Tomohiko Tamura: Biological Resource Center, National Institute of Technology and Evaluation (NBRC), 2-5-8 Kazusakamatari, Kisarazu, Chiba, 292-0818, Japan. tamura-tomohiko@nite.go.jp. ORCID
Shoko Ohji: Biological Resource Center, National Institute of Technology and Evaluation (NBRC), 2-49-10 Nishihara, Shibuya-ku, Tokyo, 151-0066, Japan.
Natsuko Ichikawa: Biological Resource Center, National Institute of Technology and Evaluation (NBRC), 2-49-10 Nishihara, Shibuya-ku, Tokyo, 151-0066, Japan.
Akira Hosoyama: Biological Resource Center, National Institute of Technology and Evaluation (NBRC), 2-49-10 Nishihara, Shibuya-ku, Tokyo, 151-0066, Japan.
Atsushi Yamazoe: Biological Resource Center, National Institute of Technology and Evaluation (NBRC), 2-5-8 Kazusakamatari, Kisarazu, Chiba, 292-0818, Japan.
Moriyuki Hamada: Biological Resource Center, National Institute of Technology and Evaluation (NBRC), 2-5-8 Kazusakamatari, Kisarazu, Chiba, 292-0818, Japan. ORCID
Hisayuki Komaki: Biological Resource Center, National Institute of Technology and Evaluation (NBRC), 2-5-8 Kazusakamatari, Kisarazu, Chiba, 292-0818, Japan.
Chiyo Shibata: Biological Resource Center, National Institute of Technology and Evaluation (NBRC), 2-5-8 Kazusakamatari, Kisarazu, Chiba, 292-0818, Japan.
Tetsuhiro Matsuzawa: Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, Chiba, 260-8673, Japan.
Tohru Gonoi: Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, Chiba, 260-8673, Japan.
Ken-Ichiro Suzuki: Biological Resource Center, National Institute of Technology and Evaluation (NBRC), 2-5-8 Kazusakamatari, Kisarazu, Chiba, 292-0818, Japan.
Nobuyuki Fujita: Biological Resource Center, National Institute of Technology and Evaluation (NBRC), 2-49-10 Nishihara, Shibuya-ku, Tokyo, 151-0066, Japan.
Type strains of 72 validated Nocardia species were phylogenetically analyzed based on the multilocus sequence analysis (MLSA) concatenated atpD-groL1-groL2-recA-rpoA-secY-sodA-ychF. Furthermore, their similarity based on digital DNA-DNA hybridization (dDDH) was calculated. Nocardia soli, Nocardia cummidelens and Nocardia salmonicida, Nocardia nova and Nocardia elegans, Nocardia exalbida and Nocardia gamkensis, and Nocardia coubleae and Nocardia ignorata formed coherent clades, respectively. Moreover, each set showed over 70% relatedness by dDDH and shared common phenotypic characteristics. Therefore, we propose a reclassification of Nocardia soli and Nocardia cummidelens as a later heterotypic synonym of Nocardia salmonicida, Nocardia elegans as a later heterotypic synonym of Nocardia nova, Nocardia gamkensis as a later heterotypic synonym of Nocardia exalbida, and Nocardia coubleae as a later heterotypic synonym of Nocardia ignorata.
