Over 20 phenotypic characteristics were tested in representatives
of 10 species of the genus Arcobacter by using an
extensive biochemical identification scheme for species of
the genus Arcobacter and related bacteria as described by
On et al. (1996). Comparison of these test results
demonstrated several phenotypic differences between taxa.
The relevant phenotypic characteristics that differentiated
the novel strains from other taxa are given in Table 2. The
inability to reduce nitrate differentiates the novel isolates
from species with validly published names of the genus
Arcobacter, except for A. cibarius and A. mytili. The inability
to grow at 37 uC under aerobic conditions differentiates
the novel isolates from A. butzleri, A. skirrowii, A.
mytili, A. halophilus and A. marinus. The inability to grow
at 37 uC under microaerobic conditions distinguished the
novel isolates from A. cibarius. Furthermore, the novel
isolates could be differentiated from A. mytili based on
their ability to grow on medium containing 64 mg cefoperazone
l21 and to hydrolyse indoxyl acetate. In contrast
to A. halophilus and A. nitrofigilis, the novel isolates were
able to grow on non-supplemented Campylobacter charcoal-
deoxycholate base medium and were resistant to
cephalothin (32 mg l21) and cefoperazone (64 mg l21).
The novel isolates could be distinguished from A.
halophilus by the presence of catalase activity and growth
on medium containing 0.1% sodium deoxycholate. Furthermore,
their inability to show urease activity differentiated the
novel isolates from A. nitrofigilis. Apart from the inability to
grow at 37 uC and to reduce nitrate to nitrite, the novel
isolates can be distinguished fromA. marinus by the ability to
show catalase activity.