RESUMEN
Leishmania parasites cause leishmaniasis, one of the most epidemiologically important neglected tropical diseases. Leishmania exhibits a high ability of developing drug resistance, and drug resistance is one of the main threats to public health, as it is associated with increased incidence, mortality, and healthcare costs. The antimonial drug is the main historically implemented drug for leishmaniasis. Nevertheless, even though antimony resistance has been widely documented, the mechanisms involved are not completely understood. In this study, we aimed to identify potential metabolite biomarkers of antimony resistance that could improve leishmaniasis treatment. Here, using L. tropica promastigotes as the biological model, we showed that the level of response to antimony can be potentially predicted using 1H-NMR-based metabolomic profiling. Antimony-resistant parasites exhibited differences in metabolite composition at the intracellular and extracellular levels, suggesting that a metabolic remodeling is required to combat the drug. Simple and time-saving exometabolomic analysis can be efficiently used for the differentiation of sensitive and resistant parasites. Our findings suggest that changes in metabolite composition are associated with an optimized response to the osmotic/oxidative stress and a rearrangement of carbon-energy metabolism. The activation of energy metabolism can be linked to the high energy requirement during the antioxidant stress response. We also found that metabolites such as proline and lactate change linearly with the level of resistance to antimony, showing a close relationship with the parasite's efficiency of drug resistance. A list of potential metabolite biomarkers is described and discussed.
Asunto(s)
Antimonio/toxicidad , Antiprotozoarios/toxicidad , Resistencia a Medicamentos , Leishmania tropica/metabolismo , Metaboloma , Metabolismo Energético , Leishmania tropica/efectos de los fármacos , Presión Osmótica , Estrés OxidativoRESUMEN
Hantavirus cardiopulmonary syndrome (HPS) has gained importance in Latin America as an emerging disease, with reports of about 4000 HPS cases; however, this is probably an underestimate because of limited surveillance programs and diagnostic tools to confirm HPS. In order to address this issue and develop better serosurveillance capability, we evaluated three recombinant peptides from the Necoclí virus (NECV) nucleocapsid in antibody-capture ELISA. We cloned and expressed antigens representing the whole NECV nucleocapsid protein (NECV-rN), the immunodominant domain (NECV-rN100), and a serospecific domain (NECV-rN428), and then we compared these antigens in ELISA to detect IgG antibodies to NECV in human sera. We evaluated human sera collected during two epidemiological studies from the area where NECV was discovered. The first group included 609 sera from healthy individuals, and the second one included 89 samples from patients with undifferentiated febrile illness. In these two groups, hantavirus infection had previously been determined by the presence of IgG to Maciel virus (MCLV), a hantavirus closely related to NECV. The number of IgG-positive sera was higher using the Necoclí ELISA with the rN100 protein, which detected antibodies in a higher percentage of healthy individuals, 129/609 (21.2%), as well as in febrile patients, 11/89 (12.3%). In contrast, using MCLV ELISA, 8 of 609 (1.3%) and 4 of 89 (4.5%) samples from healthy and febrile patients, respectively, were seropositive. The agreement between the NECV and MCLV ELISA assays was ≥ 82.3%; however, the kappa indices were weak but statistically significant for rN (0.251 CI; 0.138-0.365) and rN100rN (0.153 CI; 0.084-0.223). The weak kappa indices were attributed to decreased MCLV ELISA assay sensitivity. These results suggest that NECV rN and rN100 have increased specificity and could be further validated for improved diagnosis of hantavirus infections.
Asunto(s)
Ensayo de Inmunoadsorción Enzimática/métodos , Infecciones por Hepadnaviridae/diagnóstico , Orthohepadnavirus/aislamiento & purificación , Adolescente , Animales , Anticuerpos Antivirales/sangre , Niño , Femenino , Infecciones por Hepadnaviridae/sangre , Infecciones por Hepadnaviridae/virología , Humanos , Inmunoglobulina G/sangre , Masculino , Proteínas de la Nucleocápside/inmunología , Orthohepadnavirus/clasificación , Orthohepadnavirus/genética , Orthohepadnavirus/inmunología , Estudios Retrospectivos , Roedores/sangre , Roedores/virología , Sensibilidad y EspecificidadRESUMEN
BACKGROUND: The location of the microhabitats where immature phlebotomine sand flies of the genus Lutzomyia develop is one of the least-known aspects of this group of medically important insects. For this reason strategies of source reduction approach for their control have not been possible in contrast to other insect vectors (such as mosquitoes), because their juvenile stages in terrestrial microhabitats is difficult to detect. METHODS: Direct examination of soil samples, incubation of substrates and the use of emergence traps were the methods used to identify juvenile stages in 160 soil samples from urban and forest habitats within the foci of Leishmania transmission in Colombia. Immatures collected were identified subsequent from the rearing and emergence of adults using taxonomic keys or the analysis of the mitochondrial marker cytochrome oxidase I. Plant species associated with the natural breeding sites were identified and physicochemical properties of the soils were analyzed. RESULTS: A total of 38 (23.7%) sampling sites were identified as breeding sites, 142 phlebotomine sand flies were identified, belonging to 13 species of the genus Lutzomyia and two of Brumptomyia. The greatest numbers of immature were found within the tabular roots (51 immature sand flies from eight positive sites) and bases of trees (35 immature sand flies from 11 sites). The characterization and presence of the tree species (mainly Ceiba pentadra, Anacardium excelsum, Pseudosamanea guachapale) and the physicochemical properties (relative humidity and carbon/nitrogen ratio) of the soils associated with these breeding sites are significant factors in explaining the diversity and abundance of phlebotomine sand flies. CONCLUSIONS: Immature phlebotomine sand flies of the genus Lutzomyia in Colombia can be found in a wide variety of breeding sites rich in organic matter, high relative humidity and are associated with a typical vegetation of each locality. These results provide new perspectives for the study of the ecology of the genus Lutzomyia in Colombia and the development of vector control strategies.
Asunto(s)
Insectos Vectores/parasitología , Leishmania/fisiología , Leishmaniasis/transmisión , Psychodidae/parasitología , Animales , Cruzamiento , Colombia/epidemiología , Ecología , Ecosistema , Femenino , Humanos , Leishmaniasis/parasitología , Masculino , Suelo , ÁrbolesRESUMEN
Most studies on Staphylococcus aureus have focused on the molecular epidemiology of methicillin-resistant S. aureus (MRSA) infections. In contrast, little information is available regarding the molecular epidemiology of currently circulating methicillin-susceptible S. aureus (MSSA) isolates in hospital settings, an epoch when the epidemiology of S. aureus has undergone significant changes. We conducted a cross-sectional study to compare the clinical, epidemiological, and genetic characteristics of MSSA and MRSA isolates at 3 tertiary-care hospitals in Medellín, Colombia, from February 2008 to June 2010. The infections were classified according to the Centers for Disease Control and Prevention (CDC) definitions. Genotypic analysis included spa typing, multilocus sequence typing (MLST) and staphylococcal cassette chromosome (mec) (SCCmec) typing. A total of 810 patients was enrolled. One hundred infections (12.3%) were classified as community-associated (31 CA-MSSA, 69 CA-MRSA), 379 (46.8%) as healthcare-associated community-onset (136 HACO-MSSA, 243 HACO-MRSA), and 331 (40.9%) as healthcare-associated hospital-onset (104 HAHO-MSSA, 227 HAHO-MRSA). Genotype analyses showed a higher diversity and a more varied spa type repertoire in MSSA than in MRSA strains. Most of the clinical-epidemiological characteristics and risk factors evaluated did not allow for discriminating MRSA- from MSSA-infected patients. The lack of equivalence among the genetic backgrounds of the major MSSA and MRSA clones would suggest that the MRSA clones are imported instead of arising from successful MSSA clones. This study emphasizes the importance of local surveillance to create public awareness on the changing S. aureus epidemiology.
Asunto(s)
Infección Hospitalaria/epidemiología , Infección Hospitalaria/microbiología , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/genética , Staphylococcus aureus/aislamiento & purificación , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Análisis por Conglomerados , Colombia/epidemiología , Infección Hospitalaria/patología , Estudios Transversales , Femenino , Variación Genética , Genotipo , Humanos , Lactante , Recién Nacido , Masculino , Resistencia a la Meticilina , Persona de Mediana Edad , Tipificación Molecular , Infecciones Estafilocócicas/patología , Staphylococcus aureus/clasificación , Adulto JovenRESUMEN
BACKGROUND: Recent reports highlight the incursion of community-associated MRSA within healthcare settings. However, knowledge of this phenomenon remains limited in Latin America. The aim of this study was to evaluate the molecular epidemiology of MRSA in three tertiary-care hospitals in Medellín, Colombia. METHODS: An observational cross-sectional study was conducted from 2008-2010. MRSA infections were classified as either community-associated (CA-MRSA) or healthcare-associated (HA-MRSA), with HA-MRSA further classified as hospital-onset (HAHO-MRSA) or community-onset (HACO-MRSA) according to standard epidemiological definitions established by the U.S. Centers for Disease Control and Prevention (CDC). Genotypic analysis included SCCmec typing, spa typing, PFGE and MLST. RESULTS: Out of 538 total MRSA isolates, 68 (12.6%) were defined as CA-MRSA, 243 (45.2%) as HACO-MRSA and 227 (42.2%) as HAHO-MRSA. The majority harbored SCCmec type IVc (306, 58.7%), followed by SCCmec type I (174, 33.4%). The prevalence of type IVc among CA-, HACO- and HAHO-MRSA isolates was 92.4%, 65.1% and 43.6%, respectively. From 2008 to 2010, the prevalence of type IVc-bearing strains increased significantly, from 50.0% to 68.2% (pâ=â0.004). Strains harboring SCCmec IVc were mainly associated with spa types t1610, t008 and t024 (MLST clonal complex 8), while PFGE confirmed that the t008 and t1610 strains were closely related to the USA300-0114 CA-MRSA clone. Notably, strains belonging to these three spa types exhibited high levels of tetracycline resistance (45.9%). CONCLUSION: CC8 MRSA strains harboring SCCmec type IVc are becoming predominant in Medellín hospitals, displacing previously reported CC5 HA-MRSA clones. Based on shared characteristics including SCCmec IVc, absence of the ACME element and tetracycline resistance, the USA300-related isolates in this study are most likely related to USA300-LV, the recently-described 'Latin American variant' of USA300.
Asunto(s)
Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/patogenicidad , Infecciones Estafilocócicas/epidemiología , Colombia/epidemiología , Electroforesis en Gel de Campo Pulsado , Humanos , Staphylococcus aureus Resistente a Meticilina/clasificación , Factores de Virulencia/genéticaRESUMEN
BACKGROUND: Transfusion-transmitted leishmaniasis is an increasing problem in areas where visceral and cutaneous leishmaniases are endemic. CASE REPORT: This article reports a case of transfusion-transmitted fatal visceral leishmaniasis (VL) caused by Leishmania (Leishmania) mexicana in a 42-year-old male resident of northwestern Colombia who after developing a terminal renal failure due to lupus nephritis received a renal transplant and multiple transfusions. RESULTS: Multiple intracellular Leishmania amastigotes were demonstrated in both renal biopsy and marrow aspirates. Cultures of the parasite were obtained in NNN medium and the identification of the species was done both by direct immunofluorescence and polymerase chain reaction-restriction fragment length polymorphism. CONCLUSIONS: This is the first report of a VL case produced by L. (L.) mexicana in Colombia, which usually is a dermotropic species. Our report suggests that although leishmaniasis is transmitted by the bite of phlebotomine sand flies, Leishmania parasite may be transmitted by blood transfusion, complicating the clinical course of organ transplant and being fatal.
Asunto(s)
Huésped Inmunocomprometido , Leishmania mexicana/patogenicidad , Leishmaniasis Visceral/etiología , Leishmaniasis Visceral/parasitología , Adulto , Anticuerpos Antiprotozoarios/análisis , Ensayo de Inmunoadsorción Enzimática , Humanos , Leishmania mexicana/inmunología , MasculinoRESUMEN
Assessment of the genetic diversity of Plasmodium falciparum in 110 Colombian isolates revealed that nearly all the parasites in the 97 isolates collected in endemic regions west of the Andes shared the same Pfmsp1 block 2 MAD20-type allelic variant, despite showing high diversity for other genetical markers. Analysis of published data indicated that the prevalence of this allelic variant of a major vaccine candidate antigen was already dominant since 1998. This phenomenon, which had not been hitherto recorded for a malaria blood stage antigen, is of biological and immunological interest but remains unexplained.
Asunto(s)
Variación Genética , Proteína 1 de Superficie de Merozoito/genética , Plasmodium falciparum/genética , Alelos , Animales , Colombia , ADN Protozoario/química , ADN Protozoario/genética , Frecuencia de los Genes , Genotipo , Humanos , Malaria Falciparum/parasitología , Datos de Secuencia Molecular , Plasmodium falciparum/aislamiento & purificación , Análisis de Secuencia de ADNRESUMEN
BACKGROUND: Anopheles albimanus is an important malaria vector in some areas throughout its distribution in the Caribbean and the Pacific regions of Colombia, covering three biogeographic zones of the neotropical region, Maracaibo, Magdalena and Chocó. METHODS: This study was conducted to estimate intra-population genetic diversity, genetic differentiation and demographic history of An. albimanus populations because knowledge of vector population structure is a useful tool to guide malaria control programmes. Analyses were based on mtDNA COI gene sequences and four microsatellite loci of individuals collected in eight populations from the Caribbean and the Pacific regions of Colombia. RESULTS: Two distinctive groups were consistently detected corresponding to COI haplotypes from each region. A star-shaped statistical parsimony network, significant and unimodal mismatch distribution, and significant negative neutrality tests together suggest a past demographic expansion or a selective sweep in An. albimanus from the Caribbean coast approximately 21,994 years ago during the late Pleistocene. Overall moderate to low genetic differentiation was observed between populations within each region. However, a significant level of differentiation among the populations closer to Buenaventura in the Pacific region was observed. The isolation by distance model best explained genetic differentiation among the Caribbean region localities: Los Achiotes, Santa Rosa de Lima and Moñitos, but it could not explain the genetic differentiation observed between Turbo (Magdalena providence), and the Pacific region localities (Nuquí, Buenaventura, Tumaco). The patterns of differentiation in the populations from the different biogeographic provinces could not be entirely attributed to isolation by distance. CONCLUSION: The data provide evidence for limited past gene flow between the Caribbean and the Pacific regions, as estimated by mtDNA sequences and current gene flow patterns among An. albimanus populations as measured by MS loci which may be mainly influenced by semi-permeable natural barriers in each biogeographical region that lead to the genetic differences and effective population sizes detected. The relatively high genetic differentiation in the port city of Buenaventura may be the result of specific ecological conditions, human migration and activities and/or differences in effective population sizes. This knowledge could serve to evaluate and coordinate vector control strategies in these regions of Colombia.
Asunto(s)
Anopheles/genética , ADN Mitocondrial/genética , Complejo IV de Transporte de Electrones/genética , Variación Genética/genética , Insectos Vectores/genética , Repeticiones de Microsatélite/genética , Animales , Anopheles/clasificación , Región del Caribe , Colombia , Demografía , Evolución Molecular , Frecuencia de los Genes/genética , Genotipo , Humanos , Insectos Vectores/clasificación , Malaria/transmisión , Mutación , Reacción en Cadena de la Polimerasa , Polimorfismo Genético , Análisis de Secuencia de ADNRESUMEN
Protozoan parasites are important causative agents of morbidity and mortality throughout the world--a problem further complicated by the emergence of drug resistance in these parasites. Mechanisms of drug resistance include the following: decreased uptake of the drug into the cell, loss of drug activation, alterations in the drug target, and over-expression of a well-known multiple drug transporter proteins. In this review, two critical components of resistance are stressed: (1) the role of ATP binding cassette proteins, such as P-glycoproteins, in mediating drug resistance in Leishmania and other protozoans, followed by development of cross-resistance to many structurally and functionally unrelated drugs, and (2) some concepts concerning the reversal mechanism of multidrug resistance by drugs and natural products. Several modulators or chemosensitizers alter the capacity of P-glycoproteins to maintain subtoxic intracellular drug concentrations. Calcium channel blockers such as verapamil act in this mode; however, high concentrations are required for an efficient and effective inhibition and, in addition, produce undesirable side effects. The discovery of new, natural product modulators of P-glycoproteins is stressed. This category of modulators offer potentially improved efficacy and lowered toxicity for the mammalian host.
Asunto(s)
Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/fisiología , Resistencia a Medicamentos , Leishmania/efectos de los fármacos , Animales , Resistencia a Medicamentos/efectos de los fármacos , Resistencia a Múltiples Medicamentos/genética , Leishmania/genética , FenotipoRESUMEN
Actualmente, los parásitos protozoarios son uno de los principales agentes causantes de morbilidad y mortalidad en el mundo, un problema complicado, además, por la aparición de resistencia a medicamentos en estos organismos. La resistencia a medicamentos observada en parásitos protozoarios se debe a diferentes mecanismos como la disminución de la entrada del medicamento a la célula por cambios en el transportador requerido, la pérdida de la activación del medicamento por parte del hospedero, las alteraciones en el blanco del medicamento y la expresión exagerada del transportador múltiple de medicamentos o glicoproteína P (Pgp). En esta revisión, nos centramos en: 1) el papel de las glicoproteínas P (Pgp) de la familia de proteínas ABC (ATP binding cassette) como los transportadores de múltiples medicamentos en la mediación de resistencia en protozoarios, especialmente en Leishmania, y en el desarrollo de resistencia cruzada para medicamentos estructural y funcionalmente no relacionados, y 2) en algunos conceptos relacionados con los mecanismos moduladores que podrían revertir la resistencia a medicamentos por fármacos y productos naturales. Numerosos moduladores o quimiosensibilizadores son conocidos por alterar la capacidad de las glicoproteínas P para mantener concentraciones intracelulares subtóxicas del medicamento; algunos ejemplos incluyen los bloqueadores de los canales de calcio como el verapamilo; sin embargo, se requieren altas concentraciones para una inhibición eficiente y duradera, las cuales producen efectos adversos indeseables. Por tanto, se necesitan más investigaciones relacionadas con los moduladores naturales para Pgp, los cuales podrían presentar menor toxicidad para el hospedero
Asunto(s)
Leishmania , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP , Resistencia a Múltiples Medicamentos , EucariontesRESUMEN
Metacyclogenesis is a process whereby Leishmania transforms from poorly infective procyclic promastigotes into highly infective metacyclic promastigotes. In nature, metacyclogenesis occurs in the insect vector. This transformation is accompanied by an increased ability to infect and survive in the vertebrate host, where the parasite is attacked by the host's immune system. Metacyclogenesis has also been shown to occur in axenic cultures of promastigotes. Morphological changes in size and shape, and length of flagellum were first associated with differentiation in the insect gut and in different phases of growth in culture. Later, the expression of molecules such as LPG and the surface protease gp63 were associated with this process. These two molecules were observed to undergo qualitative and quantitative modifications as the promastigotes differentiated from procyclic to metacyclic forms. Using cDNA subtractive hybridization-based methods or differential amplification, previously unknown genes tightly linked to metacyclogenesis have been identified. Gene products exclusively expressed in metacyclic promastigotes included a gene B product and Mat-1--a gene associated with metacyclogenesis. Other proteins, Meta-1, SHERP and HASP, were up-regulated during the metacyclic stage. The function and stage-regulated expression of these molecules and their relationship with infectivity are now under investigation.
Asunto(s)
Leishmania/crecimiento & desarrollo , Animales , Antígenos de Protozoos/metabolismo , Glicoesfingolípidos/metabolismo , Leishmania/metabolismo , Leishmania/patogenicidad , Metaloendopeptidasas/metabolismo , Proteínas Protozoarias/genética , Proteínas Protozoarias/metabolismo , VirulenciaRESUMEN
La metaciclogénesis es un proceso que experimentan naturalmente los promastigotes de Leishmania en el tracto digestivo del insecto vector y cuya finaldad es transformar los promastigotes en formas altamente infectivas y capaces de sobrevivir en el hospedero vertebrado, donde es somedido a los ataques por parte del sistema inmne. Se ha demostrado que este fenómeno ocurre también en promastigotes en crecimiento en cultivos axénicos in vitro. El proceso de metaciclogénesis se asoció inicialmente con cambios morfológicos, observándose que los promastigotes cambiaban su forma y tamaño con incremento en la longitud del flagelo. Luego, se logró asociar con este fenómeno la expresión de ciertas moléculas implicadas en virulencia, como el lipofosfoglicano (LPG) y una proteasa de superficie, la gp63. Se demostró que estas moléculas experimentaban cambios tanto cuantitativos como cualitativos a medida que los promastigotes se diferencian de promastigotes procíclicos no infectivos a metacíclicos o infectivos. Hoy en día, mediante técnicas de hibridización substractiva con cADN o de amlificaión diferencial, se han logrado identificar genes cuyo patrón de expresión está íntimante ligado al proceso de metaciclogénesis. Se han identificado moléculas como el producto del gen B y una proteína asociada con la metaciclogénesis (Mat-1), las cuales se expresan exclusivamente en promastigotes metacíclicos, mientras que otras como las proteinas meta-1, SHERP Y HASP se sobrexpresan en los promastigotes metacíclicos. Sin embargo, la función y asociación de estas proteínas con este patrón particular de expresión y virulencia se está empezando a evaluar