Aplicación de un ensayo de PCR convencional múltiple para la detección y diferenciación de cepas de campo y cepas vacunales S19 y RB51 de Brucella abortus en muestras biológicas de bovinos

Abstract

Bovine Brucellosis is an infectious-transmissible disease of global distribution, caused by a bacterium of the genus Brucella. This disease is characterized by abortions in the last third of gestation and reduced fertility, representing a serious economic and sanitary problem. The objective of this work was to evaluate a multiplex PCR assay for the diagnosis of Brucella abortus infection in milk and lymph node samples from seropositive and seronegative bovines distinguishing field strains from vaccine strains S19 and RB51. For serology (Rose Bengal) blood samples were collected from 200 animals, of which 82 cows were in milk production from which milk samples for PCR were taken, plus 69 samples of lymph node tissue (right and / or left prescapular and supramammary). Eight percent of the samples were found to be seropositive by rose bengal test, whereas only 1.2% of the samples resulted positive using the multiplex PCR, corresponding to a milk sample that presented a 456 bp amplification band, coincident with the expected amplicon length of the S19 vaccine strain. The remaining milk samples and in the tissue samples produced several thin bands of different sizes, being nonspecific amplifications, so it is concluded that the multiplex PCR evaluated in this study was not applicable for diagnosis with the primers used.