Strain Acinetobacter mesopotamicus GC2 Does Not Represent a Novel Species, but Belongs to the Species Acinetobacter lwoffii as Revealed by Whole-Genome Sequence-Based Analysis

The formal scientific name Acinetobacter mesopotamicus has recently been proposed for bacterial strain GC2 isolated from soil (Curr Microbiol 77:3192-3200). However, the recalculation of the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) parameters revealed that their values for the genome sequences of GC2 and Acinetobacter lwoffii NCTC 5866(T) were as high as 95.7% and 66.1%, respectively. Moreover, the ANI and dDDH values for the genome of GC2 tested against those of 10 reference strains of A. lwoffii were 95.5-96.7% and 65.5-74.2%, respectively, and fall within the intraspecies range of these values known for A. lwoffii. These data indicate that strain GC2 belongs to A. lwoffii and contradicts the results of the authors of the proposal, who found the ANI and dDDH values for the GC2 and A. lwoffii DSM 2403(T) genomes to be 88.87% and 36.1%, respectively. The misclassification of strain GC2 is likely to result from the use of an incorrect reference genome sequence for in silico comparative analyses.

Automated summary

A bacterial strain GC2 isolated from soil was proposed as a new species, Acinetobacter mesopotamicus. However, reanalysis revealed that GC2 actually belongs to A. lwoffii, contradicting the proposed classification. This misclassification is likely due to the use of an incorrect reference genome sequence in comparative analyses.