Acinetobacter dijkshoorniae sp. nov., a new member of the Acinetobacter calcoaceticus-Acinetobacter baumannii complex mainly recovered from clinical samples in different countries

The recent advances in bacterial species identification methods have led to the rapid taxonomic diversification of the genus Acinetobacter. In the present study, phenotypic and molecular methods have been used to determine the taxonomic position of a group of 12 genotypically distinct strains belonging to the Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex, initially described by Gerner-Smidt and Tjernberg in 1993, that are closely related to A. pittii. Strains characterized in this study originated mostly from human samples obtained in different countries over a period of 15 years. rpoB and MLST sequences were compared against those of 94 strains representing all species included in the ACB complex. Cluster analysis based on such sequences showed that all 12 strains grouped together in a distinct clade closest to A. pittii that was supported by bootstrap values of 99%. Values of average nucleotide identity based on BLAST between the genome sequence of strain JVAP01 (NCBI accession n masculine. LJPG00000000) and those of other species from the ACB were always < 91.2%, supporting the species status of the group. In addition, the metabolic characteristics of the group matched those of the ACB complex and the analysis of their protein signatures by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry identified some specific peaks. Our results support the designation of these strains as a novel species and we propose the name A. dijkshoorniae sp. nov. The type strain is JVAP01T (CECT 9134T, LMG 29605T)