccination schedules, and 87% had complete pneumococcal vaccination schedules for age. Blood culture was taken in 619 (94.6%) and 41 (6.6%) were positive while S. pneumoniae was isolated in 17 (41%) of them. The most frequent serotype was 19A in five cases (29.4%), and four 19A serotypes were associated with the reference isolate ST320. The incidence rate of probable bacterial pneumonia was 7.3 cases/100 hospitalized patients, and lethality was 2.1%. As for bacterial meningitis, 22 suspected cases were reported, 12 (54%) were probable, four (33%) were confirmed: two by Escherichia coli and two by group C N. meningitidis. The incidence of probable bacterial meningitis was 0.14 cases/100 hospitalized patients. Conclusion: Streptococcus pneumoniae serotypes 19A and 3 were the most frequent cause of pneumonia. Spn19A is related to the multi-resistant clone ST320. Strengthening and continuing this strategy will allow understanding the impact of vaccination.

Resumen | Introducción. La neumonía y la meningitis bacterianas son enfermedades inmunoprevenibles; la vigilancia centinela aporta información relevante acerca de su comportamiento. Objetivo. Presentar los resultados de la vigilancia centinela de neumonía y meningitis llevada a cabo en la HOMI, Fundación Hospital Pediátrico La Misericordia. Materiales y métodos. Se hizo un estudio descriptivo entre el 1 de enero y el 31 diciembre del 2016, de la vigilancia diaria de pacientes menores de 5 años con diagnóstico de neumonía o meningitis bacteriana, según las definiciones de la Organización Panamericana de la Salud (OPS). Los microorganismos fueron identificados usando el sistema automatizado VITEK TM2. Los aislamientos se enviaron al grupo de microbiología del Instituto Nacional de Salud para confirmación, serotipificación, y caracterización genotípica y fenotípica. Asimismo, se establecieron los perfiles de sensibilidad antimicrobiana. Resultados. De 1.343 casos sospechosos de neumonía bacteriana, 654 (48,7 %) fueron probables, el 84 % tenía el esquema de vacunación completo para la edad contra Haemophilus influenzae de tipo b, y el 87 %, contra neumococo. En 619 (94,6 %) pacientes se hizo hemocultivo y 41 (6,6 %) fueron positivos. S. pneumoniae se aisló en 17 (41 %) casos. El serotipo más frecuente fue el 19A, en cinco pacientes (29,4 %), en tanto que cuatro aislamientos de spn19A fueron relacionados con el clon ST320. La tasa de incidencia de neumonía bacteriana probable fue de 7,3 casos/100 pacientes hospitalizados. La letalidad fue de 2,1 %. Hubo 22 casos sospechosos de meningitis bacteriana, 12 (54 %) probables, y cuatro (33 %) confirmados: dos por Escherichia coli y dos por Neisseria meningitidis del grupo C. La incidencia de meningitis bacteriana probable fue de 0,14/100 pacientes hospitalizados. Conclusión. Los serotipos 19A y 3 de S. pneumoniae fueron la causa más frecuente de neumonía. El Spn19A se relacionó con el clon ST320 mulitirresistente. El fortalecimiento continuo de la vigilancia centinela permitirá entender el impacto de la vacunación.

Streptococcus pneumoniae serotype 3 genotypes in invasive isolates from Colombia. / Genotipos del serotipo 3 de Streptococcus pneumoniae en aislamientos invasivos en Colombia

INTRODUCTION: Streptococcus pneumoniae serotype 3 is an important cause of pneumonia, bacteremia, and meningitis. OBJECTIVE: To establish the circulating genotypes of S. pneumoniae serotype 3 isolates recovered from the invasive disease between 1994 to 2015 in Colombia. MATERIALS AND METHODS: Of the 365 S. pneumoniae serotype 3 isolates recovered through the laboratory national surveillance program, 117 isolates were analyzed. Pulsed-field gel electrophoresis was used for genotyping, and multilocus sequence typing was determined in representative isolates. RESULTS: The frequency of this serotype increased from 2.7% between 1994 and 1998 to 9.1% between 2011 and 2015 (p=0.000); 91.7% of the isolates showed a genetic similarity greater than 77% and were related to the Netherlands3-31(PMEN31) clone CC180. Several subtypes were identified, two of which showed antimicrobial resistance. CONCLUSION: In Colombia, the pneumococcal population of the capsular type 3 shows a continuous and homogeneous circulation relating to the clonal group ST-180.

Introducción. El serotipo 3 de Streptococcus pneumoniae es una causa importante de neumonía, bacteriemia y meningitis. Objetivo. Establecer los genotipos circulantes de aislamientos del serotipo 3 de S. pneumoniae recuperados de muestras de enfermedad invasiva de 1994 a 2015 en Colombia. Materiales y métodos. Se analizaron 117 de los 365 aislamientos del serotipo 3 de S. pneumoniae recuperados del programa nacional de vigilancia por el laboratorio. El genotipo se estableció con electroforesis en gel de campo pulsado y la tipificación se llevó a cabo mediante secuenciación multilocus en aislamientos representativos. Resultados. La frecuencia de este serotipo aumentó de 2,7 % entre 1994 y 1998 a 9,1 % entre 2011 y 2015 (p=0,000). El 91,7 % de los aislamientos evidenció una similitud genética superior al 77 % y se relacionó con el clon CC180 de Netherlands3-31 (PMEN31). Se identificaron varios subtipos, dos de los cuales mostraron resistencia a los antimicrobianos. Conclusión. En Colombia, la población neumocócica del tipo capsular 3 tiene una circulación continua y homogénea relacionada con el grupo clonal ST-180.

Streptococcus pneumoniae serotype 3 genotypes in invasive isolates from Colombia / Genotipos del serotipo 3 de Streptococcus pneumoniae en aislamientos invasivos en Colombia

Abstract | Introduction: Streptococcus pneumoniae serotype 3 is an important cause of pneumonia, bacteremia, and meningitis. Objective: To establish the circulating genotypes of S. pneumoniae serotype 3 isolates recovered from the invasive disease between 1994 to 2015 in Colombia. Materials and methods: Of the 365 S. pneumoniae serotype 3 isolates recovered through the laboratory national surveillance program, 117 isolates were analyzed. Pulsed-field gel electrophoresis was used for genotyping, and multilocus sequence typing was determined in representative isolates. Results: The frequency of this serotype increased from 2.7% between 1994 and 1998 to 9.1% between 2011 and 2015 (p=0.000); 91.7% of the isolates showed a genetic similarity greater than 77% and were related to the Netherlands3-31(PMEN31) clone CC180. Several subtypes were identified, two of which showed antimicrobial resistance. Conclusion: In Colombia, the pneumococcal population of the capsular type 3 shows a continuous and homogeneous circulation relating to the clonal group ST-180.

Resumen | Introducción. El serotipo 3 de Streptococcus pneumoniae es una causa importante de neumonía, bacteriemia y meningitis. Objetivo. Establecer los genotipos circulantes de aislamientos del serotipo 3 de S. pneumoniae recuperados de muestras de enfermedad invasiva de 1994 a 2015 en Colombia. Materiales y métodos. Se analizaron 117 de los 365 aislamientos del serotipo 3 de S. pneumoniae recuperados del programa nacional de vigilancia por el laboratorio. El genotipo se estableció con electroforesis en gel de campo pulsado y la tipificación se llevó a cabo mediante secuenciación multilocus en aislamientos representativos. Resultados. La frecuencia de este serotipo aumentó de 2,7 % entre 1994 y 1998 a 9,1 % entre 2011 y 2015 (p=0,000). El 91,7 % de los aislamientos evidenció una similitud genética superior al 77 % y se relacionó con el clon CC180 de Netherlands3-31 (PMEN31). Se identificaron varios subtipos, dos de los cuales mostraron resistencia a los antimicrobianos. Conclusión. En Colombia, la población neumocócica del tipo capsular 3 tiene una circulación continua y homogénea relacionada con el grupo clonal ST-180.

Molecular characterization of Neisseria meningitidis isolates recovered from patients with invasive meningococcal disease in Colombia from 2013 to 2016.

BACKGROUND: Neisseria meningitidis is a significant cause of morbidity and mortality worldwide. Meningococcal isolates have a highly dynamic population structure and can be phenotypically and genetically differentiated into serogroups and clonal complexes. The aim of this study was to describe the phenotypic and genotypic characteristics of invasive isolates recovered in Colombia from 2013 to 2016. METHODOLOGY: A total of 193 invasive isolates were analyzed. Phenotypic and genotypic characteristics were determined by serotyping, antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing. RESULTS: Based on the results, meningococcal serogroups C, B and Y were responsible for 47.9%, 41.7%, and 9.4% of cases, respectively, and the distribution of serogroups B and C changed over time. Fifteen clonal groups and 14 clonal complexes (cc) were identified by PFGE and genome sequencing. The main clonal group included serogroup B isolates with sequence type (ST)-9493 and its four single-locus variants, which has only been identified in Colombian isolates. The clonal population structure demonstrates that the isolates in this study mainly belong to four clonal complexes: ST-11 cc, ST-32 cc, ST-35 cc and ST-41/44 cc. Thirty-eight penA alleles were identified, but no correlation between MICs and specific sequences was observed. CONCLUSION: This study shows that most meningococcal isolates recovered from patients with invasive meningococcal disease in Colombia are strains associated with distinct globally disseminated hyperinvasive clones.

[Molecular characterization of non-vaccine Streptococcus pneumoniae serotypes 11A, 15 B/C and 23A recovered from invasive isolates in Colombia].

INTRODUCTION: A total of 192 invasive Streptococcus pneumoniae isolates, from serotypes 11A, 15B/C and 23A (not included in the conjugated vaccines), were collected in Colombia between 1994 and 2014 as part of the activities of the Network surveillance system for the causative agents of pneumonia and meningitis (SIREVA II). OBJECTIVE: To determine the molecular characteristics of invasive S. pneumoniae isolates from serotypes 11A, 15B/C and 23A in Colombia from 1994 to 2014. MATERIALS AND METHODS: The molecular characterization of the isolates was carried out through Pulse-Field Gel Electrophoresis (PFGE) and Multilocus Sequence Typing (MLST). RESULTS: Serotype 11A showed one clonal group represented by ST62. Serotype 15B/C was composed of three groups associated with Netherlands15B-37 ST199 (28.75%), ST8495 (18.75%), and SLV (Single-Locus Variant) of ST193 (21.25%). Isolates from serotype 23A were gathered in three clonal groups, with 70.21% closely related to ST42, 17.02% to Colombia23F-ST338, and 6.38% to Netherlands15B-37 ST199. CONCLUSION: Clones Colombia23F-ST338 and Netherlands15B-ST199 covered more serotypes than those previously found by other authors, including serotype 23A. These analyses reveal the importance of capsular switching in the spreading of successful clones among non-vaccine serotypes causing invasive pneumococcal disease.

Molecular characterization of non-vaccine Streptococcus pneumoniae serotypes 11A, 15 B/C and 23A recovered from invasive isolates in Colombia / Caracterización molecular de los serotipos no vacunales 11A, 15 B/C y 23A de Streptococcus pneumoniae recuperados de aislamientos invasivos en Colombia

Resumen Introduction: A total of 192 invasive Streptococcus pneumoniae isolates, from serotypes 11A, 15B/C and 23A (not included in the conjugated vaccines), were collected in Colombia between 1994 and 2014 as part of the activities of the Network surveillance system for the causative agents of pneumonia and meningitis (SIREVA II). Objective: To determine the molecular characteristics ofinvasive S. pneumoniaeisolates from serotypes 11A, 15B/C and 23A in Colombia from 1994 to 2014. Materials and methods: The molecular characterization of the isolates was carried out through Pulse-Field Gel Electrophoresis (PFGE) and Multilocus Sequence Typing (MLST). Results: Serotype 11A showed one clonal group represented by ST62. Serotype 15B/C was composed of three groups associated with Netherlands15B-37 ST199 (28.75%), ST8495 (18.75%), and SLV (Single-Locus Variant) of ST193 (21.25%). Isolates from serotype 23A were gathered in three clonal groups, with70.21% closely related toST42, 17.02% to Colombia23F-ST338, and6.38% to Netherlands15B-37 ST199. Conclusion: Clones Colombia23F-ST338 andNetherlands15B-ST199 covered more serotypes than those previously found by other authors, including serotype 23A. These analyses reveal the importance of capsular switching in the spreading of successful clones among non-vaccine serotypes causing invasive pneumococcal disease.

Abstract Introducción. En Colombia se recolectaron 192 aislamientos invasivos de Streptococcus pneumoniae de los serotipos 11A, 15B/C y 23A (no incluidos en las vacunas conjugadas) entre 1994 y 2014, como parte de las actividades del Sistema de Redes de Vigilancia de los Agentes Responsables de Neumonías y MeningitisBacterianas (SIREVA II). Objetivo. Determinar las características moleculares de aislamientosinvasivos de los serotipos11A, 15B/C y 23A de S. pneumoniae recolectados en Colombia entre 1994 y 2014. Materiales y métodos. La caracterización molecular de los aislamientos se hizo medianteelectroforesis en gel de campo pulsado (Pulse-Field Gel Electrophoresis, PFGE) y por tipificación de secuencias multilocus (Multilocus Sequence Typing, MLST). Resultados. El serotipo 11A mostró un grupo clonal representadopor el ST62, en tanto que el serotipo15B/C se distribuyó en tres grupos asociados conlos clones Netherlands15B-37 ST199 (28,75 %), ST8495 (18,75 %) y SLV (variante en un solo locus) de ST193 (21,25 %). Los aislamientos con serotipo 23A se agruparon en tres gruposclonales; 70,21 % de ellos estaban estrechamente relacionadoscon elST42, 17,02 % con elColombia23F-ST338, y 6,38 % con el Netherlands15B-37 ST199. Conclusión. Los clones Colombia23F-ST338 y Netherlands15B-ST199 encontrados en este estudio abarcaronmás serotipos de los reportados previamente por otros autores, incluido el serotipo23A. Estos análisis revelan laimportancia de la conmutación(switching) capsular en la expansión de clones exitosos entre los serotipos no vacunales como causa de enfermedad invasiva neumocócica.

Frequency and molecular characterization of invasive isolates of Streptococcus pneumoniae serotypes 6C and 6D in Colombia / Frecuencia y caracterización molecular de aislamientos invasivos de Streptococcus pneumoniae serotipos 6C y 6D en Colombia

INTRODUCTION: Serogroup 6 of Streptococcus pneumoniae initially consisted of the 6A and 6B serotypes, but in recent years, the 6C and 6D serotypes were reported. The aim of this study was to determine the frequency and molecular characterization of invasive S. pneumoniae isolates serotypes 6C and 6D in Colombia, from 1994 to 2013. METHODOLOGY: All the isolates recovered during the surveillance from 1994 to 2013, and identified as 6A or 6B, were re-tested to detect the serotypes 6C and 6D. The serotyping was performed using the Quellung reaction and PCR. The susceptibility testing was performed on penicillin, erythromycin, ceftriaxone, trimethoprim/sulfamethoxazole, chloramphenicol, tetracycline and vancomycin. Molecular typing was performed using pulsed-field gel electrophoresis and multilocus sequence typing. RESULTS: From a total of 271 and 350 isolates serotyped previously as serotypes 6A and 6B, 61 (22.5%) and 15 (4.3%) were recognized as 6C and 6D, respectively. Isolates presented with low resistance to antimicrobials. Serotype 6C isolates were mainly associated with ST9007 (42.6%) and ST9008 (19.7%), and serotype 6D isolates with ST1135 (80%). CONCLUSION: This study showed the circulation of serotype 6C and 6D in Colombia between 1994 and 2013, information that is important to determine the dynamics of these recently described serotypes

INTRODUCCIÓN: El serogrupo 6 de Streptococcus pneumoniae estaba conformado inicialmente por los serotipos 6A y 6B, pero en los últimos años los serotipos adicionales 6C y 6D fueron reportados. El objetivo de este estudio fue determinar la frecuencia y la caracterización molecular de aislamientos invasivos de S.pneumoniae serotipos 6C y 6D en Colombia, desde 1994 a 2013. METODOLOGÍA: Todos los aislamientos recuperados durante la vigilancia 1994-2013 e identificados como 6A o 6B se analizaron para detectar los serotipos 6C y 6D. La serotipificación se realizó usando la reacción de Quellung y PCR. La prueba de sensibilidad se realizó a la penicilina, eritromicina, ceftriaxona, trimetoprim/sulfametoxazol, cloranfenicol, tetraciclina y vancomicina. La tipificación molecular se realizó mediante electroforesis en gel de campos pulsados y análisis de las secuencias multilocus. RESULTADOS: De un total de 271 y 350 aislamientos previamente identificados como serotipos 6A y 6B, 61 (22,5%) y 15 (4,3%) fueron reconocidos como 6C y 6D, respectivamente. Los aislamientos presentaron una baja resistencia a los antimicrobianos. Los aislamientos serotipo 6C se asociaron principalmente a los ST9007 (42,6%) y ST9008 (19,7%). El 80% de los aislamientos 6D se asociaron con ST 1135. CONCLUSIÓN: Este estudio demostró la circulación del serotipo 6C y 6D en Colombia desde 1994. La información es importante para determinar la dinámica de estos serotipos descritos recientemente

Frequency and molecular characterization of invasive isolates of Streptococcus pneumoniae serotypes 6C and 6D in Colombia.

INTRODUCTION: Serogroup 6 of Streptococcus pneumoniae initially consisted of the 6A and 6B serotypes, but in recent years, the 6C and 6D serotypes were reported. The aim of this study was to determine the frequency and molecular characterization of invasive S. pneumoniae isolates serotypes 6C and 6D in Colombia, from 1994 to 2013. METHODOLOGY: All the isolates recovered during the surveillance from 1994 to 2013, and identified as 6A or 6B, were re-tested to detect the serotypes 6C and 6D. The serotyping was performed using the Quellung reaction and PCR. The susceptibility testing was performed on penicillin, erythromycin, ceftriaxone, trimethoprim/sulfamethoxazole, chloramphenicol, tetracycline and vancomycin. Molecular typing was performed using pulsed-field gel electrophoresis and multilocus sequence typing. RESULTS: From a total of 271 and 350 isolates serotyped previously as serotypes 6A and 6B, 61 (22.5%) and 15 (4.3%) were recognized as 6C and 6D, respectively. Isolates presented with low resistance to antimicrobials. Serotype 6C isolates were mainly associated with ST9007 (42.6%) and ST9008 (19.7%), and serotype 6D isolates with ST1135 (80%). CONCLUSION: This study showed the circulation of serotype 6C and 6D in Colombia between 1994 and 2013, information that is important to determine the dynamics of these recently described serotypes.

Characterization of Carriage Isolates of Neisseria meningitides in the Adolescents and Young Adults Population of Bogota (Colombia).

BACKGROUND: Meningococcal carriage studies are important to improve our understanding of the epidemiology of meningococcal disease. The aim of this study was to determine the prevalence of meningococcal carriage and the phenotypic and genotypic characteristics of isolates collected from a sample of students in the city of Bogotá, Colombia. MATERIALS AND METHODS: A total of 1459 oropharyngeal samples were collected from students aged 15-21 years attending secondary schools and universities. Swabs were plated on a Thayer Martin agar and N. meningitidis was identified by standard microbiology methods and PCR. RESULTS: The overall carriage prevalence was 6.85%. Carriage was associated with cohabitation with smokers, and oral sex practices. Non-groupable and serogroup Y isolates were the most common capsule types found. Isolates presented a high genetic diversity, and circulation of the hypervirulent clonal complexes ST-23, ST-32 and ST-41/44 were detected. CONCLUSION: The meningococcal carriage rate was lower than those reported in Europe and Africa, but higher than in other Latin American countries. Our data also revealed antigenic and genetic diversity of the isolates and the circulation of strains belonging to clonal complexes commonly associated with meningococcal disease.

Phenotypic and genotypic characterization of Neisseria meningitidis serogroup B isolates from Cartagena, Colombia, 2012-2014.

INTRODUCTION: Neisseria meningitidis is one of the leading causes of bacterial meningitis. In 2013, an increase in invasive disease caused by N. meningitidis serogroup B occurred in Cartagena, Colombia. OBJECTIVE: The aim of this study was to characterize serogroup B isolates recovered from patients with meningococcal meningitis in Cartagena during 2012 and 2014. MATERIALS AND METHODS: Twenty-five isolates were collected through a national, laboratory-based surveillance, and phenotypic and genotypic characteristics were determined by serosubtyping, serotyping, antimicrobial susceptibility testing, repetitive sequence-based PCR (rep-PCR). MLST data available were also used. RESULTS: The B:10,15:nt phenotype, associated with clonal complex ST-41/44, was responsible for 68.0% of all cases. CONCLUSION: The clinical, epidemiological and molecular characterization of meningococcal disease is necessary for understanding the spread of virulent meningococcal clones and for facilitating the early detection of cases to reduce epidemic risks.

Serotype and genotype distribution among invasive Streptococcus pneumoniae isolates in Colombia, 2005-2010.

In Colombia, a laboratory-based surveillance of invasive Streptococcus pneumoniae isolates as part of SIREVA II PAHO has been conducted since 1994. This study describes the serotype distribution, antimicrobial resistance, and genetic relationships of pneumococcal isolates recovered in Colombia from 2005 to 2010. In this study, demographic data of invasive S. pneumoniae isolates were analyzed, and antimicrobial susceptibility patterns were determined. Pulse field gel electrophoresis (n = 629) and multilocus sequence typing (n = 10) were used to determine genetic relationship of isolates with minimal inhibitory concentration to penicillin ≥0.125 µg/mL. A total of 1775 isolates of S. pneumoniae were obtained. Fifteen serotypes accounted for 80.7% of isolates. Serotype 14 (23.1%) was the most frequent in the general population. Penicillin resistance was 30.7% in meningitis and 9.0% in non-meningitis. Clones Spain(6B)ST90, Spain(9V)ST156, Spain(23F)ST81, and Colombia(23F)ST338 were associated to isolates. Additionally, serotype 6A isolates were associated with ST460 and ST473, and 19A isolates with ST276, ST320, and ST1118. In conclusion, the surveillance program provided updated information of trends in serotype distribution, antimicrobial resistance and the circulation of clones in invasive pneumococcal diseases. These results could be helpful to understand the epidemiology of S. pneumoniae in Colombia, and provide a baseline to measure the impact of vaccine introduction.

Molecular characterization of Streptococcus pneumoniae serotype 1 invasive isolates in Colombia.

OBJECTIVE: To determine the genetic relationship between Streptococcus pneumoniae serotype 1 Colombian isolates recovered from invasive disease between 1994 and 2011 and recognized serotype 1 international clones. METHODS: A total of 135 S. pneumoniae serotype 1 isolates with epidemiological and antimicrobial susceptibility data (Clinical and Laboratory Standards Institute, 2012) were studied. The genetic relationship with recognized international clones was established by pulsed-field gel electrophoresis (PFGE) with SmaI restriction enzyme. Multilocus sequence typing (MLST) was standardized to determine the sequence type (ST) in seven isolates representing different clonal groups. Control and reference strain R6, and clones Sweden¹ ST217, Sweden¹ ST304, Sweden¹ ST306, and USA¹ ST615, were used. RESULTS: PFGE revealed that 89.7% of the isolates were associated with Sweden¹ ST306, 3.7% were associated with Sweden¹ ST304, and 6.6% were not clonally related. Using MLST, ST306 was confirmed in six isolates and ST304 in one. CONCLUSIONS: In contrast to Brazil and the United States, where clones Sweden¹ ST304 and ST227 prevail, invasive disease caused by S. pneumoniae serotype 1 in Colombia is principally associated with the dispersion of isolates related to clone Sweden¹ ST306.

Molecular characterization of Streptococcus pneumoniae serotype 1 invasive isolates in Colombia / Caracterización molecular de cepas invasoras de Streptococcus pneumoniae serotipo 1 aisladas en Colombia

OBJECTIVE: To determine the genetic relationship between Streptococcus pneumoniae serotype 1 Colombian isolates recovered from invasive disease between 1994 and 2011 and recognized serotype 1 international clones. METHODS: A total of 135 S. pneumoniae serotype 1 isolates with epidemiological and antimicrobial susceptibility data (Clinical and Laboratory Standards Institute, 2012) were studied. The genetic relationship with recognized international clones was established by pulsed-field gel electrophoresis (PFGE) with SmaI restriction enzyme. Multilocus sequence typing (MLST) was standardized to determine the sequence type (ST) in seven isolates representing different clonal groups. Control and reference strain R6, and clones Sweden¹ ST217, Sweden¹ ST304, Sweden¹ ST306, and USA¹ ST615, were used. RESULTS: PFGE revealed that 89.7% of the isolates were associated with Sweden¹ ST306, 3.7% were associated with Sweden¹ ST304, and 6.6% were not clonally related. Using MLST, ST306 was confirmed in six isolates and ST304 in one. CONCLUSIONS: In contrast to Brazil and the United States, where clones Sweden¹ ST304 and ST227 prevail, invasive disease caused by S. pneumoniae serotype 1 in Colombia is principally associated with the dispersion of isolates related to clone Sweden¹ ST306.

OBJETIVO: Determinar la relación genética entre las cepas de Streptococcus pneumoniae serotipo 1 aisladas en Colombia en casos de enfermedad invasora entre 1994 y 2011 y los clones internacionales reconocidos del serotipo 1. MÉTODOS: Se estudiaron un total de 135 cepas de S. pneumoniae serotipo 1 de las que se tenían datos epidemiológicos y de sensibilidad a los antimicrobianos (Clinical and Laboratory Standards Institute, 2012). Se estableció su relación genética con los clones internacionales reconocidos mediante electroforesis en gel de campo pulsátil (PFGE) utilizando la enzima de restricción SmaI. Se estandarizó la tipificación de secuencias mulitlocus (MLST) para determinar el tipo de secuencia (ST) en siete cepas que representaban diferentes grupos clonales. Se utilizaron la cepa de control y referencia R6 y los clones Sweden¹ ST217, Sweden¹ ST304, Sweden¹ ST306, y USA¹ ST615. RESULTADOS: La PFGE reveló que 89,7% de las cepas se asociaban con Sweden¹ ST306, 3,7% con Sweden¹ ST304, y 6,6% no mostraron relación clonal. Mediante MLST, se confirmó la relación con ST306 en seis cepas y con ST304 en una. CONCLUSIONES: A diferencia de Brasil y Estados Unidos, donde prevalecen los clones Sweden¹ ST304 y ST227, la enfermedad invasora causada por S. pneumoniae serotipo 1 en Colombia se asocia principalmente con la dispersión de cepas relacionadas con el clon Sweden¹ ST306.

Changes in Streptococcus pneumoniae serotype distribution in invasive disease and nasopharyngeal carriage after the heptavalent pneumococcal conjugate vaccine introduction in Bogotá, Colombia.

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.