Cytotoxin-associated gene A and vacuolating cytotoxin A in human isolates of Helicobacter pylori and their association with the clinical status of ulcer disease.
OBJECTIVE
The aim of this study was to evaluate whether different Helicobacter pylori genotypes are associated with different clinical stages of peptic ulcer disease (PUD).


METHODS
We assessed the virulence characteristics of H. pylori isolates from patients with active PUD (presence of an ulcer crater at endoscopy) and from those with PUD in remission (normal endoscopic findings or scar not induced by drugs in PUD patients).


METHODS
H. pylori isolates from biopsies of the gastric antrum were examined for cagA and vacA genotypes by PCR amplification and Western blot analysis. Descriptive statistical techniques and multivariate polytomous logistic regression were used to estimate adjusted odds ratio (OR) for cagA and vacA genotypes in patients with active PUD or PUD in remission. Patients with non-ulcer dyspepsia (NUD) were used as negative controls.


RESULTS
The cagA genotype and phenotype were found to be differently associated with disease status. In fact, the multivariate regression model showed that gastric colonization by CagA+ H. pylori strains was associated with an increased risk of active PUD (OR 2.58), whereas the OR for patients with PUD in remission was 0.94.


CONCLUSIONS
Our data indicate that the active ulcer status is more strongly associated with H. pylori strains carrying the pathogenicity island (PAI) than remission status. These results support the hypothesis that a dynamic equilibrium exists among bacterial populations with or without the PAI, and that the relapse of the peptic ulcer could be consequent to expansion of the H. pylori population carrying the PAI.
Carattoli
A
A
Laboratorio di Batteriologia e Micologia Medica, Istituto Superiore di Sanità, Rome, Italy. alecara@ISS.IT
Pezzella
C
C
Pietroiusti
A
A
Galante
A
A
Pezzotti
P
P
Luzzi
I
I
D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000235:genetics*; D015153:Blotting, Western; D015870:Gene Expression; D005838:Genotype; D016481:Helicobacter Infections / Q000382:microbiology* / Q000473:pathology; D016480:Helicobacter pylori / Q000235:genetics* / Q000472:pathogenicity; D006801:Humans; D016015:Logistic Models; D010437:Peptic Ulcer / Q000382:microbiology* / Q000473:pathology; D016133:Polymerase Chain Reaction
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori