title: [Validity of using imipenem as a representative carbapenems and levofloxacin as a representative fluoroquinolones in antibiotics susceptibility test for enterobacteriaceae].
abstract: In antimicrobial susceptibility test for enterobacteriaceae, the efficacies of carpapenems are predicted by the minimum inhibitory concentration (MIC) of imipenem, and that of fluoroquinolones are predicted by the MIC of levofloxacin. To assess its judgement, we compared the MICs of imipenem, meropenem, panipenem, and doripenem for carbapenems, and ciprofloxacin, levofloxacin, tosufloxacin and pazufloxacin for fluoroquinolones of clinically isolated enterobacteria, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Serratia marcescens, Enterobacter cloacae and Citrobacterfreundii, those resistant to the third generation cephalosporin. MIC distributions in low concentration range are estranged in some strains, conspicuously S. marcescens, E. cloacae and C. freundii: meropenem and doripenem displayed low MIC value than imipenem and panipenem. Since the estrangements are appeared MIC value of less than 8 microg/ml, the interpretive results (susceptible, intermediate, resistant) are not affected. In fluoroquinolones, all 4 agents showed almost identical MIC distributions, thus the MIC of levofloxacin is accepted to use the reference for other fluoroquinolones. The existence of the strains harboring carbapenem-resistant gene displaying low MIC value of carbapenems was reported. For the sensitive detection of the candidate of carbapenem-resistant strains, cut-off value of each carbapenem should be reconsidered, and also other phonotype analysis should be applied. Genomic analysis also would be required to detect the carbapenem-resistant gene.
authors: Department of Clinical Pathology, Showa University, School of Medicine.
authors: Nanako
authors: N
authors: Takahashi
authors: Kazuhide
authors: K
authors: Gomi
authors: Fumihiro
authors: F
authors: Yamaguchi
authors: Kunihiko
authors: K
authors: Fukuchi
authors: Rika
authors: R
authors: Wakuta