title: In vitro activities and detection performances of cefmetazole and flomoxef for extended-spectrum β-lactamase and plasmid-mediated AmpC β-lactamase-producing Enterobacteriaceae.
abstract: To investigate the in vitro activities of cephamycins (cefmetazole and flomoxef) for extended-spectrum β-lactamase (ESBL)- and plasmid-mediated AmpC β-lactamase (pAmpC)-producing Enterobacteriaceae, a total of 574 third-generation cephalosporin-resistant clinical isolates were collected at a Japanese multicenter study. PCR and sequencing identified 394 isolates with only ESBL genes, 63 isolates with only pAmpC genes, and 6 isolates with both ESBL and pAmpC genes. blaCTX-M types predominated 95.5% of the ESBL genes, and blaCMY-2 predominated 91.3% of the pAmpC genes. The MIC50/90 values of cefmetazole and flomoxef were ≤ 1/4 and ≤ 1/≤ 1 μg/mL for isolates with only ESBL genes, respectively, and 16/>16 and 8/16 μg/mL for isolates with only pAmpC genes, respectively. Flomoxef ≥ 4 μg/mL had the best screening performance for the detection of isolates with pAmpC genes. Flomoxef had better in vitro activities against ESBL-producing Enterobacteriaceae and provided a clearer distinction between ESBL and pAmpC-producing Enterobacteriaceae compared to cefmetazole.
authors.affiliation: Department of Clinical Laboratory Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: yazblood@kuhp.kyoto-u.ac.jp.
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Matsumura
authors.affiliation: Department of Clinical Laboratory Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: masakiy@kuhp.kyoto-u.ac.jp.
authors.forename: Masaki
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Clinical Laboratory Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: mnagao@kuhp.kyoto-u.ac.jp.
authors.forename: Miki
authors.initials: M
authors.lastname: Nagao
authors.affiliation: Department of Clinical Laboratory Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: mbac@kuhp.kyoto-u.ac.jp.
authors.forename: Michio
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Department of Clinical Laboratory Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: stakakr@kuhp.kyoto-u.ac.jp.
authors.forename: Shunji
authors.initials: S
authors.lastname: Takakura
authors.affiliation: Department of Clinical Laboratory Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: sichiyam@kuhp.kyoto-u.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ichiyama
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015311:Cefmetazole / Q000494:pharmacology*; D002511:Cephalosporins / Q000494:pharmacology*; D004755:Enterobacteriaceae / Q000145:classification / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics; D004756:Enterobacteriaceae Infections / Q000382:microbiology; D005838:Genotype; D006801:Humans; D007564:Japan; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D015311:Cefmetazole; D001618:beta-Lactamases; C045693:flomoxef
keywords: AmpC; Cephamycin; ESBLs; Genotype; MIC