Genotypes and antimicrobial susceptibility of Rhizobium radiobacter isolated from pediatric patients with bacteremia

Abstract:

ObjectiveTo investigate genotypes and antimicrobial susceptibility of Rhizobium radiobacter (R. radiobacter) isolated from pediatric patients with bacteremia.MethodsR. radiobacter strains from blood cultures of pediatric patients with bacteremia from February 2013 through February 2014 were collected. 16S rDNA fragment was amplified by polymerase chain reaction(PCR), bacterial genotypes were identified by pulsedfield gel electrophoresis (PFGE), antimicrobial susceptibility testing were performed by KirbyBauer disk diffusion method. Results13 isolates of R.radiobacter were isolated from 12 children with positive blood culture, which including 3 genotypes, the homology of 16S rDNA fragment and R.radiobacter IFM 10623 was up to 99%. According to CLSI 2003 standard, these 13 R.radiobacter were resistant to ceftazidime, piperacillin, ticarcillin, piperacillin / tazobactam, ticarcillin / clavulanic acid, aztreonam and polymyxin B, but sensitive to cefepime, doripenem, imipenem, meropenem, tobramycin,  netilmicin, ciprofloxacin, levofloxacin, and norfloxacin.  In addition, cefotaxime and ceftriaxone showed larger inhibition zone.ConclusionTherapy of R.radiobacter infection should be based on antimicrobial susceptibility testing results;  cefotaxime and ceftriaxone are better selection for the therapy of R.radiobacter infection in pediatric patients.