Avaliação de um antígeno comercial de Brucella ovis na padronização de um teste elisa indireto para o diagnóstico da brucelose ovina

Abstract

Brucella ovis infection is a major cause of economic losses to sheep production in the country, considering that in sheep causes epididymitis and infertility in sheep and can cause placentitis. This bacterial agent interferes with fetal nutrition, and causes the birth of weak lambs and underweight, and can cause perinatal mortality. The clinical diagnosis of this disease is difficult, and the serological tests that are most commonly used to detect antibodies against B. ovis are AGID, RFC and ELISA. In view of the need for an efficient test for the diagnosis of ovine brucellosis, this study aimed to standardize enzyme immunoassay using a commercial ELISA antigen of B. ovis. We used the commercial antigen of Kit for the diagnosis of Brucella ovis (agar gel immunodiffusion) of TECPAR Laboratory, consisting of soluble proteins and lipopolysaccharides extracted from bacteria, Reo 198 sample and, a Brucella canis antigen to compare the results with the commercial antigen. To choose the best dilution for use of commercial antigen, it was diluted in the proportions: 1:50; 1:100; 1:200; 1:400 and 1:800. The dilution of B. canis antigen used was 1:200. Choosing the best dilution, 40 positive samples were tested, of which 3 were given by a researcher, proven positive by the IDGA test, and the remainder obtained by dilution of positive control of the commercial kit for the diagnosis of ovine brucellosis TECPAR the laboratory, starting 001/14 and manufacturing JUL/14, and starting 002/15 and manufacturing SET/15. All positive samples passed the following dilutions: Pure antigen, serial dilutions of 1:50, 1:100, 1:200, 1:400, 1:800, 1:1600 and 1:3200 and, 40 proved negative samples in immunodiffusion test in agarose gel (IDGA). The protocol for ELISA is described previously in the literature.From these results, the indirect ELISA test showed 12.5 % and 17.5 % sensitivity, using commercial antigen of B. ovis and B. canis, respectively. Specificity ELISA 's using B. canis antigen was 100 % and Brucella ovis was 92.5%. So it was possible to observe the indirect ELISA capacity using commercial antigen Brucella ovis and antigen Brucella canis, it was found that the latter performed better as compared to the sensitivity and specificity, however, the indication to perform this test using antigen B. ovis is most recommended because of the antigenic specificity.