Epidemiological survey of rifampicin resistance in clinic isolates of Brucella melitensis obtained from all regions of Turkey.

The aim of the present study was to assess the antimicrobial susceptibility of Brucella melitensis isolates to rifampicin (RIF) depending on time and regional differences. A total of 94 human Brucella isolates collected in an 8-year period from the beginning of 2002 to the end of 2009 throughout Turkey were investigated. The isolates were identified at species and biovar levels by conventional methods, and minimum inhibitory concentrations (MIC) of RIF was determined by using the E test method. All isolates were identified as B. melitensis (93 isolates, biovar 3; 1, biovar 1), and MIC(50) and MIC(90) values of RIF were 1 and 1.5 μg/ml, respectively (MIC range, 0.25-1.5 μg/ml). All isolates were sensitive to RIF except 2 isolates, which had intermediate susceptibility to RIF. These findings indicated that B. melitensis biovar 3 may be the most frequently agent responsible for human brucellosis in Turkey. None of the isolates in our region was resistant to RIF.