Comparative investigation of the presence of Brucella spp. in ram testicles by bacteriological and molecular methods

Brucellosis is a widespread zoonotic disease globally. The disease causes significant economic losses in infected herds, leading to decreased breeding value, infertility, milk losses, and abortions. Moreover, it poses a threat to public health as it can be transmitted to humans in contact with infected animals and animal products. The significance of Brucella agents with zoonotic characteristics for both the environment and public health is substantial. The aim of this study is to conduct a comparative analysis, using bacteriological and molecular methods, of testicular samples from 150 rams of different ages and breeds brought to slaughterhouses in Istanbul. For this purpose, testicular samples from 150 rams brought to slaughterhouses from various cities in the Marmara Region were collected in sterile bags, maintaining the cold chain. These samples were transported to the Brucella Reference Diagnostic Laboratory at the Pendik Veterinary Control Institute (PVKE) for bacteriological and molecular analysis. From the collected samples, Brucella spp. was isolated from only one ram's testicular sample (0.67%). Phenotypic tests identified the isolate as B. melitensis biotype 3. In the Real-Time PCR assay, DNA samples obtained after extraction using a commercial extraction kit were tested with specific primers and probes for B. melitensis, B. ovis, B. melitensis Rev1, and B. abortus species. The sample identified as B. melitensis biotype 3 through culture was also confirmed as B. melitensis in Real-Time PCR. This study revealed both phenotypic and genotypic positivity in the same testicular sample. Selected from the Marmara Region, it was determined that the brucellosis positivity rate in the animal study group is 0.67% . In conclusion, the data suggest that B. melitensis remains a dominant species in small ruminants, and both methods can be used for pathogen identification in future epidemiological studies. However, considering the faster turnaround and higher diagnostic power of Real-Time PCR compared to culture, it is deemed advantageous for future control and eradication efforts. Given the substantial economic losses caused by infection in our country, the continuation of national strategic plans is deemed necessary. This research will contribute to national and international literature and guide researchers in future comprehensive studies.