Pseudoxanthomonas mexicana sp. nov. and Pseudoxanthomonas japonensis sp. nov., isolated from diverse environments, and emended descriptions of the genus Pseudoxanthomonas Finkmann et al. 2000 and of its type species

1 Departamento de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa, Avenida Michoacán y la Purísima s/n, Col. Vicentina, 09340 México DF, Mexico 2 Institut de Recherche pour le Développement (IRD), Cicerón 609, Col. Los Morales, 11530 México DF, Mexico 3 Laboratoire de Microbiologie IRD, IFR-BAIM, Universités de Provence et de la Méditerranée, ESIL case 925, 163 avenue de Luminy, 13288 Marseille cedex 9, France 4 Central Research Laboratories, Ajinomoto Co., Inc., 1-1, Suzuki-Cho, Kawasaki-ku, Kawasaki-shi, 210-8681, Japan 5 Institut für Klinische Mikrobiologie, Immunologie und Hygiene, Wasserturmstr. 3, 91054 Erlangen, Germany 6 LAMIB-CRSBAN, Département de Biochimie-Microbiologie, Unité de Formation et de Recherches en Sciences de la Vie et de la Terre, Université de Ouagadougou, 03 BP 7021, Ouagadougou 03, Burkina Faso 7 Leukaemia Foundation Research Unit, Queensland Institute of Medical Research, 300 Herston Rd, Herston QLD-4000, Australia Correspondence Hervé Macarie herve.macarie{at}esil.univ-mrs.fr Three mesophilic bacteria (strains AMX 26B T , UR374_02 and 12-3 T ) isolated respectively from an anaerobic digester, human urine and urban riverside soil were characterized. Cells were Gram-negative, motile, non-sporulating, straight to curved rods with one polar flagellum and had a strictly respiratory metabolism with O 2 as the preferential terminal electron acceptor. Phylogenetic analysis based on 16S rRNA gene sequences revealed that all strains clustered within the Xanthomonadaceae branch of the Proteobacteria . Isolates AMX 26B T and UR374_02 exhibited 100 % 16S rRNA gene sequence similarity and both were related to strain 12-3 T (99·6 % similarity). The closest relative of all the isolates was Pseudoxanthomonas broegbernensis DSM 12573 T (similarity 97·1–97·5 %), and they were equidistantly related to Xanthomonas species (95·4–96·6 %), Stenotrophomonas species (95·3–96·1 %) and Pseudoxanthomonas taiwanensis ATCC BAA-4040 T (95·3–95·4 %). Chemotaxonomic and biochemical data (branched-chain cellular fatty acid pattern without C 13 : 0 iso 3-OH, ubiquinone with eight isoprenoid units, limited range of substrates used, ability to reduce nitrite but not nitrate with the production of N 2 O) supported their affiliation to the genus Pseudoxanthomonas . The results of DNA–DNA hybridization and/or phenotypic analysis allowed them to be differentiated from the two Pseudoxanthomonas species with validly published names and showed that strain 12-