Serodiagnosis of human brucellosis by an indirect ELISA test using recombinant outer membrane protein 19 kDa (rOMP19) as an antigen

Abstract

Background Brucellosis remains one of the global health concerns that reemerges in recent years. Delayed or inaccurate diagnosis end to a long treatment duration and financial burden; therefore, finding a good antigen for detection of specific anti-Brucella antibodies is crucial. We intended to evaluate the serodiagnosis value of recombinant Brucella outer membrane protein 19 kDa (rOMP19) using indirect ELISA system compared with Rose Bengal test. Results The OMP19 sequence was successfully cloned into pET-28a and produced in E. coli cells (DE3). After extraction and purification of rOMP19, this protein was used for designing indirect ELISA to detect anti-Brucella antibodies in 73 human sera, including 6 brucellosis-positive and 67 brucellosis-negative samples. The accuracy of rOMP19 ELISA was evaluated by receiver operating characteristic (ROC) curve and then compared with Rose Bengal plate test and a commercial anti-IgG Brucella ELISA kit. In comparison with Rose Bengal plate test, the area under the ROC curve was 0.985 (95% CI, 0.96–1.00). From coordinates of the curve, the optimal cut-off value was selected at 0.147, in which the diagnostic sensitivity was 100%, and the specificity was 94%. At this cut-off point, 10 samples were diagnosed as positive (6 true positives and 4 false positives), while negative samples were all correctly diagnosed. The results of our designed rOMP19 ELISA was the same as data obtained from commercial ELISA kit, which applied LPS as an antigen. Conclusions We concluded that OMP19 is an efficient antigen for the serodiagnosis of human brucellosis.

Brucellosis detection and the role of Brucella spp. cell wall proteins

“…The results were assessed using commercial IgG ELISA kit and RBT. The diagnostic efficiency of ELISA/rOmp16 compared to that of RBT showed high sensitivity (100%) and specificity (95%), and complete agreement between the results of the test and the commercial ELISA kit was observed [41].…”

Isolation and identification of <i>Brucella abortus</i> and <i>B. melitensis</i> in ruminants with a history of abortion: the first report from Eritrea

“…The remaining 35 seropositive animals did not form colonies in Brucella selective media. The detection rate differences observed between the serological test and culture methods could be caused by the cross-reactivity of antibodies against the Brucella lipopolysaccharide virulence factor, which is commonly used for the development of Brucella ELISA kit (Golchin et al, 2023). Gram-negative bacteria such as Escherichia coli O157, Vibrio cholera, and Yersinia enterocolitica have been reported to result in cross-reactivity (Golchin et al, 2022).…”