cRapid and effective diagnosis of brucellosis is a challenge for clinicians. Even when diagnosis is on time and therapy is initiated, meticulous follow-up appointments are crucial for ensuring the efficacy of the treatment. Due to shortcomings of serological methods, molecular diagnosis, especially real-time PCR, is becoming a main approach in laboratory diagnostics. Thus, the development of efficient procedures and standardization of the PCR tests will have a great impact on the precise detection and quantification of bacterial DNA loads, which is valuable for the medical management of brucellosis patients. We developed a new TaqMan real-time PCR directed to bcsp31, a shared gene of the brucellae. The bcsp31 gene fragment was cloned into pJET1.2. Recombinant pJET1.2-bcsp31 was linearized by HindIII digestion, and the product was used for the preparation of a standard curve. A panel of Brucella spp. and non-Brucella pathogens was tested. No bacterial genomes other than those of the brucellae were detected. According to the results, specificity of the method was 100%. In a clinical assessment, the positive-control group comprised 37 patients with microbiologically confirmed brucellosis, and 25 healthy individuals served as the negative-control group. By the end of the treatment period, there was a significant decrease in the DNA load of the 37 brucellosis patients, which persisted for the 4 weeks of monitoring after treatment, suggesting that our proposed method is an efficient monitoring tool. Serum samples prior to any treatment were collected from the 25 serologically suspicious patients and assessed by our method; 72% of these patients tested positive for brucellosis.T he brucellae are facultative, intracellular, Gram-negative bacteria that infect animals and humans (1). Although it has been eradicated in some developed countries, brucellosis still remains a major problem worldwide. Diagnosis of the disease presents a major challenge to clinical and veterinary services (2, 3). Brucella spp. are able to survive within host cells, leading to relapses and focal complications (1). Early diagnosis of brucellosis results in early initiation of therapy, which plays a key role in the success of the control and eradication programs; nonetheless, accurate diagnosis requires reliable and sensitive diagnostic tools (4). The intracellular localization of the bacteria and the slow evolution of the disease hamper the usefulness of blood cultures (5). Despite being the gold standard, isolation of brucellae from blood culture or other sterile body fluids has a sensitivity of about 70% (4, 6). Serodiagnostic assays are principally based on antibodies against the Brucella lipopolysaccharide (LPS) and have high sensitivity but low specificity. The low specificity may be due to the crossreaction of antibodies with LPS from other bacterial species and subsensitive or high-immunity reactions, depending on the subclinical or endemic prevalence of the disease (4, 6, 7). The presence of IgG and IgM for months after therapy complicates...
