You can manage bookmarks using lists, please log in to your user account for this.
Media type:
E-Article
Title:
Heterogeneity of cag Genotypes in Helicobacter pylori Isolates from Human Biopsy Specimens
Contributor:
Tomasini, Maria Luisa;
Zanussi, Stefania;
Sozzi, Michele;
Tedeschi, Rosamaria;
Basaglia, Giancarlo;
De Paoli, Paolo
imprint:
American Society for Microbiology, 2003
Published in:Journal of Clinical Microbiology
Language:
English
DOI:
10.1128/jcm.41.3.976-980.2003
ISSN:
0095-1137;
1098-660X
Origination:
Footnote:
Description:
<jats:title>ABSTRACT</jats:title>
<jats:p>
The
<jats:italic>Helicobacter</jats:italic>
<jats:italic>pylori</jats:italic>
chromosomal cluster of genes known as the cytotoxin-associated gene (
<jats:italic>cag</jats:italic>
) island may have different compositions in infecting strains. In this study, we analyzed 150 single colonies obtained from gastric biopsy specimens from 10 patients infected with
<jats:italic>cagA</jats:italic>
-positive
<jats:italic>H</jats:italic>
.
<jats:italic>pylori</jats:italic>
strains and sweep isolates (isolates harvested with sweep in different points of the plate) from 6 patients infected with
<jats:italic>cagA</jats:italic>
-negative strains. Three loci in the
<jats:italic>cag</jats:italic>
island (
<jats:italic>cagA</jats:italic>
,
<jats:italic>cagE</jats:italic>
, and
<jats:italic>virB11</jats:italic>
) and the conserved gene
<jats:italic>glmM</jats:italic>
(
<jats:italic>ureC</jats:italic>
) were investigated by PCR. The levels of anti-
<jats:italic>H</jats:italic>
.
<jats:italic>pylori</jats:italic>
and anti-CagA antibodies in patient sera were also measured. For subjects infected with
<jats:italic>cagA</jats:italic>
-negative strains, all sweep isolates were also negative for
<jats:italic>cagE</jats:italic>
and
<jats:italic>virB11</jats:italic>
, suggesting the complete absence of the
<jats:italic>cag</jats:italic>
island. For subjects infected with
<jats:italic>cagA</jats:italic>
-positive strains, most of the isolates were positive for all three genes studied, whereas 24.7% of the isolates had a partial or total deletion of the
<jats:italic>cag</jats:italic>
island.
<jats:italic>cagA</jats:italic>
,
<jats:italic>cagE</jats:italic>
, and
<jats:italic>virB11</jats:italic>
were, respectively, present in 87.3, 77.3, and 90% of the colonies. The deletion of
<jats:italic>virB11</jats:italic>
was always associated with the deletion of
<jats:italic>cagA</jats:italic>
and/or
<jats:italic>cagE</jats:italic>
.
<jats:italic>H</jats:italic>
.
<jats:italic>pylori</jats:italic>
colonies with different
<jats:italic>cag</jats:italic>
genotypes were isolated within a single gastric biopsy specimen from 3 of the 10 patients and were further characterized by random amplified polymorphic DNA (RAPD) analysis and by sequencing of an arbitrarily selected gene segment. Although the colonies had different
<jats:italic>cag</jats:italic>
genotypes, their RAPD profiles were highly similar within each patient, and the nucleotide sequences of the selected gene segment were identical. All of the patients had detectable antibodies against
<jats:italic>H</jats:italic>
.
<jats:italic>pylori</jats:italic>
, and 9 of 10 had anti-CagA antibodies. In conclusion, we show that a single infecting
<jats:italic>H</jats:italic>
.
<jats:italic>pylori</jats:italic>
strain may include variable proportions of colony subtypes with different
<jats:italic>cag</jats:italic>
genotypes. The extension of our analysis to patients with well-characterized gastric diseases may provide significant information on the relationship between
<jats:italic>cag</jats:italic>
genotypes and clinical outcomes of
<jats:italic>H</jats:italic>
.
<jats:italic>pylori</jats:italic>
infections.
</jats:p>