Identification, Clinical Significance, and Antimicrobial Susceptibilities
of Acinetobacter ursingii and Acinetobacter schindleri,
Two Frequently Misidentified Opportunistic Pathogens
Laurent Dortet, Patrick Legrand, Claude-James
Soussy, and Vincent Cattoir*
Laboratoire de Bactériologie-Virologie-Hygiène,
Centre Hospitalier Universitaire Henri Mondor, 94010 Créteil
The species belonging to the Acinetobacter
genus are currently reported as opportunistic pathogens in
hospitalized patients with underlying predispositions. However,
except for the Acinetobacter calcoaceticus-Acinetobacter
baumannii complex, the identification of other species
is frequently unreliable, especially for Acinetobacter
ursingii and Acinetobacter schindleri, newly
described in 2001. Thus, the clinical significance, phenotypic
features, and antimicrobial susceptibilities of these two
misidentified species remain unclear. Of 456 Acinetobacter
sp. clinical strains isolated from 2002 to 2005 in Henri Mondor
Hospital, 15 isolates (10 A. ursingii and 5 A.
schindleri isolates) were studied. They were characterized
using a phenotypic approach (API 20 NE and VITEK 2 systems),
16S rRNA gene sequencing, and susceptibility to antimicrobial
agents with evaluation of impact in clinical relevance. The
two corresponding type strains were also included for comparison.
All isolates were identified to the species level using molecular
tools, whereas the phenotypic methods remained unreliable
due to the absence of these two species in the manufacturers'
databases. However, the API 20 NE system appeared to be a
reasonably reliable phenotypic alternative for the identification
of A. ursingii when the numerical code 0000071 was
found. Conversely, no discriminative phenotypic alternative
existed for A. schindleri isolates. Concerning antimicrobial
susceptibility, A. ursingii strains appeared to be
more resistant to antibiotics than A. schindleri
strains, which could imply therapeutic consequences. Finally,
the prevalence of infections caused by A. ursingii
and A. schindleri (representing 9.7% and 4.8% of non-A.
calcoaceticus-A. baumannii complex strains, respectively)
seems to be underestimated.
ursingii;Acinetobacter schindleri;Acinetobacter sp;taxonomy.
Corresponding author: Tel 33 1 49 81 68
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