Arcobacter anaerophilus sp. nov., isolated from an estuarine sediment and emended description of the genus Arcobacter

Abstract

Two strains (JC83, JC84T) of obligately anaerobic, H2S-producing bacteria were isolated from estuarine sediment samples collected from Gangasagar, West Bengal, India. Cells were Gram-stain-negative, non-motile rods. Both strains were positive for oxidase, negative for catalase, hydrolysed casein, reduced nitrate and utilized citrate. Both strains grew chemoorganoheterotrophically with optimal pH of 7-8 (range 7-10) and at 30 °C (range 25-37 °C). C16: 1ω7c, C18: 1ω7c, C16: 0 and C12: 0 were the major fatty acids of both strains with minor amounts of C14: 0, C12: 0 3-OH and C18: 0. Polar lipids of both strains included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylserine, phosphatidylcholine, phosphatidylinositol, an unidentified aminolipid (AL2), an unidentified phospholipid (PL2) and an unidentified lipid (L3). MK-6 was the major respiratory quinone. The DNA G+C content of strains JC83 and JC84T was 25.0 and 24.6 mol%, respectively. The strains showed DNA reassociation > 85 % (86.0±0.5 %) (based on DNA-DNA hybridization). Based on 16S rRNA gene sequence analysis, both strains were identified as belonging to the family Campylobacteraceae of the class Epsilonproteobacteria with Arcobacter marinus CL-S1T (95.4 % sequence similarity) as their closest phylogenetic neighbour. On the basis of morphological, physiological and chemotaxonomic characteristics as well as phylogenetic analysis, strains JC83 and JC84T are considered to represent a novel species, for which the name Arcobacter anaerophilus sp. nov. is proposed. The type strain is JC84T (= KCTC 15071T = MTCC 10956T = DSM 24636T). An emended description of the genus Arcobacter is provided. © 2013 IUMS.