[Comparison of conventional methods and real-time multiplex polymerase chain reaction for identification and typing of Brucella isolates of human origin].

Brucellosis which is a worldwide zoonotic disease, still constitutes a major public health problem in rural areas of Turkey. The aim of the present study was to evaluate the species and biovar distribution of 187 presumptive Brucella strains isolated from patients inhabiting at the provinces in Eastern, South Eastern and Mediterranean regions over a 7-years period (from 2001 to 2007) and to compare multiplex real-time-polymerase chain reaction (M-RT-PCR) and conventional biotyping for the differentiation of three Brucella species. The isolates were identified at genus level by conventional microbiological methods and classified using the classical Brucella species biotyping scheme based on CO2 requirement for growth, urease activity, H2S production, sensitivity to basic fuchsin and thionin (20 and 40 µg/ml), lysis by Tbilisi and Berkeley phages, and agglutination with monospecific antisera for A and M antigens. All Brucella isolates were identified as Brucella melitensis biovar 3. M-RT-PCR assay targeted bcsp31 gene and the specific integration of IS711 elements within the genome of the respective Brucella species. For the identification of Brucella spp. The primers and probes which targeted the bcsp31 gene were used. The Brucella abortus primers and probe set targeted the specific insertion of an IS711 element downstream of the alkB gene, whereas the B.melitensis primers and probe set targeted the insertion of an IS711 element downstream of BMEI1162. M-RT-PCR results were found to be 100% compatible with the reference conventional typing methods. Due to its high sensitivity, the M-RT-PCR assay could be a valuable tool for the rapid detection and differentiation of Brucella species in clinical samples which usually have very low bacterial load. These findings indicated that B.melitensis biovar 3 was by far the most frequent species for human brucellosis in these specific regions of Turkey and multiplex-RT-PCR seemed to be promising in the detection and differentiation of Brucella species.