Primer reporte de un brote de dengue en balsas, Amazonas, Perú, durante 2021 y 2022

Introducción: El aumento de casos de dengue en Amazonas es un riesgo para la salud pública. En el 2021, Balsas reportó por primera vez un brote de dengue. Métodos: La población incluyó a pacientes que cumplían con la definición de caso entre diciembre 2021 y febrero 2022. La identificación de los serotipos se determinó mediante una qRT-PCR múltiplex. Resultados: Se identificaron 72 pacientes de los cuales 53 (74%) se confirmaron por serología (Ag NS1). El serotipo prevalente fue DENV-2 (94%), y el 6% fue DENV-1. Los pacientes de 19 a 45 años presentaron el mayor porcentaje de casos (59%). Los síntomas más frecuentes fueron cefalea, mialgias, fiebre y artralgias; el 23 % presentó dolor abdominal intenso. Conclusión: Este fue el primer brote de dengue confirmado en el distrito de Balsas, siendo DENV-2 el principal causante, destacando la necesidad de mejorar la vigilancia en zonas sin transmisión autóctona de la enfermedad.

Introduction: The increase in dengue cases in Amazonas represents a public health risk. In 2021, Balsas reported a dengue outbreak for the first time. Methods: The population included patients who met the case definition between December 2021 and February 2022. Serotype identification was determined using a multiplex qRT-PCR. Results: A total of 72 patients were identified, of which 53 (74%) were confirmed by serology (NS1 Ag). The prevalent serotype was DENV-2 (94%), and 6% were DENV-1. Patients aged 19 to 45 years had the highest percentage of cases (59%). The most frequent symptoms were headache, myalgia, fever, and arthralgia; 23% had intense abdominal pain. Conclusion: This was the first confirmed dengue outbreak in the Balsas district, with DENV-2 being the main cause of the outbreak, highlighting the need to improve surveillance in areas without autochthonous transmission of the disease.

Vigilancia virológica de casos de Dengue de enero 2020 a febrero 2023, en el Departamento de La Paz-Bolivia / Virological surveillance of Dengue cases since January 2020 to February 2023 La Paz-Bolivia

Introducción: El dengue se ha convertido en un problema serio de salud pública en Bolivia. Por la capacidad de infección del virus del dengue, el diagnóstico es amplio y varia con la evolución de la enfermedad. El incremento de la temperatura y las lluvias de la época son los factores ambientales principales para la reproducción del mosquito transmisor (Aedes aegypti), y el aumento de casos de dengue. Objetivos: Realizar un estudio transversal-retrospectivo de los casos de dengue en el departamento de La Paz - Bolivia, durante el periodo de enero de 2020 hasta febrero de 2023. Materiales y Métodos: De las bases obtenidas del Laboratorio de Virología- INLASA, se analizaron variables como el número de casos positivos de cada gestión, la distribución de los casos positivos según el lugar probable de infección tanto por departamento como por provincia, la variación temporal de los casos y el serotipo prevalente por gestión, y la distribución de casos positivos por género y grupo etario, en este trabajo se realizó un estudio transversal-retrospectivo. Resultados: Durante las cuatro gestiones analizadas el número total de casos notificados fue de 2143, detectando 1184 (55.2%) positivos. Señalando como lugar probable de infección en gran parte la provincia de Sud Yungas. Con respecto a la variación temporal presentó un mismo comportamiento en tres gestiones. Prevaleció en tres gestiones el serotipo DENV 1 sobre DENV 2, observando un aumento de serotipo DENV 2 hasta febrero del 2023. Además, el grupo atareo más afectado con dengue oscila entre los 10 a 39 años, no encontrando diferencia significativa entre género masculino y femenino. Conclusiones: Este estudio revela que el dengue es un problema de salud pública no solo del oriente del país sino también de las zonas tropicales del departamento de La Paz. Es necesario el diagnóstico rápido y efectivo; realizar la tipificación del virus y el llenado correcto de fichas epidemiológicas para un mejor control virológico.

Background: Dengue has become a serious problem in public health in Bolivia. Due the infection capacity of dengue virus, the diagnosis is broad and varies with the evolution of the disease. The increase of temperature and rain season are the main environmental factors of reproduction in the transmitting mosquito (Aedes aegipty), and the increase in dengue cases. Objectives: To carry out a retrospective crossover study of dengue cases in La Paz Department - Bolivia, during the period from January 2020 to February 2023. Materials and Methods: From databases obtained from INLASA Virology Laboratory during periods 2020, 2021, 2022 and the beginnings of 2023, variables such as number of positive cases from each year, distribution of positive cases according to the probable place of infection were obtained and analyzed, by department and by province; the temporal variation of the cases and the prevalent serotype by period, and finally distribution of positive cases by sex group and age group. Its make a retrospective crossover study. Results: During the four analyzed periods, within the total number of 2143 reported cases, there were 1184 (55.2%) of positive cases for Dengue. On the other hand, the department of La Paz (86.3%) is indicated as the probable place of infection, with Sud Yungas province (municipalities La Asunta and Palos Blancos) being the places with the most positive cases. The temporal variation in suspected and confirmed cases has presented the same behavior in three years. DENV 1 serotype predominated over DENV 2 in three years, observing an increase in DENV 2 serotype until February 2023. In addition, the age group most affected by dengue ranges from 10 to 39 years, finding no significant difference between masculine and feminine gender. Discussions: An increase in cases between months of February and April, coinciding with rain season in Bolivia. Due to the climate in the tropical areas of the department, there is a greater number of positive cases in those areas. Conclusions: This study reveals that Dengue is a public health problem not only in eastern part of the country but also in tropical areas of La Paz department. A quick and effective diagnosis is necessary; to carry out the typing of the virus and the correct filling out of epidemiological files for better virological control.

Prueba de microneutralización para la detección de anticuerpos contra el virus dengue serotipo 2

Objetivo: Optimizar la prueba de microneutralización (MNT) para detección de anticuerpos neutralizantes contra el virus dengue serotipo 2 (DENV-2) en la línea celular Vero-76. Materiales y métodos: Se evaluaron diferentes concentraciones celulares (0.6 x105 cel/mL, 0.9 x105 cel/mL, 1.2 x105 cel/mL), porcentajes de 2 %, 3 % y 4 % de suero bovino fetal (SBF), número de pasajes del stock de virus y los días de incubación. La semilla viral se confirmó por RT-qPCR. El DENV-2 se propagó realizando 5 pasajes en células Vero-76, seguidamente se tituló el virus en placas de 96 pozos y se evaluaron 2 métodos de infección celular: monocapa y células en suspensión, además se determinó el día óptimo de coloración de las células. Obtenidos los resultados, se procesaron mediante MNT para DENV-2 las siguientes muestras: 5 sueros negativos a DENV-2 y YFV (Virus de la Fiebre Amarilla), 5 sueros negativos de anticuerpos a DENV-2 y positivos de anticuerpos a YFV y 5 sueros positivos de anticuerpos a DENV-2 seleccionados mediante la prueba de neutralización por reducción de placas (PRNT). Resultados: El método óptimo para MNT utilizó células en suspensión (0.9 x 105 cel/mL), 2 % de SBF y semilla viral pasaje 5. La mínima dilución capaz de diferenciar una muestra positiva a DENV-2 fue 1:40 y el tiempo de incubación para la MNT para DENV-2 fue de 10 días. Conclusión: La MNT con el método de células en suspensión y medio de cultivo con 2 % de SBF permite detectar anticuerpos neutralizantes IgG contra DENV-2 con resultados confiables, pudiendo analizar un mayor número de muestras con ahorro de materiales.

Objective: To optimize the microneutralization test (MNT) for the detection of neutralizing antibodies against serotype 2 of dengue fever virus (DENV-2) in a Vero-76 cell line. Materials and methods: Different cell concentrations were assessed (0.6 X 105 cells/mL, 0.9 X 105 cells/mL, and 1.2 x 105 cells/mL) with 2%, 3%, and 4% fetal bovine serum, virus stock passage number, and incubation days. Viral particles were confirmed using RT-qPCR. DENV-2 disseminated with 5 passages in Vero-76 cells, then, the virus was titrated in 96-well plaques, and two methods for cell infection were evaluated: single layer, and suspended cells. Also, the optimum day for cell staining was determined. Once results were obtained, the following samples were processed using MNT for DENV-2: five sera negative for DENV-2 and yellow fever virus (YFV), five sera negative for antibodies against DENV-2 and positive for antibodies against YFV, and five sera positive for antibodies against DENV-2 that were selected using the plate reduction neutralization test. Results: The optimum method for MNT used suspended cells (0.9 X 105 cells/mL), 2% fetal bovine serum, and viral particles at the 5th passage. The minimal dilution able to differentiate a positive sample for DENV2 was 1:40, and the MNT incubation time for DENV-2 was ten days. Conclusion: MNT with the cell suspension method and a culture medium with 2% fetal bovine serum allows the detection of IgG neutralizing antibodies against DENV-2 with reliable results, so that larger sample sizes may be assessed, saving materials to be used.

Serotipos y resistencia antimicrobiana de Streptococcus pneumoniae en población pediátrica china: una revisión de alcance

Esta revisión tuvo como propósito explorar la distribución de serotipos y la resistencia antimicrobiana de Streptococcus pneumoniae en la población pediátrica de China a partir de literatura publicada en los últimos seis años. Se realizó una revisión de alcance a partir de PubMed y dos bases de datos de China: CNKI y WanFang Data. Del total de 196 artículos extraídos, se seleccionaron 14 estudios para esta revisión. Hay 13 artículos que analizan la distribución de serotipos de Streptococcus pneumoniae; los serotipos más frecuentemente registrados son: 19F, 19A, 23F, 14 y 6B. Hay 11 artículos que analizan la resistencia antimicrobiana de Streptococcus pneumoniae, la prevalencia de no susceptibles a la penicilina se encuentra en el rango de 0 % a 95,7 %. Los aislados son muy resistentes a eritromicina, clindamicina, tetraciclina y trimetoprima-sulfametoxazol; son resistentes a penicilina en meningitis neumocócica pero son sensibles a penicilina en otras enfermedades neumocócicas, además, son muy sensibles a levofloxacina, vancomicina y Linezolid. Se concluye que la vacuna antineumocócica conjugada 13 tiene alta cobertura en los serotipos de Streptococcus pneumoniae en los niños de China continental, por eso se recomienda su inclusión en el programa de vacunación infantil; al mismo tiempo, se debe tener en cuenta la aparición de la sustitución de serotipos. Por eso, se deben incluir más pacientes pediátricos o niños en las investigaciones, especialmente los menores de cinco años. Es necesaria una vigilancia de alta calidad a largo plazo sobre la distribución de serotipos y resistencia antimicrobiana de Streptococcus pneumoniae para el desarrollo de la prevención de enfermedades neumocócicas.

This review aimed to explore the serotype distribution and antimicrobial resistance of Streptococcus pneumoniae in the Chinese pediatric population based on literature published in the last six years. A scoping review was performed using PubMed and two Chinese databases: CNKI and WanFang Data. Of the total of 196 articles extracted, 14 studies were selected for this review. There are 13 articles that analyze the distribution of Streptococcus pneumoniae serotypes, the most frequently registered serotypes are: 19F, 19A, 23F, 14 and 6B. There are 11 articles that analyze the antimicrobial resistance of Streptococcus pneumoniae, the prevalence of non-susceptible to penicillin is in the range of 0% to 95.7%. Isolates are highly resistant to erythromycin, clindamycin, tetracycline, and trimethoprim-sulfamethoxazole; they are resistant to penicillin in pneumococcal meningitis but are sensitive to penicillin in other pneumococcal diseases, in addition, they are very sensitive to levofloxacin, vancomycin and Linezolid. It is concluded that the pneumococcal conjugate vaccine 13 has high coverage in Streptococcus pneumoniae serotypes in children from mainland China, therefore its inclusion in the childhood vaccination program is recommended; at the same time, the occurrence of serotype substitution should be taken into account. Therefore, more pediatric patients or children should be included in research, especially those under five years of age. Long-term, high-quality surveillance of the serotype distribution and antimicrobial resistance of Streptococcus pneumoniae is necessary for the development of pneumococcal disease prevention.

Caracterización de estreptococos beta-hemolíticos del grupo A con fenotipo mucoide aislados en un hospital de tercer nivel / Characterization of group A beta-haemolytic streptococcus with mucoid phenotype isolated in a tertiary hospital

Introducción: El objetivo de este estudio es la caracterización de cepas de Streptococcus pyogenes con fenotipo mucoide y su comparación con las cepas no mucoides aisladas entre abril y agosto de 2016. Material y métodos: Se llevó a cabo la caracterización y el estudio de sensibilidad antimicrobiana de todos los aislados. Se determinó el tipo emm y se analizaron los genes de exotoxinas speA, speB, speC, speF, speG, speH, speJ, speZ y ssa. Se recogieron datos clínicos y demográficos. Resultados: De 96 aislados analizados, el 47% presentaron un fenotipo mucoide, y de estos últimos, el 95,5% presentaron los genes speA-speB-speF-speG-ssa y genotipo emm3. La principal manifestación clínica entre todos los pacientes fue faringoamigdalitis (77,1%) que evolucionó a escarlatina en el 67,5% de los casos. Conclusión: Se describe la circulación de una cepa de aspecto mucoide con perfil de toxinas speA-speB-speF-speG-ssa y genotipo emm3.1 considerado de los más frecuentes y más virulentos de SGA.(AU)

Introduction: The objective of this study is to characterize Streptococcus pyogenes isolates with a mucoid phenotype and to compare them with non-mucoid isolates obtained between April and August 2016. Material and methods: Identification and antimicrobial susceptibility were performed in all isolates. The emm type and exotoxin genes speA, speB, speC, speF, speG, speH, speJ, speZ and ssa were analyzed. Clinical and demographic data were collected. Results: From 96 isolates analyzed, 47% had a mucoid phenotype and 95.5% of them presented speA-speB-speF-speG-ssa genes and emm3 genotype. The main clinical manifestation was pharyngotonsillitis (77.1%) evolving to scarlet fever in 67.5% of the cases. Conclusion: This study describes the circulation of a mucoid phenotype strain with a speA-speB-speF-speG-ssa toxin profile and emm3.1 genotype considered one of the most frequent and virulent of SGA.(AU)

Characterization of group A beta-haemolytic streptococcus with mucoid phenotype isolated in a tertiary hospital.

INTRODUCTION: The objective of this study is to characterize Streptococcus pyogenes isolates with a mucoid phenotype and to compare them with non-mucoid isolates obtained between April and August 2016. MATERIAL AND METHODS: Identification and antimicrobial susceptibility were performed in all isolates. The emm type and exotoxin genes speA, speB, speC, speF, speG, speH, speJ, speZ and ssa were analyzed. Clinical and demographic data were collected. RESULTS: From 96 isolates analyzed, 47% had a mucoid phenotype and 95.5% of them presented speA-speB-speF-speG-ssa genes and emm3 genotype. The main clinical manifestation was pharyngotonsillitis (77.1%) evolving to scarlet fever in 67.5% of the cases. CONCLUSION: This study describes the circulation of a mucoid phenotype strain with a speA-speB-speF-speG-ssa toxin profile and emm3.1 genotype considered one of the most frequent and virulent of SGA.

Antibacterial activity of Citrus hystrix toward Salmonella spp. infection.

INTRODUCTION: Citrus hystrix is widely used by Indonesians as a traditional medicine for gastrointestinal diseases, including Salmonella spp. infection. We investigated the antibacterial activity of the ethanolic peel extract of C. hystrix against Salmonella typhimurium. METHODS: The antibacterial activity was evaluated both in vitro and in vivo. The minimum inhibitory concentration (MIC) of the extract was determined at a concentration of 0.625% by agar dilution assay. Later, the in vivo antibacterial activity was examined by the administration of 16mg of the extract daily for three consecutive days in a mouse model infected with S. typhimurium. RESULTS: The bacterial loads of S. typhimurium in the ileum, liver, and spleen decreased after 24h of administration of the extract (p=0.00008, p=0.00084, and p=0.00003, respectively). CONCLUSION: The ethanolic peel extract of C. hystrix shows antibacterial activity against S. typhimurium, indicating the potential of C. hystrix as an effective treatment for Salmonella spp. infection.

Antibacterial activity of Citrus hystrix toward Salmonella spp. infection / Actividad antibacteriana de Citrus hystrix frente a la infección por Salmonella spp

Introduction: Citrus hystrix is widely used by Indonesians as a traditional medicine for gastrointestinal diseases, including Salmonella spp. infection. We investigated the antibacterial activity of the ethanolic peel extract of C. hystrix against Salmonella typhimurium. Methods: The antibacterial activity was evaluated both in vitro and in vivo. The minimum inhibitory concentration (MIC) of the extract was determined at a concentration of 0.625% by agar dilution assay. Later, the in vivo antibacterial activity was examined by the administration of 16mg of the extract daily for three consecutive days in a mouse model infected with S. typhimurium. Results: The bacterial loads of S. typhimurium in the ileum, liver, and spleen decreased after 24h of administration of the extract (p=0.00008, p=0.00084, and p=0.00003, respectively). Conclusion: The ethanolic peel extract of C. hystrix shows antibacterial activity against S. typhimurium, indicating the potential of C. hystrix as an effective treatment for Salmonella spp. infection.(AU)

Introducción: El Citrus hystrix es muy utilizado por los indonesios como medicina tradicional para las enfermedades gastrointestinales, incluida la infección por Salmonella spp. Investigamos la actividad antibacteriana del extracto etanólico de piel de C. hystrix frente a Salmonella typhimurium. Métodos: La actividad antibacteriana se evaluó tanto in vitro como in vivo. La concentración mínima inhibitoria (CMI) del extracto se determinó a una concentración del 0,625% mediante un ensayo de dilución en agar. Posteriormente, se evaluó la actividad antibacteriana in vivo mediante la administración de 16mg de extracto de forma diaria durante 3 días consecutivos en un modelo murino infectado con S. typhimurium. Resultados: La carga bacteriana de S. typhimurium en el íleo, el hígado y el bazo se redujo 24h después de la administración del extracto (p=0,00008, p=0,00084 y p=0,00003, respectivamente). Conclusión: El extracto etanólico de piel de C. hystrix muestra actividad antibacteriana frente a S. typhimurium, lo que indica el potencial de C. hystrix como tratamiento eficaz para la infección por Salmonella spp.(AU)

Characterization of group A beta-haemolytic streptococcus with mucoid phenotype isolated in a tertiary hospital. / Caracterización de estreptococos beta-hemolíticos del grupo A con fenotipo mucoide aislados en un hospital de tercer nivel.

INTRODUCTION: The objective of this study is to characterize Streptococcus pyogenes isolates with a mucoid phenotype and to compare them with non-mucoid isolates obtained between April and August 2016. MATERIAL AND METHODS: Identification and antimicrobial susceptibility were performed in all isolates. The emm type and exotoxin genes speA, speB, speC, speF, speG, speH, speJ, speZ and ssa were analyzed. Clinical and demographic data were collected. RESULTS: From 96 isolates analyzed, 47% had a mucoid phenotype and 95.5% of them presented speA-speB-speF-speG-ssa genes and emm3 genotype. The main clinical manifestation was pharyngotonsillitis (77.1%) evolving to scarlet fever in 67.5% of the cases. CONCLUSION: This study describes the circulation of a mucoid phenotype strain with a speA-speB-speF-speG-ssa toxin profile and emm3.1 genotype considered one of the most frequent and virulent of SGA.

Enfermedad invasiva asociada a neumococo y síndrome urémico hemolítico, nuevo serotipo / Invasive pneumococcal disease and hemolytic uremic syndrome: new serotype

El síndrome urémico hemolítico asociado a Streptococcus pneumoniae (SUH-Sp) se define como anemia hemolítica microangiopática, plaquetopenia y lesión renal aguda, en un paciente con infección invasiva por Streptococcus pneumoniae (Sp). Varón de 2 años, con neumonía con derrame pleural por Sp aislado en hemocultivos y líquido pleural. A las 72 h, presentó palidez, decaimiento, quejido respiratorio y oliguria. En el análisis de laboratorio se encontró anemia, plaquetopenia, aumento de la urea, la creatinina y la lactato deshidrogenasa en sangre; coombs directa +; esquistocitos en frotis; fibrinógeno; coagulograma normal; dímero D aumentado. Orina con proteinuria y hematuria. En Terapia Intensiva requirió asistencia respiratoria mecánica y transfusión con glóbulos rojos lavados; se recuperó progresivamente. El Instituto Malbrán informó serotipo 38 de Sp. Es el primer paciente comunicado con este serotipo

Streptococcus pneumoniae associated hemolytic uremic syndrome (Sp-HUS) is defined as microangiopathic hemolytic anemia, thrombocytopenia and acute renal injury, in a patient with Streptococcus pneumoniae (Sp) invasive infection. A 2-year-old boy was admitted with pneumonia and empyema. Sp was isolated from blood and pleural fluid cultures. After 72 h, the patient showed paleness, asthenia, respiratory whining and oliguria. Laboratory showed anemia, low platelets, increased blood urea, creatirnina, lactate dehdrogenase, direct Coombs +, schistocytes, fibrinogen, normal coagulogram and increased D-dimer. Proteinuria and hematuria were detected in urine. Mechanical ventilatory assistance and transfusions of washed red blood cells were required. The patient recovered progressively. Sp serotype 38 was isolated in the National Reference Laboratory "Malbran". This is the first report associated to this serotype

Increase of serotype 8, ST53 clone, as the prevalent strain of Streptococcus pneumoniae causing invasive disease in Madrid, Spain (2012-2015).

INTRODUCTION: In recent years, Streptococcus pneumoniae serotype 8 has become the most prevalent cause of invasive pneumococcal disease (IPD) in Madrid, Spain. The objective of this study was to characterize the invasive clones of S. pneumoniae serotype 8 in Madrid over the 2012-2015 period. METHODS: From January 2012 to December 2015, a total of 1543 invasive isolates were studied. Serotyping was carried out by Pneumotest-Latex agglutination and Quellung reaction. Susceptibilities to penicillin, erythromycin and levofloxacin were determined by the Etest®. All serotype 8 strains were typed by multilocus sequence typing (MLST) and by pulsed-field gel electrophoresis (PFGE). RESULTS: Two hundred and forty-eight (248) serotype 8 strains were detected (16.1%) and 243 of them were available for molecular typing. Nine sequence types (STs) by MLST (8-ST53, 8-ST63, 8-ST404, 8-ST1107, 8-ST989, 8-ST1110, 8-ST2231, 8-ST3544 and 8-ST4301), and nine PFGE profiles were identified (one corresponding to each ST). The 8-ST53 clone was the most widespread, and increased from 53.8% among all serotype 8 isolates in 2012, to 90.1% in 2015. In contrast, the 8-ST63 clone, resistant to levofloxacin and erythromycin, decreased from 30.8%, among all serotype 8 strains in 2012, to 5.0% in 2015. CONCLUSIONS: The increase in our region of S. pneumoniae serotype 8, not included in conjugated vaccines, occurred at the expense of the 8-ST53 clone. On the contrary, the 8-ST63 clone decreased. Since clone 8-ST63 has the theoretical advantage of its levofloxacin-erythromycin resistance in comparison to 8-ST53, the predominance of 8-ST53 over 8-ST63 is striking.

[Invasive Streptococcus pyogenes infections (2011-2018): EMM-type and clinical presentation]. / Infecciones invasoras por Streptococcus pyogenes (2011-2018): serotipos y presentación clínica.

INTRODUCTION: Streptococcus pyogenes (S. pyogenes) is an important human pathogen that is responsible for a broad range of infections, from uncomplicated to more severe and invasive diseases with high morbidity/mortality. The M protein (emm type) is a critical virulence factor. Several studies have shown an increased incidence of invasive S. pyogenes disease. This was associated with an increase in the prevalence of M1 and M3 types, well-recognised virulent M types. The aim of the present study was to confirm the resurgence of invasive S. pyogenes disease during 2011-2018 and to identify the relationship between specific M types with disease presentation. MATERIAL AND METHODS: Isolates were confirmed using standard techniques: colony morphology, ß-haemolysis, biochemical tests, and agglutination with specific antisera (DiaMondiaL Strep Kit, DiaMondiaL, Langenhagen, Germany). The antibiotic sensitivity was performed using microdilution (Vitek®2 Compact, bioMeriéux, Inc., Durham, NC). Molecular analysis included the determination of the emm gene and superantigen profile. RESULTS: A total of 29 invasive isolates were collected (2011-2018) from blood (16), pleural fluid (9), synovial fluid (3), and cerebrospinal fluid (1). One strain per year was isolated between 2011 and 2013, with 2, 5, 4, 6, and 9 strains being isolated between 2014 and 2018, respectively. The most frequent clinical presentations were bacteraemia and pneumonia (10 and 9 cases). The predominant types were M1 (11 isolates) and M3 (3 isolates). A correlation was found between M1 and M3 types, and pneumonia (6/7 cases) and deep soft tissue infections (3/3 cases). CONCLUSIONS: An increased incidence of invasive S. pyogenes disease was observed during the study period, with M1 and M3 types being those most commonly isolated and associated with pneumonia and deep soft tissue infections.

Caracterización genética de cepas de Listeria monocytogenes aisladas durante los años 2007-2014 en Chile / Genetic characterization of Listeria monocytogenes strains isolated during 2007-2014 in Chile

Resumen Introducción: Listeria monocytogenes es un patógeno transmitido por alimentos que causa listeriosis, una enfermedad que puede presentarse como gastroenteritis febril o en una forma invasora que tiene altas tasas de mortalidad. Hasta el momento, ha sido poco estudiada la diversidad genética de cepas de L. monocytogenes aisladas desde pacientes, alimentos y fuentes ambientales en Chile. Objetivo: Caracterizar genéticamente cepas de L. monocytogenes de estos tres orígenes recibidas por el Instituto de Salud Pública de Chile (ISP) entre los años 2007 y 2014. Material y Métodos: Se seleccionaron 94 cepas de L. monocytogenes correspondientes a 94 pulsotipos diferentes identificados por electroforesis en gel de campo pulsado (PFGE), se extrajo ADN y se realizó serotipificación mediante reacción de polimerasa en cadena (RPC) y tipificación de secuencias multilocus (MLST). Resultados: El serotipo más común fue 4b (55,3%), seguido de 1/2a (25,5%), 1/2b (17%) y 1/2c (2,2%). Se identificaron 32 secuencias tipo (ST), de las cuales cuatro fueron nuevas, y las predominantes fueron ST1 (28,7%) y ST2 (13,8%). La totalidad de las cepas se agrupó en los Linajes I y II. Conclusiones: Se observó una gran variabilidad genética en las cepas de L. monocytogenes analizadas, siendo predominantes las secuencias tipo ST1 y ST2, ambas pertenecientes al Linaje I. Nuestros resultados contribuyen a conocer la estructura poblacional de este patógeno en Chile y su presencia en muestras clínicas, alimentos y el medio ambiente.

Background: Listeria monocytogenes is a foodborne pathogen that causes listeriosis, a disease that can present as febrile gastroenteritis or as an invasive form that has high mortality rates. So far, the genetic diversity of strains of L. monocytogenes isolated from patients, foods and environmental sources in Chile has been poorly studied. Aim: To characterize genetically L. monocytogenes strains received by the Institute of Public Health of Chile (ISP) between 2007 and 2014. Methods: We selected 94 strains of L. monocytogenes corresponding to 94 different pulsotypes identified by pulsed field gel electrophoresis (PFGE), DNA was extracted and serotyping was performed by polymerase chain reaction (PCR) and multilocus sequence typing (MLST). Results: The most common serotype was 4b (55.3%), followed by serotypes 1/2a (25.5%), 1/2b (17%) and 1/2c (2.2%). 32 sequence-type (ST) were identified, of which 4 were new, and the predominant ones were ST1 (28.7%) and ST2 (13.8%). All the strains of L. monocytogenes were grouped in Lineages I and II. Conclusions: A great genetic variability was observed in the strains of L. monocytogenes analyzed, being predominant the ST1 and ST2, both belonging to Lineage I. Our results contribute to know the population structure of this pathogen in Chile and its presence in clinical samples, food and the environment.

Clinical and microbiological characteristics of community-acquired pneumonia associated with Streptococcus pneumoniae in adult patients in Mexico / Características clínicas y microbiológicas de la neumonía adquirida en la comunidad asociada con Streptococcus pneumoniae en pacientes adultos en México

The aim of this study was to assess the risk factors and clinical and microbiological characteristics of community-acquired pneumonia (CAP) in adult patients in Mexico. Streptococcus pneumoniae classified as the causative agent of CAP in adult patients and patients with invasive S. pneumoniae isolates presented to three tertiary teaching hospitals during the 15-year study period were selected. Serotyping and susceptibility testing were performed for all included isolates. Clinical and demographic data were recorded. A total of 96 patients infected with S. pneumoniae (71 with CAP, 25 with invasive disease) were included. The CAP group involved more males (74.6%) than the invasive disease group (p = 0.03). Head trauma was more common in the CAP group (21.1%) than in the invasive disease group (4.0%; p = 0.03). The most prevalent serotype was 19A, followed by serotypes 3 and 23F. After the introduction of the heptavalent conjugated pneumococcal vaccine (PCV7), the prevalence of included serotypes declined significantly; no such change was found after the introduction of the PCV13 vaccine, including in the prevalence of serotype 19A. Susceptibility to all antimicrobials tested except vancomycin declined over the study period. In conclusion, head trauma was the most common comorbidity in the CAP group. The most prevalent serotype was 19A. Decreased susceptibility to most antimicrobials tested was observed.

El objetivo de este estudio fue evaluar los factores de riesgo y las características clínicas y microbiológicas de la neumonía adquirida en la comunidad (NAC) en pacientes adultos en México. Se seleccionaron pacientes adultos con NAC con Streptococcus pneumoniae como agente causal y pacientes con aislamientos invasivos de S. pneumoniae que concurrieron a tres hospitales de enseñanza de tercer nivel durante el período de estudio de 15 anos (2000-2015). Se realizaron pruebas de serotipificación y sensibilidad con todos los aislados incluidos. Se colectaron los datos clínicos y demográficos. Se incluyeron en total 96 pacientes infectados con S. pneumoniae (71 con NAC y 25 con enfermedad invasiva). El grupo con NAC incluía más varones (74,6%) que el grupo de enfermedad invasiva (p = 0,03). El traumatismo craneoencefálico fue más frecuente en el grupo NAC (21,1%) queen el grupo con enfermedad invasiva (4,0%; p = 0,03). El serotipo más frecuente fue 19A, seguido de los serotipos 3 y 23F. Después de la introducción de la vacuna antineumocócica conjugada heptavalente (PCV7), la prevalencia de los serotipos incluidos en aquella disminuyó significativamente; no sucedió lo mismo después de la introducción de la PCV13, incluso en relación con la prevalencia del serotipo 19A. La sensibilidad a todos los antimicrobianos evaluados, excepto la vancomicina, disminuyó durante el período de estudio. En conclusión, el traumatismo craneoencefálico fue la comorbilidad más frecuente en el grupo con NAC. El serotipo más frecuente fue el 19A, y se observó disminución de la sensibilidad a la mayoría de los antimicrobianos probados a lo largo del período considerado.

Infecciones por Escherichia coli productora de toxina Shiga O121: H19 en pacientes atendidos en Mar del Plata / Infections caused by Escherichia coli producing Shiga O121: H19 toxin in patients treated in Mar del Plata

Escherichia coli productora de toxina Shiga (STEC) O157:H7 es el serotipo más frecuentemente identificado como agente causal de colitis hemorrágica y síndrome urémico hemolítico (SUH), aunque se han descripto más de 100 serotipos con potencial patogénico similar. El objetivo del trabajo fue describir casos de enfermedad humana asociados a la infección por STEC O121:H19, atendidos en la ciudad de Mar del Plata y establecer la relación genética de los aislamientos mediante técnicas de epidemiología molecular. Se observó un amplio espectro en la severidad clínica de los ocho casos estudiados: dos fueron asintomáticos (contactos de SUH), un paciente tuvo diarrea sanguinolenta, y cinco presentaron SUH. Uno de los pacientes con SUH falleció. Las cepas O121:H19 portadoras del genotipo stx2a/eae/ehxA fueron sensibles a los antibióticos ensayados y presentaron por electroforesis en gel de campo pulsado (Xbal-PFGE) distintos patrones de macrorrestricción, con similitud del 84,25%. El patrón AREXKX01.0072, detectado en un SUH y en su contacto, es nuevo en la Base de Datos Nacional de STEC no-O157 de la Argentina. La utilización de métodos estandarizados de detección y tipificación de STEC permite a los laboratorios de referencia monitorear la frecuencia temporal y la distribución geográfica de las cepas circulantes para la prevención y control de estos patógenos asociados a enfermedad humana.

Shiga toxin-producing Escherichia coli (STEC) O157:H7 is the most frequent serotype identified as causative agent of sporadic cases and outbreaks of diarrhea with or without blood, hemorrhagic colitis and hemolytic uremic syndrome (HUS), although more than 100 serotypes have been described of similar pathogenic potential. The aim of the study was to describe cases of human disease associated with STEC O121:H19 infections, assisted in Mar del Plata City, and to establish the genetic relationship of the isolates by molecular epidemiology techniques. A wide spectrum was observed in the clinical severity of the eight cases studied: two were asymptomatic (contacts of HUS), one patient had bloody diarrhea, and five cases presented HUS. One HUS case died. All STEC O121:H19 strains carried the stx2a/eae/ehxA genotype, were sensitive to all antibiotics tested and showed different macrorestriction patterns by pulsed-field gel electrophoresis (Xbal-PFGE), with 84.25% similarity. The pattern AREXKX01.0072, detected in a HUS case and in his contact, is new in the Argentine National Database of non-O157 STEC. The use of standardized methods for detection and typing of STEC allows reference laboratories to monitor the temporal frequency and geographical distribution of circulating strains for the prevention and control of these pathogens associated with human diseases.

Escherichia coli produtora de toxina Shiga (STEC) O157:H7 é o sorotipo mais frequentemente identificado como o agente causador de colite hemorrágica e síndrome hemolítica urêmica (SHU), embora tenham sido descritas mais de 100 sorotipos com potencial patogênico semelhantes. O objectivo foi o de descrever os casos de doença humana associadas com a infecção por STEC O121:H19, assistido, na cidade de Mar del Plata e estabelecer relação genética de isolados utilizando epidemiologia molecular. Um amplo espectro foi observado na severidade clínica dos oito casos estudados, dois eram assintomáticos (contacto SHU), uma paciente teve diarreia com sangue, e cinco tiveram SHU. Um caso de SHU faleceu. As cepas O121:H19 portaram o genótipo stx2a/eae/ehxA, foram sensíveis aos antibióticos testados e apresentaram, por eletroforese em gel de campo pulsado (Xbal-PFGE), diferentes padrões de macrorestrição, com similaridade de 84,25%. O padrão AREXKX01.0072 detectado em SHU e em seu contato, é novo para a Base de Dados Nacional de STEC não-O157 na Argentina. O uso de métodos padrão de detecção e tipagem de STEC permite os laboratórios de referência monitorar frequência temporal e distribuição geográfica de estirpes circulantes para a prevenção e controlo destes agentes patogénicos associados com a doença humana.

Clinical and microbiological characteristics of community-acquired pneumonia associated with Streptococcus pneumoniae in adult patients in Mexico.

The aim of this study was to assess the risk factors and clinical and microbiological characteristics of community-acquired pneumonia (CAP) in adult patients in Mexico. Streptococcus pneumoniae classified as the causative agent of CAP in adult patients and patients with invasive S. pneumoniae isolates presented to three tertiary teaching hospitals during the 15-year study period were selected. Serotyping and susceptibility testing were performed for all included isolates. Clinical and demographic data were recorded. A total of 96 patients infected with S. pneumoniae (71 with CAP, 25 with invasive disease) were included. The CAP group involved more males (74.6%) than the invasive disease group (p=0.03). Head trauma was more common in the CAP group (21.1%) than in the invasive disease group (4.0%; p=0.03). The most prevalent serotype was 19A, followed by serotypes 3 and 23F. After the introduction of the heptavalent conjugated pneumococcal vaccine (PCV7), the prevalence of included serotypes declined significantly; no such change was found after the introduction of the PCV13 vaccine, including in the prevalence of serotype 19A. Susceptibility to all antimicrobials tested except vancomycin declined over the study period. In conclusion, head trauma was the most common comorbidity in the CAP group. The most prevalent serotype was 19A. Decreased susceptibility to most antimicrobials tested was observed.

Presencia de serotipos de Campylobacter jejuni O:19 en la cadena avícola Argentina / Campylobacter jejuni O:19 serotype in Argentine poultry meat supply chain

Las especies termotolerantes de Campylobacter han tomado gran relevancia en los últimos años debido a que son los principales agentes zoonóticos causantes de enfermedades transmitidas por alimentos. Adicionalmente, Campylobacter jejuni serotipo O:19 ha sido relacionado con el desarrollo del síndrome posdiarreico de Guillain-Barré. El objetivo de este trabajo fue determinar la proporción de cepas de C. jejuni que se corresponden con el serotipo O:19 dentro de las aisladas en diferentes etapas de 3 cadenas de producción de carne aviar en la provincia de Santa Fe. Se observó que el 18% del total de cepas de C. jejuni recuperadas (10/55) pertenecían al serotipo O:19; estas se aislaron en 4 de las 5 etapas de producción de carne aviar elegidas a los fines de este estudio. Este hallazgo da cuenta de un riesgo importante para la salud pública de los consumidores y debería ser considerado en los estudios epidemiológicos de Campylobacter, para implementar en forma urgente medidas de control sobre este microorganismo.

Thermotolerant species of Campylobacter have been focus of attention in the last years because they are the major agent causing zoonotic foodborne diseases. In addition, Campylobacter jejuni O:19 serotype was associated with Guillain Barré syndrome. The aim of this study was to determine the proportion of C. jejuni O:19 serotype isolated at different stages of three poultry meat supply chain in Santa Fe, Argentina. The analysis showed that 18% of isolated C. jejuni belong to serotype O:19. It was also determined that the presence of these strains is given in almost all production stages. These results reflect a significant risk to public health of consumers. Epidemiological studies of Campylobacter should be considered to establish a risk manager policy.

[Campylobacter jejuni O:19 serotype in Argentine poultry meat supply chain]. / Presencia de serotipos de Campylobacter jejuni O:19 en la cadena avícola Argentina.

Thermotolerant species of Campylobacter have been focus of attention in the last years because they are the major agent causing zoonotic foodborne diseases. In addition, Campylobacter jejuni O:19 serotype was associated with Guillain Barré syndrome. The aim of this study was to determine the proportion of C. jejuni O:19 serotype isolated at different stages of three poultry meat supply chain in Santa Fe, Argentina. The analysis showed that 18% of isolated C. jejuni belong to serotype O:19. It was also determined that the presence of these strains is given in almost all production stages. These results reflect a significant risk to public health of consumers. Epidemiological studies of Campylobacter should be considered to establish a risk manager policy.

Opinión del Comité Consultivo de Inmunizaciones Sociedad Chilena de Infectología: Vacuna neumocóccica conjugada en niños y la emergencia de serotipo 19A / Statement of the Advisory Immunization Committee of the Chilean Society of Infectious Diseases on the emergence of serotype 19A pneumococcal infection and the use of pneumococcal conjugated vaccine in Chilean children

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.