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Journal of Clinical Microbiology, February 2000, p. 595-599, Vol. 38, No. 2
Department of Medical Microbiology,
University of Zürich, CH-8028 Zürich, Switzerland
Received 22 June 1999/Returned for modification 24 August
1999/Accepted 4 November 1999
"Tropheryma whippelii"-associated infections are
usually confirmed histopathologically by using light microscopy. PCR
assays targeting the 16S rRNA gene (16S rDNA) of "T.
whippelii" are increasingly being applied for this purpose.
Compared to microscopic analysis, PCR seems to be more sensitive, as
indicated by the fact that several cases of Whipple's disease with
negative histopathological findings but positive PCR results have been
reported. Considering the lack of pathognomonic clinical features for
this disease and the fact that "T.
whippelii" DNA has repeatedly been found in patients
without clinical Whipple's disease, such PCR results should be
confirmed by additional tests. We have, therefore, evaluated a
"T. whippelii"-specific nested PCR targeting domain
III of the 23S rDNA with 41 clinical specimens known to contain
"T. whippelii" 16S rDNA. All of these specimens
were also positive for "T. whippelii" 23S rDNA. The
specificity of the test was shown by sequencing of the amplicons
and by the absence of amplicons in 38 negative controls. We consider
this PCR test to be a suitable tool for confirming
the presence of "T. whippelii" DNA in specimens
with inconclusive histopathological findings. The information derived from sequencing of the partial "T. whippelii" 23S
rDNA was then combined with our recent data of the 16S-23S rDNA
spacer region of this organism. Overall, four different rDNA types
are recognized in our proposed classification system for molecular
variants of "T. whippelii." This preliminary
scheme may provide a basis for further epidemiological and
clinical studies with "T. whippelii" and associated diseases.
0095-1137/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Evaluation of a Specific Nested PCR Targeting Domain III of
the 23S rRNA Gene of "Tropheryma whippelii" and
Proposal of a Classification System for Its Molecular
Variants
*
Corresponding author. Mailing address: Department of
Medical Microbiology, University of Zürich, Gloriastrasse 30, CH-8028 Zürich, Switzerland. Phone: 41-1-634-27-00. Fax:
41-1-634-49-06. E-mail: altwegg{at}immv.unizh.ch.
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