Evaluation of Diagnostic Techniques for the Detection of Brucella spp in Camel Sera and In-Vitro Testing Their Susceptibility against Antimicrobial Agents

摘要

Brucellosis is a zoonotic disease and represents one of the most common public health problems worldwide. For diagnosis and treatment of the disease, sensitive and accurate methods are required. Although serological techniques are considered the main diagnostic method of camel brucellosis, these tests have been immediately transferred from cattle without sufficient legalization. Until now, scanty data on utilization of real-time PCR for identification of Brucella in camel is available. Therefore, this study was conducted to evaluate the serological techniques and real-time PCR for the detection of Brucella species and to determine in vitro antimicrobial resistance of these strains to frequently used anti-Brucella agents. A total of 410 serum samples were identified genotypically by real-time PCR and serologically by Rose Bengal Plate Test (RBPT), Slow Agglutination Test (SAT), Complement Fixation Test (CFT), competitive enzyme-linked immunosorbent assays (cELISA) and fluorescence polarization assay (FPA). In vitro activities of various antimicrobials were also evaluated by the E test method. According to the serological results, FPA demonstrated the maximum number of positive cases (84.87%) followed by CFT (79.75%), SAT (77.56%), RBPT (76.58%) and cELISA (75.36%). However, 88.53% of all cases were identified by real-time PCR. The lowest MIC_(90) values were observed in trimethoprim-sulfamethoxazole (0.195 μg/ml), doxycycline (0.390 μg/ml), chloramphenicol (0.781 μg/ml) and amikacin (1.562 μg/ml). In contrast, amoxicillin/clavulanic acid, streptomycin, rifampin, ceftazidime, cefotriaxone and ceftriaxone had high MIC_(50) and MIC_(90) against most of identified Brucella strains. Based on the results of this study, it is recommended to use a real-time PCR technique in combination with at least one serological test for precise diagnosis of camel brucellosis in developed and less-developed countries. In addition, using a combination of rifampin, doxycycline with trimethoprim-sulfamethoxazole is considered promising anti-Brucella agents. Camels must be included in nationwide plans for eradication and control of brucellosis in endemic regions.