Use of recombinant malate dehydrogenase (MDH) and superoxide dismutase (SOD) [CuZn] as antigens in indirect ELISA for diagnosis of bovine brucellosis

• Published in: Journal of microbiological methods Vol. 217-218; p. 106874
• Main Authors: Andrade, Rafaella Silva, Faria, Angélica Rosa, Andrade, Hélida Monteiro, de Sousa Bueno Filho, Júlio Sílvio, Mansur, Herman Sander, Mansur, Alexandra Ancelmo Piscitelli, Lage, Andrey Pereira, Dorneles, Elaine Maria Seles
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.02.2024
• Subjects: Animals; Antibodies, Bacterial; Brucella; Brucellosis - diagnosis; Brucellosis - veterinary; Brucellosis, Bovine; Cattle; Enzyme-Linked Immunosorbent Assay - methods; Female; Malate Dehydrogenase; Recombinant protein; Sensitivity and Specificity; Serodiagnosis; Serologic Tests - methods; Serological tests; Serodiagnosis; Recombinant protein; Serological tests; Brucella
• ISSN: 0167-7012; 1872-8359
• DOI: 10.1016/j.mimet.2023.106874

The objective of this study was to validate an indirect enzyme-linked immunoassay (iELISA) using the recombinant proteins, malate dehydrogenase (MDH) and superoxide dismutase (SOD) [CuZn], as antigens and to evaluate its ability to discriminate antibodies produced by vaccination from those induced by infection in the diagnosis of bovine brucellosis. Sera from six groups were evaluated: G1 – culture-positive animals (52 serum samples) (naturally infected); G2 - non-vaccinated animals (28 serum samples) positive in RBT (Rose Bengal test) and 2ME (2-mercaptoethanol test) selected from brucellosis-positive herds; G3 - animals from a brucellosis-free area (32 serum samples); G4 - S19 vaccinated heifers (114 serum samples); G5 – RB51 vaccinated heifers (60 serum samples); G6 - animals inoculated with inactivated Yersinia enterocolitica O:9 (42 serum samples). Diagnostic sensitivity (DSe) and diagnostic specificity (DSp) were estimated using the frequentist approach and the confidence interval (CI) (95%) calculated by the Clopper-Pearson (exact) method. The DSe for iELISA_MDH in the G1 group was 71.7% (CI 95%: 57.6–83.2%) and for the G2 100.0% (CI 95%: 87.7–100.0%), whereas the DSp was 84.4% in the G3 (CI 95%: 67.2–94.7%). For the iELISA_SOD the DSe was estimated 67.3% for the G1 (CI 95%: 52.9–79.7%) and 71.4% for G2 (CI 95%: 51.3–86.8%), while the DSp for G3 was 87.5% (CI 95%: 71.0–96.5%). iELISA_MDH and iELISA_SOD showed potential to be used in the diagnosis of infected animals, increasing the range of serological tests available for the diagnosis of bovine brucellosis, with the advantage of being S-LPS-free. However, none of the tests could differentiate between infection and vaccination. •iELISA_MDH and SOD showed potential to be used in the diagnosis of infected animals.•iELISA_MDH and SOD expand the range of LPS-free serological tests for bovine brucellosis.•None of the tested iELISA could differentiate between infection and vaccination.