Analytical performance evaluation of a rapid immunochromatographic test for the diagnosis of bovine brucellosis based on a recombinant BP26 protein

ABSTRACT Brucellosis is an important bacterial disease of global distribution with zoonotic potencial. Serological tests used in Brazil for diagnosis of bovine brucellosis, including the Rose Bengal test (RBT), 2-mercaptoethanol (2-ME), fluorescent polarization (FPA), and complement fixation (FC), are based on the smooth lipopolysaccharide antigen (S-LPS) of Brucella abortus. The aim of this study was to evaluate a recombinant BP26 protein used as antigen in a rapid lateral flow immunochromatographic assay (rBP26-LFIA) for serological diagnosis of bovine brucellosis. Analytical performance of rBP26-LFIA was evaluated in positive and negative bovine serum samples previously characterized by RBT and 2-ME. Estimates of analytical sensitivity and specificity were 73.91% and 97.14%, respectively. Bovine sera reactive to Neospora, Trypanosoma vivax or Leptospira were used to assess specificity because these diseases are commonly associated with abortion in cattle. In addition to a possible cross-reaction induced by commercial vaccines against Leptospira in serological tests for bovine brucellosis using S-LPS as an antigen. In conclusion, rBP26-LFIA, with its current standardization, had good analytical performance. However, a future evaluation of diagnostic performance by rBP26-LFIA with samples from regions with known prevalence is necessary for its recommendation for use in the Brazilian program for the control and eradication of bovine brucellosis.