Bacteriological and molecular investigation of B. melitensis in dairy cows in Iran

Abstract

It is extremely important to investigate the presence of Brucella melitensis as a nonspecific and heterogeneous agent in dairy cows in Iran due to mixed populations of sheep, goats, and cattle. B. melitensis from infected sheep or goat herds may be introduced into the cattle population in this area. Hence, it is essential to obtain epidemiological data on the probable existence of B. melitensis as a different source of the infection or new exotic Brucella phenotypes development in dairy cow herds in Iran. The purpose of this study was to investigate the presence of B. melitensis infection in cows, using both traditional bacteriological tests and polymerase chain reaction (PCR)-based assay. Traditional biotyping and PCR results of 42 Brucella spp. isolates from Tehran and Fars (northern and southern) provinces of Iran identified five (11.9%) and 37 (88.1%) as B. melitensis (four biovar 1 and one biovar 2) and 37 (88.1%) Brucella abortus biovar 3. This study demonstrated that B. melitensis infection in dairy cows of Iran is still present at a low level. However, the Iranian Veterinary Organization should be careful to have dairy cow herds free of B. melitensis infection as a nonspecific agent of brucellosis, since this type of brucellosis may be extended and act as a potential source of severe infection in humans.