Molecular survey of BCSP31 and IS711 using PCR assays in detection of Brucella spp. in raw milk

Abstract

Brucella spp. as animal pathogens causes human brucellosis, the most momentous zoonotic diseases all over the world that result in economic pressure, human morbidity, and poverty. Brucellosis is commonly transmitted by infected dairy products. The prevalence of Brucella spp. and high consumption of unpasteurized dairy products in urban areas of Iran imposes further studies to clarify the prevalence of Brucella species. This molecular survey was purposefully designed to determine the prevalence of Brucella in raw milk collected from milk sellers using PCR in Zanjan province, Iran. In this molecular cross-sectional study, 73 raw milk samples with a volume of 40 ml gathered (6 samples from sheep and 67 samples from bovine) from raw milk vendors in Zanjan province. DNA of bacteria was extracted from the raw milk samples using (GeneALL, South Korea) kit according to the manufacturer protocol. Specific primers (B4 and B5) were used to the amplification of BCSP31 gene. Five primers (Ba-sp, Bm-sp, Bo-sp, Bs-sp, and IS711-sp) were used to detect Brucella spp. (Brucella abortus, Brucella melitens, Brucella ovis, and Brucella suis) among the positive samples for bcsp31 gene. From the 73 raw milk samples collected, 38 cases (52%) were positive for Brucella genus, 3 cases (7.8%) belonged to Brucella abortus and 2 cases (5.2%) belonged to Brucella melitensis. There were no positive cases for both Brucella ovis and Brucella suis. Results of this study proved that the prevalence of Brucella in raw milk is still a threat to public health, which should have a deeper look at the control strategies and methods of the prevention of brucellosis in the livestock.