L Rahbarnia - Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
S Farajnia - Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
B Naghili - Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
N Saeedi - Research Center for Pharmaceutical Nanotechnology, Research and Development Complex, Tabriz University of Medical Sciences, Tabriz, Iran

Brucellosis is recognized as a zoonotic disease with high morbidity in the absence of treatment. The primary diagnosis of brucellosis can be effective in the achievement of satisfying treatment results and prevention of chronic infections. The present study aimed to compare the efficiency of conventional microbiological and serological approaches with nested Polymerase chain reaction (nested PCR) for rapid diagnosis of human brucellosis. A total of ۱۲۰ subjects with symptoms of brucellosis were included in the study. The sensitivity and specificity of nested PCR for the detection of Brucella bacteria were compared with serological and blood culture methods. Out of ۱۲۰ patients enrolled, brucellosis was detected in ۷۳ (۶۰.۸۳%) cases based on serological tests with a blood culture confirmation in ۸.۳۳% of participants. Based on the obtained results, ۵۵% of cases were positive in serum agglutination test (SAT≥۱:۱۶۰), and Coombs (C-SAT≥۱:۱۶۰) tests. Furthermore, seven negative SAT cases were positive in C-SAT as evidence of chronic brucellosis. The results of the ۲-mercaptoethanol (۲-ME) ≥ ۱:۸۰ test were negative in six SAT-positive cases. Based on nested PCR results, ۶۸.۱۸% and ۵۶.۰۶% SAT positive samples were also detected by blood nested PCR and serum nested PCR, respectively. The sensitivity of blood nested PCR was significantly more than serum nested PCR, SAT≥۱:۱۶۰, and blood culture (p <۰.۰۰۱). Moreover, the specificity of blood and serum nested PCR was obtained at ۱۰۰%, compared to blood culture and SAT≥ ۱:۱۶۰. In the present study, the nested PCR was able to identify chronic brucellosis in SAT negative patients. As evidenced by the obtained results, the nested PCR showed higher efficiency for rapid diagnosis of human brucellosis, as compared to the blood culture method. Furthermore, the findings pointed to the high performance of nested PCR for rapid diagnosis of both chronic and acute brucellosis.

Brucellosis, C-SAT, ۲ME, Nested PCR, SAT