Abstract
We studied a novel taxon of the genus Acinetobacter , which comprised six strains collected in Czechia, Germany, Indonesia and Turkey between 2015 and 2021. The organisms were isolated from environmental soil, water samples and cow faeces.
Their genome sizes varied between 3.3 and 3.5 Mb, with a G+C content of 40.4-40.8 mol%. Based on genus-wide core genome analysis, the taxon formed a distinct clade, with Acinetobacter gandensis being the phylogenetically closest related species.
The intrataxon genomic average nucleotide identity based on blast (ANIb) and digital DNA-DNA hybridization (dDDH) values reached 95.3-97.4% and 62.5-77.8 %, respectively, whereas its ANIb/dDDH values against the known Acinetobacter type strains were <=82.7 %/<=25.7 %. Cluster analysis of whole-cell MALDI-TOF mass spectra corroborated the distinctness and cohesiveness of the taxon.
The novel strains were non-glucose-oxidizing, non-haemolytic and non-proteolytic, growing at up to 37-41 °C but not at 44 °C and utilizing 8-10 of the 36 carbon sources tested. Growth on glutarate, tricarballylate and at 37 °C combined with the inability to assimilate 4-aminobutyrate and d-malate differentiated them from all validly named Acinetobacter species.
The inspection of genome sequences in the NCBI database revealed the existence of numerous strains conspecific with this group, which were collected from pig faeces and environmental samples in China. We conclude that the taxon represents an ecologically and geographically widespread species, for which we propose the name Acinetobacter amyesii sp. nov., with ANC 5579T (= CCM 9242T=CCUG 76274T=CNCTC 8134T) as the type strain.