Genome-based taxonomic reclassification of Acinetobacter species using type and reference strains

Abstract

Acinetobacter species are widely distributed in the environment and clinical settings worldwide and serve as natural reservoirs of antimicrobial resistance genes and occasional human pathogens responsible for nosocomial infections. In this study, we performed genomic analysis of Acinetobacter seohaensis DSM 16313, a type strain of the proposed Acinetobacter species. This species was estimated to be evolutionary close to Acinetobacter towneri but the genome sequence of A. seohaensis was not publicly available. Pangenome analysis of the genome sequence of A. seohaensis along with those of genome-available type and reference strains of 82 Acinetobacter species including A. towneri suggested that three groups of Acinetobacter species, A. seohaensis and A. towneri; Acinetobacter pullorum and Acinetobacter portensis; and Acinetobacter idrijaensis, Acinetobacter mesopotamicus, and Acinetobacter lwoffii, were phylogenetically very similar to each other. Genome comparisons based on in silico DNA-DNA hybridization and the average nucleotide identity confirmed that these three groups of Acinetobacter species are conspecific. Based on the rules of priority, A. seohaensis, A. pullorum, and A. idrijaensis/A. mesopotamicus should be reclassified as later heterotypic synonyms of A. towneri, A. portensis, and A. lwoffii, respectively.