Abstract
We investigated a taxonomically novel group of the genus Acinetobacter , which included five strains isolated from soil and water samples collected in preserved forest areas in Czechia between 2013 and 2021. The whole-genome sequences of the strains were 3.1-3.2 Mb in size, with G+C contents of 38.0-38.2 mol%.
Core genome-based phylogenetic analysis showed that they formed a compact and deeply branched clade within the genus. The genomic average nucleotide identity based on blast/digital DNA-DNA hybridization values for the novel strains were 99.2-99.6 %/95.2-98.4 %, whereas those between the novel strains and the type strains of the known Acinetobacter species reached <78 %/<24 %.
The results of the genus-wide analysis of whole-cell MALDI-TOF mass spectra supported the sharp distinctness of the group. The five strains were non-glucose acidifying, nonhaemolytic, nonproteolytic and growing at 28 °C, but not at 32 °C; they assimilated acetate, benzoate, ethanol, l-histidine, 4-hydroxybenzoate, dl-lactate and malonate but not 4-aminobutyrate, l-aspartate or 2,3-butanediol; this phenotype is unique among the known Acinetobacter species.
We conclude that the five strains represent a novel environmental species, for which the name Acinetobacter silvestris sp. nov. is proposed, with the type strain ANC 4999T (=CCM 9207T=CCUG 75877T=CNCTC 8124T).