Acinetobacter thutiue sp. nov. Isolated from Oil-Contaminated Soil in Motorbike Repair Workshops

Two Acinetobacter isolates were found in soil samples from motorbike repair workshop floors in Vietnam. The two Acinetobacter isolates were Gram-stain-negative, coccobacilli-shaped, aerobic, non-motile, non-hemolytic, oxidase-negative, and catalase-positive. They were designated as strains VNH17(T) and VNK23. Their growth was inhibited by NaCl concentrations of >3%, and they grew at an optimal temperature of 20-35 C-degrees. Acidification of D-glucose and hydrolysis of gelatin were negative. They grew on beta-alanine, ethanol, L-histidine, D-malate, and L-ornithine whereas L-arginine, citrate, L-glutamate, and L-phenylalanine were not utilized. Core genome-based phylogenetic analysis revealed that the two isolated strains formed a lineage within the genus Acinetobacter in the family Moraxellaceae, the closest relative was Acinetobacter pavus (91.70-91.95%), and were grouped within a hemolytic clade with other closely-related relatives. The DNA G+C content of VNH17(T) and VNK23 was 42.07% and 41.75%, respectively. The average nucleotide identity and in silico DNA-DNA hybridization relatedness values (74.41-91.61% and 20.6-45.40%, respectively) between the Acinetobacter isolates and phylogenetically related type strains were below the threshold values used for species delineation. Based on genomic, chemotaxonomic, phenotypic, and phylogenomic analyses, the isolated strains represent novel species in the genus Acinetobacter, for which the name Acinetobacter thutiue sp. nov. (type strain VNH17(T) = KACC 23003(T) = CCTCC AB 2023063(T)) is proposed.