The first report of isolation and molecular characterisation of Brucella melitensis Rev-1 vaccine strain from an aborted sheep fetus in Turkey

The aim of this study was to evaluate a RAPD-PCR for the detection of B. melitensis Rev-1 vaccine strain. In addition, our objective was to isolate, identify and genetically characterize B. melitensis strains from aborted sheep fetuses by PCR, RAPD-PCR and PCR-RFLP methods. A total of 86 aborted sheep fetuses obtained from different herds (n = 86) in lambing season of 2007–2008 were evaluated. Twelve B. melitensis strains, which isolated from aborted sheep fetuses (n = 12) from same region between 2006 and 2007 years were also added in this study for biotyping. Brucella strains were isolated from 24 (28%) out of 86 aborted sheep fetus samples. All Brucella strains were identified as B. melitensis by biochemical tests and PCR. Of the 36 B. melitensis isolates, 3, 32 and 1 were identified as biotype 1, biotype 3 and B. melitensis Rev-1 vaccine strain, respectively. Field isolated B. melitensis Rev-1 vaccine strain was confirmed by PCR-RFLP. Nine of 36 B. melitensis isolates were detected for being atypical since they were susceptible to penicillin or thionin and basic fuchsin. DNA fingerprints of field isolates and B. melitensis Rev-1 vaccine strain were obtained by RAPD-PCR method and dendograms were created by UPGMA and NJ. Strains were separated similarly 14 subgroups in both dendograms. 36 B. melitensis isolates from Konya region were detected that they had not from the same source. Atypical strains that located in different subgroups have different clonal origins. Levels of genetic similarity between reference strains and field isolates were 50.0–99.9%. That was 88.9% between reference vaccine strain B. melitensis Rev-1 and field isolated B. melitensis Rev-1. It was also detected that B. melitensis Rev-1 vaccine strain cannot be identified by the method RAPD-PCR alone, while isolates in located the same main group with B. melitensis Rev-1 can be suspected for being the vaccine strain. In conclusion, B. melitensis strains isolated in Konya region were found to be from different sources by RAPD-PCR. B. melitensis biotype 3 was the most common biotype. B. melitensis Rev-1 vaccine strain was isolated from aborted fetus in Turkey for the first time. PCR-RFLP appear valuable tool for epidemiological studies on B. melitensis Rev-1 vaccine strain. RAPD-PCR method was concluded as for being an easy to use and interpretate. This is recommended for future studies on epidemiology of Brucellosis.