title: Development of a novel chromogenic method, Penta-well test, for rapid prediction of β-lactamase classes produced in clinical Enterobacteriaceae isolates.
abstract: We developed a novel chromogenic method, Penta-well test, which enables the rapid detection and classification of β-lactamases in clinical Enterobacteriaceae isolates. This test is based on a combination of nitrocefin and 3 β-lactamase inhibitors specific to classes A, B, and/or C, with nitrocefin hydrolysis by β-lactamases being assessed by optical density measurements at 490 nm. When the cutoff value for each β-lactamase class was determined (0.09, 0.4, and 0.55 for class A, class B, and class C β-lactamase producers, respectively), the sensitivity and specificity of classification were 93.5% and 68.8% for class A, 93.8% and 100% for class B, and 86.7% and 100% for class C, respectively. Moreover, this method allowed accurate β-lactamase classification in 20 of 23 (87.0%) isolates producing plural class of β-lactamases. Thus, the Penta-well test can provide information that would be useful in the accurate detection and classification of β-lactamases produced by causative bacteria.
authors.affiliation: Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20, Daikominami, Higashi-ku, Nagoya, Aichi, 461-8673, Japan. Electronic address: mura.tatsuki@h.mbox.nagoya-u.ac.jp.
authors.forename: Tatsuki
authors.initials: T
authors.lastname: Mura
authors.affiliation: Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20, Daikominami, Higashi-ku, Nagoya, Aichi, 461-8673, Japan. Electronic address: kumiko@met.nagoya-u.ac.jp.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Kawamura
authors.affiliation: Department of Bacteriology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan. Electronic address: wachino@med.nagoya-u.ac.jp.
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Wachino
authors.affiliation: Department of Bacteriology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan. Electronic address: keigo@niid.go.jp.
authors.forename: Keigo
authors.initials: K
authors.lastname: Shibayama
authors.affiliation: Department of Bacteriology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan; Department of Bacteriology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan. Electronic address: yarakawa@med.nagoya-u.ac.jp.
authors.forename: Yoshichika
authors.initials: Y
authors.lastname: Arakawa
mesh_terms: D001431:Bacteriological Techniques / Q000379:methods*; D002511:Cephalosporins / Q000378:metabolism; D002863:Chromogenic Compounds / Q000378:metabolism; D004755:Enterobacteriaceae / Q000201:enzymology* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000382:microbiology*; D006801:Humans; D006868:Hydrolysis; D012680:Sensitivity and Specificity; D013997:Time Factors; D001618:beta-Lactamases / Q000032:analysis* / Q000145:classification*
chemical_list: D002511:Cephalosporins; D002863:Chromogenic Compounds; D001618:beta-Lactamases; C021720:nitrocefin
keywords: Chromogenic method; Classify; Enterobacteriaceae; Penta-well test; β-Lactamase