Investigation of antibiotic susceptibilities of Brucella Strains isolated from various clinical samples in eastern Turkey

Background: Brucellosis is a worldwide zoonotic disease that causes serious public health problems. This study aimed to identify Brucella strains isolated from various clinical samples by conventional and molecular methods and to determine antimicrobial susceptibilities against doxycycline (DOX), streptomycin (STR), ciprofloxacin (CIP) and rifampicin (RIF) by the gradient strip (E test) test method. Methods: A total of 87 Brucella strains isolated from various clinical specimens between 2004 and 2018 were included in this study. While four of the 87 strains included in the study were identified only at the genus level, the remaining 83 strains were identified at the species level by the Real-Time Multiplex PCR (M-RT-PCR) method and conventional methods were used for biotyping. Results: According to molecular identification results, 83 strains were identified as B. melitensis by the M-RT-PCR method, with 82 strains identified as Brucella melitensis biovar (bv) 3 and one as B. melitensis bv 1 according to the conventional biotyping method. Among the antibiotics studied, CIP was found to be the most active agent according to the minimum inhibitory concentrations (MIC)90 values. This was followed by DOX and STR, respectively. While all of the isolates were sensitive to CIP, DOX and STR, 18 (20.7%) strains were found to be moderately susceptible to RIF, with the highest values of MIC50 and MIC90. Conclusions: In our study, all strains were identified as B. melitensis. DOX, STR, CIP and RIF used in the treatment of brucellosis were found to be effective. © 2021, The Author(s).