Taxonomy of haemolytic and/or proteolytic strains of the genus Acinetobacter with the proposal of Acinetobacter courvalinii sp nov (genomic species 14 sensu Bouvet & Jeanjean), Acinetobacter dispersus sp nov (genomic species 17), Acinetobacter modestus sp nov., Acinetobacter proteolyticus sp nov and Acinetobacter vivianii sp nov.

We aimed to define the taxonomic status of 40 haemolytic and/or proteolytic strains of the genus Acinetobacter which were previously classified into five putative species termed as genomic species 14BJ (n=9), genomic species 17 (n=9), taxon 18 (n=7), taxon 19 (n=6) and taxon 20 (n=9). The strains were recovered mostly from human clinical specimens or soil and water ecosystems and were highly diverse in geographical origin and time of isolation. Comparative analysis of the rpoB and gyrB gene sequences of all strains, and the whole-genome sequences of selected strains, showed that these putative species formed five respective, well-supported clusters within a distinct clade of the genus Acinetobacter which typically, although not exclusively, encompasses strains with strong haemolytic activity. The whole-genome-based average nucleotide identity (ANIb) values supported the species status of each of these clusters. Moreover, the distinctness and coherence of the clusters were supported by whole-cell profiling based on MALDI-TOF MS. Congruent with these findings were the results of metabolic and physiological testing. We conclude that the five putative taxa represent respective novel species, for which the names Acinetobacter courvalinii sp. nov. (type strain ANC 3623(T) =CCUG 67960(T) =CIP 110480(T) =CCM 8635(T)), Acinetobacter dispersus sp. nov. (type strain ANC 4105(T) =CCUG 67961(T) =CIP 110500(T) =CCM 8636(T)), Acinetobacter modestus sp. nov. (type strain NIPH 236(T) =CCUG 67964(T) =CIP 110444(T) =CCM 8639(T)), Acinetobacter proteolyticus sp. nov. (type strain NIPH 809(T) =CCUG 67965(T) =CIP 110482(T) =CCM 8640(T)) and Acinetobacter vivianii sp. nov. (type strain NIPH 2168(T) =CCUG 67967(T) =CIP 110483(T) =CCM 8642(T)) are proposed.