Arcobacter halophilus sp. nov., the first obligate halophile in the genus Arcobacter

1 Department of Microbiology, University of Hawaii, 2538 The Mall, Honolulu, Hawaii 96822, USA 2 School of Agricultural Science, University of Tasmania, Private Bag 54, Hobart, Tasmania 7001, Australia 3 Danish Institute for Food and Veterinary Research, Department of Microbiological Food Safety, Bülowsvej 27, DK-1790 Copenhagen V, Denmark Correspondence Maqsudul Alam alam{at}hawaii.edu A Gram-negative bacterium, designated LA31B T , was isolated from water collected from a hypersaline lagoon on Laysan Atoll in the north-western Hawaiian Islands. Single cells of LA31B T were slightly curved but became helical as their length increased. Preliminary characterization based on 16S rRNA gene sequence analysis showed that LA31B T shared 96·0 % identity with an Arcobacter sp. isolated from a cyanobacterial mat in hypersaline Lake Sinai, and 94 % identity with Arcobacter nitrofigilis , the type species of the genus Arcobacter . A polyphasic taxonomic study was conducted and confirmed the phylogenetic affiliation of strain LA31B T to the genus Arcobacter . However, LA31B T was found to be distinct from all recognized Arcobacter species, by a comprehensive biochemical test analysis, whole-cell fatty acid profiling, DNA G+C content (35 mol% in LA31B T ) and degree of DNA–DNA reassociation. Most notably, LA31B T was found to be an obligate halophile, a hitherto undescribed feature among recognized Arcobacter species. These data indicate that LA31B T should be considered to represent a novel species in the genus Arcobacter , for which the name Arcobacter halophilus sp. nov. is proposed. This is the first obligately halophilic member of the genus. The type strain is LA31B T (=ATCC BAA-1022 T =CIP 108450 T ). Published online ahead of print on 14 January 2005 as DOI 10.1099/ijs.0.63581-0. The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of LA31B T is AF513455 .