Acinetobacter piscicola sp. nov., isolated from diseased farmed Murray cod (Maccullochella peelii peelii).

Abstract

A taxonomic study was carried out on strain LW15T, which was isolated from the external lesions of diseased farmed Murray cod (Maccullochella peelii peelii) from an intensive culture pond. Cells of strain LW15T were Gram-negative, facultative-anaerobic, non-motile, and both coccobacillus- and bacillus-shaped. Growth was observed at NaCl concentrations of 0-2 % (w/v) (optimum, 0 %), 4-32 °C (optimum, 25-28 °C) and pH 5.0-9.0 (optimum, 7.0). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain LW15T was affiliated to the genus Acinetobacter, showing the highest similarity to Acinetobacter guillouiae CIP 63.46T (97.7 %) and other Acinetobacter species with validly published names (93.5-97.6 %). Whole-genome sequencing and phylogeny reconstruction based on a core set of 1061 Acinetobacter genes indicated that strain LW15T was most closely related to the clade formed by A. guillouiae CIP 63.46T and Acinetobacter bereziniae CIP 70.12T and distantly related to any of the described species of genus Acinetobacter. Furthermore, strain LW15T could be distinguished from all known Acinetobacter species by its ability to assimilate β-alanine and l-arginine, but not d-glucose. The principal fatty acids were C18 : 1ω9c, C16 : 0 and C16 : 1ω7c/C16 : 1ω6c. The major respiratory quinone was Q-9. Polar lipids of strain LW15T comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, four phospholipids, aminolipid and two unknown lipids. Based on its phenotypic and genotypic data, strain LW15T represents a novel species of the genus Acinetobacter, for which the name Acinetobacterpiscicola sp. nov. is proposed. The type strain is LW15T (=MCCC 1K03337T=CICC 24241T=KCTC 62134T=JCM 32101T).