Abundance, composition and natural infection of Anopheles mosquitoes from two malaria-endemic regions of Colombia / Abundancia, composición e infección natural de mosquitos Anopheles en dos regiones endémicas para malaria en Colombia

Abstract Introduction: In Colombia there are three Anopheles species implicated in malaria transmission as primary vectors; however, the local role of some Anopheles species must still be defined. Objective: To determine the abundance, composition and natural infection rates for Anopheles mosquitoes with Plasmodium spp. in two malaria-endemic regions of Colombia. Materials and methods: Anopheles mosquitoes were collected using the human-landing catches and while resting in livestock corrals in nine localities of two malaria-endemic regions of Colombia. Mosquitoes were morphologically identified and confirmed by PCR-RFLP-ITS2. Identified mosquitoes were processed and tested for Plasmodium parasite infection by ELISA and ssrRNA-based nested PCR. Results: We collected 1,963 Anopheles mosquitoes corresponding to nine species. The most abundant species were Anopheles nuneztovari (53.5%) and A. darlingi (34.5%), followed by A. triannulatus s.l. (6%), and other species (˜5.9%). Three species were naturally infected with Plasmodium spp.: A. darlingi, A. nuneztovari and A. triannulatus s.l. Conclusions: Natural infection of A. darlingi and A. nuneztovari indicate that these malaria vectors continue to be effective carriers of Plasmodium in the localities under study in Valle del Cauca and Chocó. Additionally, the infected A. triannulatus s.l. collected in livestock corrals in the locality of the department of Córdoba suggests the need for further studies to define the epidemiological importance of this species given its abundance and opportunistic anthropophilic behavior.

Resumen Introducción. En Colombia hay tres especies de mosquitos Anopheles implicadas como vectores primarios en la transmisión de la malaria o paludismo; sin embargo, el rol local de algunas especies de Anopheles aún debe determinarse. Objetivo. Determinar la abundancia, la composición y la infección natural de mosquitos anofelinos con Plasmodium spp. en dos regiones endémicas de malaria en Colombia. Materiales y métodos. Se recolectaron mosquitos del género Anopheles usando los métodos de recolección con cebo humano y en reposo en corrales de ganado vacuno, en nueve localidades de dos regiones endémicas para malaria en Colombia. Los especímenes se identificaron morfológicamente y se confirmaron por reacción en cadena de la polimerasa (PCR) de los polimorfismos en la longitud de los fragmentos de restricción (Restriction Fragment Length Polymorphism, RFLP) en el espaciador intergénico ribosómico nuclear 2 (Internal Transcribed Spacer, ITS-2) (PCR-RFLPITS2). Los especímenes se procesaron y analizaron mediante ELISA y PCR anidada basada en la subunidad pequeña del ARN ribosómico (small subunit ribosomal RNA, ssrRNA) para determinar la infección por Plasmodium. Resultados. Se recolectaron 1.963 mosquitos Anopheles correspondientes a nueve especies. Anopheles nuneztovari fue la especie predominante (53,5 %), seguida por A. darlingi (34,5 %), A. triannulatus s.l. (6 %) y por otras especies (˜5,9 %). Tres especies se encontraron naturalmente infectadas con Plasmodium spp.: A. darlingi, A. nuneztovari y A. triannulatus s.l. Conclusiones. La infección natural de A. darlingi y A. nuneztovari indica que estos vectores primarios siguen siendo actores principales en la transmisión de malaria en las localidades estudiadas de los departamentos del Valle del Cauca y Chocó. Además, el espécimen A. triannulatus s.l. infectado, recolectado en corrales de animales de la localidad estudiada en el departamento de Córdoba, indica que existe la necesidad de estudios futuros para establecer la importancia epidemiológica de esta especie dada su abundancia y comportamiento antropofílico oportunista.

Molecular identification and genotyping of Streptococcus mutans from saliva samples of children in Medellin, Colombia / Identificación molecular y genotipificación de Streptococcus mutansde muestras de saliva de niños de Medellín, Colombia

Abstract Introduction and objective: Tooth decay is one of the most prevalent infectious diseases of the oral cavity. The aim of this study was to determine the prevalence of Streptoccocus mutans and its genotypes in saliva samples from 6 and 7 year old children with and without dental caries. Materials and methods: Forty seven saliva samples were obtained from 6-7 year-old children, randomly selected from a Public School in Medellin, Colombia. Oral examinations in order to determine the DMF-T Index (Decay, Missing and Filling Teeth) were carried out. Isolates were identified by the Streptoccocus sobrinus and Streptococcus mutans PCR, API 20STREP and 16S rRNA sequence analysis. Genotypes c, e, f and k were detected by PCR. Results: Prevalence of S. mutanswas 14.9%. Of the 47 saliva samples, 57.4% (27) corresponded to children with dental caries, and 8.5% (4) were positive for S. mutans genotype c, 2.1% (1 each) genotype f genotype k, and genotype cand k, respectively. Conclusion: Prevalence of S. mutanswas lower than in previous studies of Colombian children with similar demographic characteristics. Streptoccocusmutans'genotype c, fand kwere found in children with caries but not in the group without caries. This is the first report of S. mutans genotype kin Colombia; this genotype requires further study to clarify its relation with dental caries and cardiovascular disease in Colombia.

Resumen Introducción y objetivo: La caries dental es una de las enfermedades infecciosas de la cavidad oral más comunes en el mundo. El objetivo de este estudio fue determinar la prevalencia de Streptococcus mutansy sus genotipos en muestras de saliva de niños de 6 y 7 años, con y sin caries dental. Materiales y métodos: Cuarenta y siete (47) muestras de saliva fueron obtenidas de niños de 6-7 años, seleccionados aleatoriamente de una escuela pública en Medellín, Colombia. Se realizaron evaluaciones orales para determinar el índice COP-D (número de dientes permanentes cariados, obturados y perdidos). Los aislamientos fueron identificados mediante PCR para diferenciación de S. sobrinusy S. mutans, API-20STREP y análisis de ARNr 16S. Se determinaron mediante PCR los genotipos c e, fy ken las cepas identificadas como S. mutans. Resultados: La prevalencia de S. mutansfue 14,9%. De las 47 muestras de saliva, 57,4% (27) correspondieron a niños con caries dental, y 8,5 % (4), fueron positivas para S. mutans genotipo c, 2,1 % (1 cada una) genotipo f genotipo ky genotipo cy k, respectivamente. Conclusión: La prevalencia de S. mutansfue menor que la reportada en estudios previos de niños colombianos con características demográficas similares. Se encontró presencia de genotipos c, fy kde S. mutansen niños con caries dental, pero no en el grupo de niños sin caries dental. Este es el primer estudio en reportar la presencia del genotipo ken Colombia. Es necesario realizar más investigaciones en nuestro país para aclarar la relación de S. mutans genotipo k con caries dental y enfermedad cardiovascular.

Direct detection of toxigenic Bacillus cereus in dietary complement for children and cassava starch / Detección directa de Bacillus cereus toxigénicos en complementos dietarios para niños y en almidón de yuca / Detecção direta de Bacillus cereus toxigênicos em suplementos alimentares para crianças e amido de mandioca

Bacillus cereus is a food contaminant and a known human pathogen that can cause emetic and diarrheal syndromes. In this study we evaluated the presence of toxigenic B. cereus by multiplex PCR directly in dietary complement for children and cassava starch samples collected on Medellin, Colombia. Of 75 dietary complement for children samples evaluated, 70.7% were contaminated with toxigenic B. cereus and four different toxigenic consortia were detected: I: nheA, hblC, cytK (9.8%), II: nheA, hblC (2%), III: hblC, cytK (41.2%), IV: hblC (47%). Of 75 cassava starch samples, 44% were contaminated with toxigenic B. cereus and four different toxigenic consortia were determined: I: nheA, hblC, cytK (48.5%), II: nheA, hblC, cytK, cesB (3%), III: hblC, cytK (30.3%), IV: hblC (18.2%). In general, in dietary complement for children only enterotoxigenic consortia were detected while in cassava starch the enterotoxigenic consortia predominated over the emetic. Multiplex PCR was useful to detect toxigenic B. cereus contamination allowing direct and simultaneous detection of all toxin genes in foods. This study is the first in Colombia to evaluate toxigenic B. cereus, providing information of importance for microbiological risk evaluation in dried foods.

Bacillus cereus es un contaminante de alimentos conocido por ser patogénico para los humanos, causando síndromes de vómito y diarrea. En este estudio se evaluó la presencia de B. cereus toxigénicos utilizando PCR múltiple directamente en complementos dietarios para niños y en almidón de yuca colectados en Medellín, Colombia. De 75 muestras de complemento dietario para niños, 70,7% estuvieron contaminadas con B. cereus toxigénicos y se detectaron cuatro diferentes consorcios toxigénicos: I: nheA, hblC, cytK (9,8%), II: nheA, hblC (2%), III: hblC, cytK (41.2%), IV: hblC (47%). De 75 muestras de almidón de yuca, 44% estuvieron contaminadas con B. cereus toxigénicos y se determinaron cuatro diferentes consorcios toxigénicos: I: nheA, hblC, cytK (48.5%), II: nheA, hblC, cytK, cesB (3%), III: hblC, cytK (30,3%), IV: hblC (18.2%). En general, en los complementos dietarios para niños sólo se detectaron consorcios enterotoxigénicos, mientras que en el almidón los consorcios enterotoxigénicos predominaron sobre el emético. La PCR múltiple fue de utilidad para detectar contaminación con B. cereus toxigénicos permitiendo la detección directa y simultánea de todos los genes tóxicos en los alimentos. Este estudio es el primero en Colombia en evaluar B. cereus toxigénicos y proporciona información importante para la evaluación de riesgos microbiológicos en los alimentos pulverizados.

Bacillus cereus é um contaminante de alimentos e é conhecido por ser patogénico nos seres humanos ocasionando síndromes de vômitos e diarreia. Neste estudo foi avaliada a presença de B. cereus toxigênicos por PCR multiplex diretamente em complementos da dieta para crianças e amido de mandioca, em amostras coletadas em Medellín, na Colômbia. De 75 amostras dos complementos da dieta para crianças, 70,7% estiveram contaminadas com B. cereus toxigênicos e foram detectados quatro diferentes consórcios: I: nheA, hblC, cytK (9,8%), II: nheA, hblC (2%), III: hblC, cytK (41,2%), IV: hblC (47%). De 75 amostras de amido de mandioca, 44% estiveram contaminadas com B. cereus toxigênicos e quatro consórcios diferentes foram determinados: I: nheA, hblC, cytK (48,5%), II: nheA, hblC, cytK, cesB (3%) III: hblC, cytK (30,3%), IV: hblC (18,2%). Em geral, nos complementos da dieta para crianças foram detectados apenas consórcios enterotoxigênicos, não obstante no amido os consórcios enterotoxigênicos predominaram sobre o emético. A PCR multiplex foi útil para detectar contaminação com B. cereus toxigênico permitindo a detecção direta e simultânea de todos os genes tóxicos em alimentos. Este estudo é o primeiro na Colômbia em avaliar B. cereus toxigênico e providencia informação importante para a avaliação de riscos microbiológicos em alimentos pulverizados.

Molecular evidence for a single taxon, Anopheles nuneztovari s.l., from two endemic malaria regions in Colombia

To elucidate the Anopheles nuneztovari s.l. taxonomic status at a microgeographic level in four malaria endemic localities from Antioquia and Córdoba, Colombia, fragments of the cytochrome oxidase subunit I (COI) and the white gene were used. The COI analysis showed low genetic differentiation with fixation index (F ST) levels between -0.02-0.137 and Nm values between 3-∞, indicating the presence of high gene flow among An. nuneztovari s.l. populations from the four localities. The COI network showed a single most common haplotype, type 1 (n = 55), present in all localities, as the likely ancestral haplotype. Analysis of the white gene showed that An. nuneztovari s.l. populations from both departments grouped with haplotypes 19 and 20, which are part of lineage 3 reported previously. The results of the present study suggest that An. nuneztovari s.l. is a single taxon in the area of the present study.

A new mtDNA COI gene lineage closely related to Anopheles janconnae of the Albitarsis complex in the Caribbean region of Colombia

An understanding of the taxonomic status and vector distribution of anophelines is crucial in controlling malaria. Previous phylogenetic analyses have supported the description of six species of the Neotropical malaria vector Anopheles (Nyssorhynchus) albitarsis s.l. (Diptera: Culicidae): An. albitarsis, Anopheles deaneorum, Anopheles marajoara, Anopheles oryzalimnetes, Anopheles janconnae and An. albitarsis F. To evaluate the taxonomic status of An. albitarsis s.l. mosquitoes collected in various localities in the Colombian Caribbean region, specimens were analyzed using the complete mitochondrial DNA cytochrome oxidase I (COI) gene, the ribosomal DNA (rDNA) internal transcribed spacer 2 (ITS2) region and partial nuclear DNA white gene sequences. Phylogenetic analyses of the COI gene sequences detected a new lineage closely related to An. janconnae in the Caribbean region of Colombia and determined its position relative to the other members of the complex. However, the ITS2 and white gene sequences lacked sufficient resolution to support a new lineage closely related to An. janconnae or the An. janconnae clade. The possible involvement of this new lineage in malaria transmission in Colombia remains unknown, but its phylogenetic closeness to An. janconnae, which has been implicated in local malaria transmission in Brazil, is intriguing.

Species composition and natural infectivity of anthropophilic Anopheles (Diptera: Culicidae) in the states of Córdoba and Antioquia, Northwestern Colombia

Malaria is a serious health problem in the states of Córdoba and Antioquia, Northwestern Colombia, where 64.4 percent of total Colombian cases were reported in 2007. Because little entomological information is available in this region, the aim of this work was to identify the Anopheles species composition and natural infectivity of mosquitoes distributed in seven localities with highest malaria transmission. A total of 1,768 Anopheles mosquitoes were collected using human landing catches from March 2007-July 2008. Ten species were identified; overall, Anopheles nuneztovari s.l. was the most widespread (62 percent) and showed the highest average human biting rates. There were six other species of the Nyssorhynchus subgenus: Anopheles albimanus (11.6 percent), Anopheles darlingi (9.8 percent), Anopheles braziliensis (6.6 percent), Anopheles triannulatus s.l. (3.5 percent), Anopheles albitarsis s.l. and Anopheles oswaldoi s.l. at < 1 percent; and three of the Anopheles subgenus: Anopheles punctimacula, Anopheles pseudopunctipennis s.l. and Anopheles neomaculipalpusat < 1 percent each. Two species from Córdoba, An. nuneztovari and An. darlingi, were found to be naturally infected by Plasmodium vivax VK247, as determined by ELISA and confirmed by nested PCR. All species were active indoors and outdoors. These results provide basic information for targeted vector control strategies in these localities.

Staphylococcus aureus resistente a meticilina: bases moleculares de la resistencia, epidemiología y tipificación / Methycillin-resistant Staphylococcus aureus: molecular bases of resistance; epidemiology, and typification

Staphylococcus aureus es responsable de un amplio espectro de cuadros clínicos que van desde infecciones en la piel y los tejidos blandos hasta enfermedades sistémicas muy graves que amenazan la vida; tiene gran importancia en la comunidad y está comúnmente implicado en infecciones nosocomiales. Además, un alto porcentaje de individuos está colonizado por S. aureus, lo cual constituye un factor de riesgo para su diseminación. S. aureus tiene gran capacidad de adquirir resistencia a los antimicrobianos y en la actualidad se encuentran cepas resistentes a la mayoría de los antibióticos disponibles; en particular, su resistencia a la meticilina, inicialmente en el ambiente hospitalario (HA-MRSA) y posteriormente en la comunidad (CA-MRSA), ha dificultado aún más el control mundial de este microorganismo. Los estudios de epidemiología molecular han permitido entender mejor las relaciones evolutivas de las cepas y definir el origen de los clones durante brotes epidémicos. En Colombia se sabe poco sobre la epidemiología de S. aureus y aún menos sobre su comportamiento en la comunidad. Por ello, estudios de vigilancia epidemiológica que involucren la tipificación molecular de las cepas permitirán comprender mejor su epidemiología y establecer estrategias más certeras de tratamiento y control.

Staphylococcus aureus is responsible for a wide variety of clinical manifestations ranging from skin and soft tissue infections to severe systemic and life threatening diseases; it is of relevance in the community and is commonly associated with nosocomial infections. Additionally, a high percentage of the population is colonized by S. aureus, which constitutes a risk factor for its dissemination. S. aureus has great capacity to acquire antimicrobial resistance, and currently there are resistant strains to the majority of available antibiotics; in particular, its resistance to methycillin, initially in the hospital environment (Hospital associated methycillin resistant S. aureus, HA-MRSA) and later in the community (Community acquired methycillin resistant S. aureus, CA-MRSA), has made even more difficult the worldwide control of this microorganism. Molecular epidemiological studies have provided a better understanding of the evolutionary relationships of the strains, and the definition of the clonal source during epidemic outbreaks. In Colombia, very little is known about S. aureus epidemiology and even less about its behavior in the community. Therefore, studies based on epidemiological surveillance, involving molecular typing, will lead to a better understanding of its epidemiology, making it possible the design of more assertive control strategies.