Sensibilidad analítica de un ensayo de PCR múltiple para la identificación de cepas de campo o vacunales de brucella abortus en leche y nódulos linfáticos de bovinos

Abstract

Bovine brucellosis is an infectious-transmissible disease caused mainly by Brucella abortus, has a worldwide distribution and a negative socioeconomic effect due to losses caused by abortions, birth of weak calves, reduction in milk production and infertility in infected cattle, and impact in public health because of its zoonotic nature. For the diagnosis different laboratory methods exist, indirect ones such as agglutination with the antigen stained with Rose of Bengal, ring test in milk, ELISAs, among others, and the direct ones like bacterial isolation, direct immunofluorescence and PCR. In the process of implementing a diagnostic test in a laboratory it is necessary to evaluate and estimate its suitability for its concrete application. It evaluates a series of variables, including the minimum amount of analyte that is detected by the test, this value is known as analytical sensitivity. The case of PCR is not the exception, and the current project was intended to estimate the analytical sensitivity of the multiple PCR assay for use in the identification of Brucella abortus field strains and / or vaccine strains S19 and RB51 in the milk samples and bovine lymph node tissues. As a result it was found that, in milk, strain S19 was amplified the product of 456 bp and strain RB51 the product of 1290 bp was amplified and the limit of detection in the two strains was 1 X 104 CFU/ml. In the case of tissues, it has not been possible to estimate the analytical sensitivity, given the inability of the extraction method to obtain the quality genetic material to be used in the PCR assays and the other side, the non-specificity shown by the primers used. So you have to change the method of total DNA extraction and use other primers or redesign them.