Evaluación de la técnica PCR anidada para el diagnóstico de la esporotricosis experimental / Technical evaluation of nested PCR for the diagnosis of experimental sporotrichosis

Antecedentes. La esporotricosis causada por el hongo dimorfo Sporothrix schenckii puede presentar una gran diversidad de formas clínicas. El diagnóstico de laboratorio se lleva a cabo por estudio micológico y serológico. Muy pocos estudios se han enfocado a la evaluación de su diagnóstico molecular. Objetivo. Ensayar la técnica de reacción en cadena de la polimerasa (PCR) anidada en el diagnóstico de la esporotricosis experimental en órganos de ratones y compararla con los estudios micológico y serológico. Métodos. Ratones BALB/c fueron inoculados con concentraciones crecientes de las 2 fases morfológicas del hongo. Los animales fueron sacrificados un mes después de la inoculación, evaluándose muestras de hígado, bazo, pulmón y testículo para el estudio micológico (examen directo y cultivo) y molecular por PCR anidada, y muestras de sangre para la captación de anticuerpos específicos contra S. schenckii por inmunodifusión doble. Resultados. Los resultados de patogenicidad con las diferentes concentraciones del hongo, y el aislamiento del mismo por cultivo mostraron pocas diferencias en el estudio de las muestras de los órganos infectados con las 2 fases morfológicas de S. schenckii. En las muestras de ratones inoculados con la fase micelial los porcentajes de positividad del cultivo y examen directo fueron mayores (100 y 37,5%), en comparación con los encontrados con los de levadura (73 y 2%). Sin embargo, en el diagnóstico molecular por PCR anidada, en estas últimas muestras, los porcentajes de positividad fueron mayores (75%), encontrándose con el micelio un 43% de resultados positivos. La detección de anticuerpos específicos fue positiva en el 100% de todos los grupos de ratones infectados. Conclusiones. En el estudio de la esporotricosis experimental en ratones, el cultivo demostró ser una herramienta de gran eficacia, así como también la detección de anticuerpos específicos, mientras que la prueba de PCR anidada y el estudio microscópico resultaron ser de de inferior valor diagnóstico(AU)

Background. Sporotrichosis caused by the dimorphic fungus Sporothrix schenckii can presents in a variety of clinical forms. Routine diagnosis is made by mycology and serology studies. Few investigations have been focused on the evaluation of the molecular diagnosis. Aim. To determine the value of the nested PCR technique for the diagnosis of experimental sporotrichosis in organs of mice, and to compare the results with the established laboratory diagnostic procedures. Methods. BALB/c mice were inoculated with growing concentrations of the 2 morphological phases of the fungus. The infected animals were sacrificed one month later and specimens from liver, spleen, lung and testicle were obtained to perform wet mount, culture and molecular diagnosis by the nested PCR technique. Blood samples were obtained for determination of specific antibodies against S. schenckii by the double immunodiffusion procedure. Results. The pathogenicity observed with the different concentrations of the fungus inoculated and its isolation by culture, showed scarce differences in the study of specimens from organs infected with the 2 morphological phases of S. schenckii. Specimens from organs of mice inoculated with the mycelial phase when studied by wet mount and culture, showed a higher positivity (100 and 37.5%) than those from mice inoculated with the yeast phase (73 and 2%). However, diagnosis by the nested PCR molecular technique applied to the latter specimens showed a higher percentage of positivity (75%) and 43% of positive results coming from animals infected with the mycelial phase. Specific antibody detection was positive in 100% all groups of infected mice. Conclusions. In the study of experimental sporotrichosis in mice, the culture, as well as the antibody detection, was an effective diagnostic procedure, while the nested PCR and microscopic studies had a lower diagnostic value(AU)

[Technical evaluation of nested PCR for the diagnosis of experimental sporotrichosis]. / Evaluación de la técnica PCR anidada para el diagnóstico de la esporotricosis experimental.

BACKGROUND: Sporotrichosis caused by the dimorphic fungus Sporothrix schenckii can presents in a variety of clinical forms. Routine diagnosis is made by mycology and serology studies. Few investigations have been focused on the evaluation of the molecular diagnosis. AIM: To determine the value of the nested PCR technique for the diagnosis of experimental sporotrichosis in organs of mice, and to compare the results with the established laboratory diagnostic procedures. METHODS: BALB/c mice were inoculated with growing concentrations of the 2 morphological phases of the fungus. The infected animals were sacrificed one month later and specimens from liver, spleen, lung and testicle were obtained to perform wet mount, culture and molecular diagnosis by the nested PCR technique. Blood samples were obtained for determination of specific antibodies against S. schenckii by the double immunodiffusion procedure. RESULTS: The pathogenicity observed with the different concentrations of the fungus inoculated and its isolation by culture, showed scarce differences in the study of specimens from organs infected with the 2 morphological phases of S. schenckii. Specimens from organs of mice inoculated with the mycelial phase when studied by wet mount and culture, showed a higher positivity (100 and 37.5%) than those from mice inoculated with the yeast phase (73 and 2%). However, diagnosis by the nested PCR molecular technique applied to the latter specimens showed a higher percentage of positivity (75%) and 43% of positive results coming from animals infected with the mycelial phase. Specific antibody detection was positive in 100% all groups of infected mice. CONCLUSIONS: In the study of experimental sporotrichosis in mice, the culture, as well as the antibody detection, was an effective diagnostic procedure, while the nested PCR and microscopic studies had a lower diagnostic value.