Characterization of 'Pseudomonas azelaica' DSM 9128, leading to emended descriptions of Pseudomonas citronellolis Seubert 1960 (Approved Lists 1980) and Pseudomonas nitroreducens Iizuka and Komagata 1964 (Approved Lists 1980), including Pseudomonas multiresinivorans as its later heterotypic synonym.

Polyphasic characterization of strain DSM 9128, described as 'Pseudomonas azelaica' by Janota-Bassalik et al. [Acta Microbiol Pol B 3, 143-153 (1971)], and four biochemically similar isolates was performed with the aim of validly publishing the name 'Pseudomonas azelaica'. Based on 16S rRNA gene sequence analysis, DNA-DNA hybridization, fatty acid patterns and extensive biochemical testing, it was concluded that DSM 9128, two further strains and the type strains of Pseudomonas nitroreducens and Pseudomonas multiresinivorans form a highly related cluster. However, DNA-DNA binding did not conclusively resolve whether these strains should be regarded as members of one species. Based on results gained with the above-mentioned methods, two other isolates were assigned to the species Pseudomonas citronellolis, a species very close to P. nitroreducens. Based on genetic and biochemical similarities, it is suggested that Pseudomonas multiresinivorans should be considered as a later heterotypic synonym of Pseudomonas nitroreducens. The species descriptions of P. nitroreducens and P. citronellolis are emended.