Toru Kanahashi1, Yasufumi Matsumura2, Masaki Yamamoto3, Michio Tanaka4, Miki Nagao5. 1. Department of Clinical Laboratory and Department of Infection Control and Prevention, Kyoto University Hospital, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan. Electronic address: kanahashi.toru.7e@kyoto-u.ac.jp. 2. Department of Clinical Laboratory and Department of Infection Control and Prevention, Kyoto University Hospital, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan; Department of Clinical Laboratory Medicine, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan. Electronic address: yazblood@kuhp.kyoto-u.ac.jp. 3. Department of Clinical Laboratory and Department of Infection Control and Prevention, Kyoto University Hospital, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan; Department of Clinical Laboratory Medicine, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan. Electronic address: masakiy@kuhp.kyoto-u.ac.jp. 4. Department of Clinical Laboratory Medicine, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan. Electronic address: mbac@kuhp.kyoto-u.ac.jp. 5. Department of Clinical Laboratory and Department of Infection Control and Prevention, Kyoto University Hospital, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan; Department of Clinical Laboratory Medicine, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan. Electronic address: mnagao@kuhp.kyoto-u.ac.jp.
Abstract
INTRODUCTION: The real-time PCR assay Xpert Carba-R and the lateral flow immunoassay NG-Test CARBA5 were developed to detect 5 types of carbapenemase genes (blaIMP, blaKPC, blaVIM, blaOXA-48, and blaNDM). METHODS: We compared the diagnostic performance, turn-around time, and cost of these assays. Carbapenemase genes were defined using the Carba NP test, modified Carbapenem Inactivation Methods (mCIM), multiplex PCR, and whole-genome sequencing. We included clinical Enterobacterales isolates (n = 36) and nonfermenting gram-negative bacilli isolates (n = 17) collected from 16 acute-care hospitals in the Kinki region of Japan. RESULTS: Twenty-six of these 53 isolates were positive according to both of the Carba NP test and mCIM and, contained the following carbapenemase genes: blaIMP-1 (n = 3), blaIMP-6 (n = 1), blaIMP-19 (n = 12), blaIMP-26 (n = 1), blaIMP-41 (n = 2), blaIMP-66 (n = 2), blaNDM-1 (n = 3), and blaVIM-2 (n = 2). All of the remaining 27 isolates were negative according to the Carba NP test, mCIM, and multiplex PCR. The specificities of both assays were 100%. The sensitivity of the Xpert Carba-R assay was as low as 53.8% and that of the NG-Test CARBA5 was 92.3% because the former failed to detect all isolates with blaIMP-19 (n = 12) and the latter failed to detect isolates with blaIMP-66 (n = 2). Both assays can easily be performed in less than 5 min. CONCLUSIONS: The NG-Test CARBA5 assay was superior with regard to assay time and cost per sample. We propose the use of the NG-Test CARBA5 assay in clinical laboratories where IMP-type carbapenemases are endemic.
INTRODUCTION: The real-time PCR assay Xpert Carba-R and the lateral flow immunoassay NG-Test CARBA5 were developed to detect 5 types of carbapenemase genes (blaIMP, blaKPC, blaVIM, blaOXA-48, and blaNDM). METHODS: We compared the diagnostic performance, turn-around time, and cost of these assays. Carbapenemase genes were defined using the Carba NP test, modified Carbapenem Inactivation Methods (mCIM), multiplex PCR, and whole-genome sequencing. We included clinical Enterobacterales isolates (n = 36) and nonfermenting gram-negative bacilli isolates (n = 17) collected from 16 acute-care hospitals in the Kinki region of Japan. RESULTS: Twenty-six of these 53 isolates were positive according to both of the Carba NP test and mCIM and, contained the following carbapenemase genes: blaIMP-1 (n = 3), blaIMP-6 (n = 1), blaIMP-19 (n = 12), blaIMP-26 (n = 1), blaIMP-41 (n = 2), blaIMP-66 (n = 2), blaNDM-1 (n = 3), and blaVIM-2 (n = 2). All of the remaining 27 isolates were negative according to the Carba NP test, mCIM, and multiplex PCR. The specificities of both assays were 100%. The sensitivity of the Xpert Carba-R assay was as low as 53.8% and that of the NG-Test CARBA5 was 92.3% because the former failed to detect all isolates with blaIMP-19 (n = 12) and the latter failed to detect isolates with blaIMP-66 (n = 2). Both assays can easily be performed in less than 5 min. CONCLUSIONS: The NG-Test CARBA5 assay was superior with regard to assay time and cost per sample. We propose the use of the NG-Test CARBA5 assay in clinical laboratories where IMP-type carbapenemases are endemic.
Authors: Fang Wang; Lei Wang; Huimin Chen; Na Li; Yan Wang; Yan Li; Wei Liang Journal: Front Cell Infect Microbiol Date: 2021-12-02 Impact factor: 5.293