Molecular Evaluation of Brucella infection in raw milk from the livestock of Famenin city (Famenin Brucellosis cohort study)

BACKGROUND AND OBJECTIVESBrucellosis is one of the most important and well-known zoonosis in the world and especiallyin Iran. A timely and accurate diagnosis of this disease is the starting point of any effectiveprogram to control it in humans and animals. To detect Brucella bacteria in milk and dairyproducts, the rapid agglutination method and milk ring test with Brucella abortus antigen areone of the most important primary screening methods for the presence of Brucella bacteria.Also, the new diagnostic method that has high sensitivity and minimizes the risk oftransmission of infection is polymerase chain reaction (PCR). In this study, we aimed tocompare diagnostic methods for evaluating raw milk samples isolated from domestic animalsin Famenin city of Hamedan province.MATERIALS AND METHODSIn this study, ۷۳۸ raw milk samples from bovine, sheep, and goats in the Famenin regionwere investigated. At first, the primary screening of the presence of Brucella bacteria in milksamples was carried out through the milk ring test using B. abortus antigen. Then, allseropositive samples were selected for molecular evaluation. The DNA from milk sampleswas extracted and utilized in the PCR technique using the BCSP۳۱ target gene and IS۷۱۱locus.RESULTS AND DISCUSSIONOut of ۷۳۸ collected samples, ۴۶ samples were positive in MRT (milk ring test). Among ۴۶seropositive samples, ۴۲ (۹۱.۳%) samples were related to sheep, ۴ (۸.۷%) samples to goats,and no bovine samples had positive results in MRT. ۳۶/۴۶ (۷۸.۲۶%) samples with positiveMRT results were confirmed as Brucella genus using the BCSP۳۱-PCR. Among the ۳۶confirmed samples, ۶/۳۶ (۱۶.۶۶%) samples as B. abortus and ۳۰/۳۶(۸۳.۳۳%) samples as B.melitensis were identified using IS۷۱۱-PCR.CONCLUSIONOur results of the primary serological examination of milk samples of animals did not showcomplete agreement with molecular examinations. This study showed that the PCR methodhas minimal biological contamination and high sensitivity and accuracy, especially indetermining Brucella species.

کلیدواژه ها:

Brucella abortus ، Brucella melitensis ، livestock ، milk ring test ، PCR