Vigilancia tecnológica e inteligencia competitiva de un desarrollo tecnológico para la detección de Giardia, una innovación en salud

[RESUMEN]. La giardiasis es una enfermedad causada por Giardia duodenalis, protozoario enteropatógeno que también es responsable de la enfermedad diarreica aguda y la gastroenteritis en humanos. Dadas las características de excreción intermitente propias de este parásito, la probabilidad de obtener resultados falsos negativos durante el proceso de diagnóstico es alta. En el Grupo de Parasitología del Instituto Nacional de Salud de Colombia se identificaron proteínas inmunogénicas presentes en quistes y trofozoítos del parásito en aislamientos colombianos de Giardia con potencial comercial y posibilidad de ser patentadas. Se realizó un estudio exploratorio descriptivo a partir de las características de la técnica en estudio, su estado de desarrollo y la viabilidad comercial de la invención. Se encontraron 390 patentes y se seleccionaron cinco invenciones similares que no representaban ningún riesgo frente a una eventual solicitud de patente. De los 36 estuches para el diagnóstico de Giardia disponibles en el mercado y las 21 licencias sanitarias otorgadas hasta diciembre del 2017, sólo cuatro y tres, respectivamente, proponen técnicas similares a la de la estudiada, pero ninguna de ellas cuenta con un registro de patente relacionado. La técnica en desarrollo es innovadora y puede aplicarse en el campo de la salud pública en la Región de las Américas con beneficios previsibles.

[ABSTRACT]. Giardiasis is a disease caused by Giardia duodenalis, an intestinal protozoan that causes acute diarrhea and gastroenteritis in humans. Given the characteristic intermittent excretion of this parasite, there is a high probability of false negative results during diagnosis. The Parasitology Group of Colombia’s National Institute of Health identified immunizing proteins present in the parasite’s cysts and trophozoites in Colombian Giardia isolates with commercial and patentability potential. A descriptive exploratory study was conducted that focused on characteristics of the technique under study, its state of development, and the commercial viability of the invention. A total of 390 patents were found and five similar inventions were selected that did not pose any risk regarding an eventual patent application. Of the 36 Giardia diagnostic kits available on the market and the 21 health licenses granted as of December 2017, only four and three, respectively, offer techniques similar to the technique studied, but none of them has a related patent on record. The technique under development is innovative and can be applied in the field of public health in the Region of the Americas with foreseeable benefits.

[RESUMO]. A giardíase é uma doença causada pela Giardia duodenais, protozoário enteropatogênico causador de doença diarreica aguda e gastroenterite em seres humanos. Como uma das características deste parasita é a excreção intermitente, a probabilidade de se obter resultados falso-negativos no processo diagnóstico é alta. O Grupo de Parasitologia do Instituto Nacional de Saúde da Colômbia identificou proteínas imunogênicas presentes em cistos e trofozoítos do parasita em isolados colombianos de Giardia com potencial comercial e possibilidade de patenteamento. Foi realizado um estudo exploratório descritivo das características da técnica em estudo, situação de desenvolvimento e viabilidade comercial da invenção. Foram encontradas 390 patentes e selecionadas cinco invenções similares sem risco de eventual pedido de patente. Dos 36 kits de diagnóstico de Giardia comercializados e 21 licenças sanitárias concedidas até dezembro de 2017, apenas quatro kits e três licenças de produtos empregam técnicas semelhantes à estudada, mas nenhum deles tem um registro de patente relacionado. A técnica em desenvolvimento é inovadora e pode ser empregada em saúde pública na Região das Américas com benefícios esperados.

Detection of Giardia duodenalis antigen in human fecal eluates by enzyme-linked immunosorbent assay using polyclonal antibodies

The present study developed and standardized an enzime-linked immunosorbent assay (ELISA) to detect Giardia antigen in feces using rabbit polyclonal antibodies. Giardia cysts were purified from human fecal samples by sucrose and percoll gradients. Gerbils (Meriones unguiculatus) were infected to obtain trophozoites. Rabbits were inoculated with either cyst or trophozoite antigens of 14 Colombian Giardia isolates to develop antibodies against the respective stages. The IgG anti-Giardia were purified by sequential caprylic acid and ammonium sulfate precipitation. A portion of these polyclonal antibodies was linked to alkaline phosphatase (conjugate). One hundred and ninety six samples of human feces, from different patients, were tested by parasitologic diagnosis: 69 were positive for Giardia cysts, 56 had no Giardia parasites, and 71 revealed parasites other than Giardia. The optimal concentration of polyclonal antibodies for antigen capture was 40 æg/ml and the optimal conjugate dilution was 1:100. The absorbance cut-off value was 0.24. The parameters of the ELISA test for Giardia antigen detection were: sensitivity, 100 percent (95 percent CI: 93.4-100 percent); specificity, 95 percent (95 percent CI: 88.6-97.6 percent); positive predictive value, 91 percent (95 percent CI: 81.4-95.9 percent); and negative predictive value, 100 percent (95 percent CI: 96.1-100 percent). This ELISA will improve the diagnosis of Giardia infections in Colombia and will be useful in following patients after treatment

Detection of Giardia duodenalis antigen in human fecal eluates by enzyme-linked immunosorbent assay using polyclonal antibodies.

The present study developed and standardized an enzime-linked immunosorbent assay (ELISA) to detect Giardia antigen in feces using rabbit polyclonal antibodies. Giardia cysts were purified from human fecal samples by sucrose and percoll gradients. Gerbils (Meriones unguiculatus) were infected to obtain trophozoites. Rabbits were inoculated with either cyst or trophozoite antigens of 14 Colombian Giardia isolates to develop antibodies against the respective stages. The IgG anti-Giardia were purified by sequential caprylic acid and ammonium sulfate precipitation. A portion of these polyclonal antibodies was linked to alkaline phosphatase (conjugate). One hundred and ninety six samples of human feces, from different patients, were tested by parasitologic diagnosis: 69 were positive for Giardia cysts, 56 had no Giardia parasites, and 71 revealed parasites other than Giardia. The optimal concentration of polyclonal antibodies for antigen capture was 40 g/ml and the optimal conjugate dilution was 1:100. The absorbance cut-off value was 0.24. The parameters of the ELISA test for Giardia antigen detection were: sensitivity, 100% (95% CI: 93.4-100%); specificity, 95% (95% CI: 88.6-97.6%); positive predictive value, 91% (95% CI: 81.4-95.9%); and negative predictive value, 100% (95% CI: 96.1-100%). This ELISA will improve the diagnosis of Giardia infections in Colombia and will be useful in following patients after treatment.

Seroprevalencia de infección por Trypanosoma cruzi en población urbana y rural de Guateque, Colombia / Seroprevalence of infection by Trypanosoma cruzi in urban and rural population of Guateque, Colombia

Se realizó un estudio de corte transversal para determinar la seroprevalencia de la infección chagásica en personas que viven en zona urbana y rural de Guateque (Boyacá). Se detectaron anticuerpos contra Trypanosoma cruzi mediante la técnica de ELISA. Se determinó la prevalencia de infección por género, grupos etáreos decenales y ubicación urbana y rural. Se calcularon los riesgos ajustados de infección mediante regresión logística no condicional incluyendo las variables mencionadas. Las prevalencias de infección variaron entre O y el 88 por ciento siendo en la zona rural del 34.5 por ciento y en la urbana del 5.3 por ciento. La prevalencia de infección por grupos etáreos no se comportó como en otros estudios. La correlación entre edad y tiempo vivido en la zona por grupo etáreo es baja pero positiva en todos los grupos de edad excepto en los de 20-29 y 30-39, en los que fue negativa. Como hallazgo interesante se encontró un OR de 0.6 para el género masculino

Prevalence of Trypanosoma cruzi and Leishmania chagasi infection and risk factors in a Colombian indigenous population

This study was carried out in order to obtain base-line data concerning the epidemiology of American Visceral Leishmaniasis and Chagas's Disease in an indigenous population with whom the government is starting a dwelling improvement programme. Information was collected from 242 dwellings (1,440 people), by means of house to house interviews about socio-economic and environmental factors associated with Leishmania chagasi and Trypanosoma cruzi transmission risk. A leishmanin skin test was applied to 385 people and 454 blood samples were collected on filter paper in order to detect L. chagasi antibodies by ELISA and IFAT and T. cruzi antibodies by ELISA. T. cruzi seroprevalence was 8.7 percent by ELISA, L. chagasi was 4.6 percent and 5.1 pecent by IFAT and ELISA, respectively. ELISA sensitivity and specificity for L. chagasi antibodies were 57 percent and 97.5 percent respectively, as compared to the IFAT. Leishmanin skin test positivity was 19 percent. L. chagasi infection prevalence, being defined as a positive result in the three-immunodiagnostic tests, was 17.1 percent. Additionally, 2.7 percent of the population studied was positive to both L. chagasi and T. cruzi, showing a possible cross-reaction. L. chagasi and T. cruzi seropositivity increased with age, while no association with gender was observed. Age (p<0.007), number of inhabitants (p<0.05), floor material (p<0.03) and recognition of vector (p<0.01) were associated with T. cruzi infection, whilst age ( p<0.007) and dwelling improvement (p<0.02) were associated with L. chagasi infection. It is necessary to evaluate the long-term impact of the dwelling improvement programme on these parasitic infections in this community

Evaluación del efecto del ácido nalidíxico, ampicilina, kanamicina, penicilina G y polimixina B en los cultivos de promastigotes de leishmania / Evaluation the effect of nalidixic acid, ampicillin, kanamycin, penicillin G and polimyxin B in leishmania promastigote cultures

Se evaluó el efecto de diferentes concentraciones de ácido nalidíxico, ampicilina, kanamicina, penicilina G y polimixina B, sobre la población de promastigotes de Leishmania braziliensis braziliensis, Leishmania donovani chagasi y Leishmania mexicana amazonensis in vitro. La penicilina G y la ampicilina se pueden utilizar hasta concentraciones 1000 ug/ml y 500 ug/ml respectivamente en cultivo de promastigotes de cualquier cepa de Leishmania sin que éstos se afecten. La polimixina B disminuye la población de promastigotes por lo cual es preferible no usarse en cultivos de Leishmania. El ácido nalidíxico y kanamicina pueden ser utilizados in vitro pero teniéndose en cuenta la especie de Leishmania y la concentración de antimicrobiano recomendado para la misma

Crioconservación de toxoplasma gondii / Toxoplasma gondii: cryopreservation

Toxoplasma gondii fue crioconservado en nitrógeno líquido usando como preservativo glicerol al 10 por ciento con el fin de mantener el protozoo por un largo período de tiempo. El descongelamiento de T. gondii se llevó a cabo, cuando los parásitos fueron requeridos para uso como antígeno, a los 10, 40 y 270 días siguientes a su crioconservación. La viabilidad y patogenicidad del parásito fue confirmada in vivo. La crioconservación de T. gondii disminuyó los costos de mantenimiento in vivo y de recursos humanos tanto en el bioterio como en el laboratorio