Comparison of Methods for Diagnosing Brucellosis

Abstract

Objective: To determine the sensitivities of various testing methods for diagnosing brucellosis. Methods: The 267 patients in our cohort were suspected to be infected with Brucella and had been referred to a hospital in Mianeh City, Iran. The mean (SD) age was 37.0 (11.3) years for female patients and 37.1 (13.7) years for male patients. All serum specimens from these patients were examined by the standard agglutination test (SAT), Coombs Wright test, 2-mercaptoethanol (2ME) test, enzyme-linked immunosorbent assay (ELISA) for determining levels of immunoglobulin G (IgG) and immunoglobulin M (IgM), and multiplex polymerase chain reaction (PCR). DNA was extracted. Extracted DNA was checked with human PCR–targeting CRP gene–encoding 485 base pair (bp) as an internal control to ensure that the proper extraction method had been used. Specific primers targeting IS 711 were used for Brucellosis melitensis, B abortus, and B suis. Results: Brucellosis was confirmed in 110 patients (58.2% male and 41.8% female) based on applied diagnostic methods and clinical features. Results of ELISA, the SAT, and PCR were positive in 92, 42, and 51 patients, respectively. B abortus and B melitensis were detected in 16 and 35 patients, respectively. B suis was not detected in any of the specimens. Conclusions: All methods tested in our study need to be used to ensure accurate diagnosis of brucellosis, although ELISA displayed the highest level of efficiency. Also, B melitensis showed a higher frequency rate than B abortus in our cohort.