Comparative evaluation of nested PCR for diagnosis of human brucellosis

Abstract Objectives: Brucellosis is a worldwide zoonotic disease with high morbidity in the absence of treatment. The early diagnosis of brucellosis is efficient to prevent chronic infections. The aim of this study is evaluation of nested PCR efficiency in comparison with conventional methods for diagnosis of human brucellosis. A total of 120 patients with brucellosis symptoms were included in this study. Serological and microbiological tests and nested PCR were used for detection of Brucella bacteria. Results: Based on serological tests, 60.83% (73/120) of individuals were positive for brucellosis which only 8.33% of cases were confirmed by blood culture. Among them, 55% of cases were positive in serum agglutination test (SAT≥1:160) and Coombs (C-SAT≥1:160) tests. Furthermore, 7 negative SAT cases were positive in C-SAT as evidence for chronic brucellosis. Also, 68.18% and 56.06% of SAT positive samples were positive in blood nested PCR and serum nested PCR respectively. The sensitivity of blood nested PCR was more than serum nested PCR, SAT≥1:160 and blood culture (P<0.001). The specificity of the blood and serum nested PCR was 100% compared with blood culture and SAT≥ 1:160. Our findings highlight high performance of nested PCR for diagnosis of both acute and chronic brucellosis.