Journal of Clinical Microbiology, September 1998, p. 2597-2603, Vol. 36, No. 9
0095-1137/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Delft Diagnostic Laboratory,
Received 27 February 1998/Returned for modification 28 May
1998/Accepted 11 June 1998
The diversity of the gene encoding the vacuolating cytotoxin
(vacA) of Helicobacter pylori was analyzed in
98 isolates obtained from different geographic locations. The studies
focused on variation in the previously defined s and m regions of
vacA, as determined by PCR and direct sequencing.
Phylogenetic analysis revealed the existence of four distinct types of
s-region alleles: aside from the previously described s1a, s1b, and s2
allelic types, a novel subtype, designated s1c, was found. Subtype s1c
was observed exclusively in isolates from East Asia and appears to be
the major s1 allele in that part of the world. Three different allelic
forms (m1, m2a, and m2b) were detected in the m region. On the basis of
sequence alignments, universal PCR primers that allow effective
amplification of the s and m regions from H. pylori
isolates from all over the world were defined. Amplimers were
subsequently analyzed by reverse hybridization onto a line probe assay
(LiPA) that allows the simultaneous and highly specific hybridization
of the different vacA s- and m-region alleles and tests for
the presence of the cytotoxin-associated gene (cagA). This
PCR-LiPA method permits rapid analysis of the vacA and
cagA status of H. pylori strains for
clinical and epidemiological studies and will facilitate identification
of any further variations.
*
Corresponding author. Mailing address: Delft Diagnostic
Laboratory, R. de Graafweg 7, 2625 AD, Delft, The Netherlands. Phone: 31-15-2604577. Fax: 31-15-2604550. E-mail:
L.J.van.Doorn{at}ddl.nl.
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