Journal of Clinical Microbiology, July 2001, p. 2634-2636, Vol. 39, No. 7
0095-1137/01/$04.00+0 DOI: 10.1128/JCM.39.7.2634-2636.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Molecular Identification of a Dietzia
maris Hip Prosthesis Infection Isolate
O.
Pidoux,1
J.-N.
Argenson,2
V.
Jacomo,1 and
M.
Drancourt1,*
Laboratoire de Bactériologie,
Epidémiologie et Hygiène hospitalières, Hôpital
Salvator,1 and Service de Chirurgie
Orthopédique et de Traumatologie, Hôpital
Sainte-Marguerite,2 Assistance
Publique-Hôpitaux de Marseille, Marseille, France
Received 11 August 2000/Returned for modification 26 November
2000/Accepted 23 April 2001
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ABSTRACT |
Dietzia maris, an environmental actinomycete, has been
implicated only once in human disease. We herein report the first
D. maris isolate from a bone biopsy specimen in a patient
hospitalized for a total hip prosthesis replacement. Cell wall fatty
acid analysis and 16S ribosomal DNA gene sequencing were utilized to
achieve its definite identification. This case report illustrates the usefulness of such methods for the accurate identification of actinomycetes.
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TEXT |
The genus Dietzia
includes two species of gram-positive, aerobic, mycolic acid-containing
actinomycetes that lack aerial mycelium (9). Dietzia
maris has been isolated from soil and from the skin and intestinal
tract of a carp (8, 9), and Dietzia natronolimnaios was isolated from an east African soda lake
(4). Previously classified as Rhodococcus maris
(8), D. maris has subsequently been transferred
to a new genus, Dietzia, proposed on the basis of the
peculiar structure of polar lipids, the presence of short-chain mycolic
acids, and 16S ribosomal DNA (rDNA) sequence-based phylogenetic
evidence (9). Although 13 environmental isolates of
D. maris have been reported (1-3, 7-11), only
one report of a human infection with this unusual bacterial species has
been published (2). We herein report on a case of total
hip prosthesis infection due to D. maris.
Case report.
A 48-year-old man was admitted for a left total
hip prosthesis replacement. His medical history included a traumatic
hip fracture and total hip prosthesis in 1982 and two total hip
prosthesis replacements for Staphylococcus epidermidis
infection with unstable prosthesis. In 1998, a relapse of S. epidermidis infection led to total hip prosthesis ablation and the
implantation of a vancomycin-impregnated cement spacer. Postoperative
local care given to the patient included the cleansing of the wound
with a physiological salt solution. Antibiotic treatment with
vancomycin, rifampin, and ofloxacine was administrated, and another hip
prosthesis was implanted in November 1999. At implantation, direct
examination of a Gram-stained surgical bone biopsy specimen disclosed
many leukocytes and gram-positive cocci that germinated into short rods
(Fig. 1A). The specimen did not exhibit
residual antibiotic activity as determined using a susceptible strain
of Micrococcus luteus and of S. epidermidis as
previously described (15). Culture of this specimen on 5% sheep blood agar (bioMérieux, Marcy l'Etoile, France) yielded rare, small, orange-pigmented colonies after 3 days of incubation at
37°C under aerobic conditions (Fig. 1B). The isolate was subcultured on 5% sheep blood agar and Mueller-Hinton agar (bioMérieux)
within 72 h at 37°C under aerobic conditions or a 10%
CO2 atmosphere and demonstrated short rods with coccoid
forms that did not form mycelia. It did not stain by the Ziehl-Neelsen
method. A test for catalase was positive. Biochemical characteristics
determined by API Coryne strip (bioMérieux) were in accordance to
those previously described (2, 5, 8, 9). Among the
variable characters, the isolate lacked urease activity, hydrolyzed
gelatin, and exhibited an alkaline phosphatase activity; it did not
utilized glucose or xylose as a carbon source (Table
1). The isolate, identified as D. maris, was susceptible to amoxicillin (MIC of <4 µg/ml),
imipenem (MIC of <4 µg/ml), gentamicin (MIC of 0.04 µg/ml),
pristinamycin (MIC of <2 µg/ml), trimethoprim-sulfamethoxazole (MIC
of 0.06 µg/ml), rifampin (MIC of 0.11 µg/ml), clindamycin (MIC of
<2 µg/ml), and vancomycin (MIC of <4 µg/ml). Antibiotic susceptibility was performed by the disk diffusion method on
Mueller-Hinton agar (bioMérieux) after 3 days of incubation at
37°C under aerobic conditions. All other microbiologic
investigations, including those of a set of blood cultures, superficial
specimen around the area of implantation, and spacer specimen, remained
negative. The patient was successfully treated with teicoplanin for 4 months.

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FIG. 1.
(A) Gram staining of a smear from a surgical biopsy
specimen reveals gram-positive cocci which germinate into short rods.
Magnification, ×1,000. (B) Growth of D. maris on 5% sheep
blood agar after 3 days of incubation at 37°C under aerobic
conditions, showing smooth and orange-pigmented colonies.
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