Avaliação do potencial patogénico dos genes sabA e hopZ de estirpes de Helicobacter Pylori isoladas numa população portuguesa

 A. Carvalho¹, M. Oleastro¹, B. Nunes², L. Monteiro

 

 

Resumo 

Estudo do potencial dos genes sabA e hopZ como marcadores de virulência para a doença ulcerosa péptica (DUP) em estirpes de H. pylori de doentes portugueses, 106 isoladas de adultos (50 com DUP, 56 com dispepsia não ulcerosa - DNU) e 74 isoladas de crianças (21 com DUP, 53 com DNU), por PCR e sequenciação.

O genótipo sabA on relacionou-se significativamente com a DNU em estirpes isoladas de crianças, enquanto que o genótipo hopZ on foi o mais prevalente em estirpes isoladas de doentes com DUP. Também se verificou a associação significativa entre o genótipo sabA on e os genótipos cagA-, vacAs2 e oipA off, nas estirpes isoladas de crianças, não tendo havido qualquer associação entre a funcionalidade de sabA e hopZ com outros genes, na população adulta. A análise de combinações de genótipos mostrou que, nas estirpes de crianças, o risco para a DUP aumentou quando se associou o genótipo sabA off aos genótipos cagA+, vacAs1 e cagA+/vacAs1.

Concluiu-se que os genes sabA e HopZ não constituem marcadores de virulência para DUP numa população Portuguesa. No entanto, sabA off pode contribuir para a distinção entre a DUP e a DNU, quando associado a outros marcadores de virulência.

 

Summary

To study the potential of sabA and hopZ genes as virulence markers for peptic ulcer disease (PUD) in H. pylori strains isolated from Portuguese patients, 106 isolated from adults (50 with PUD, 56 with non-ulcer dyspepsia) and 74 from children (21 with PUD, 53 with non-ulcer dyspepsia). Genotyping was performed by PCR and sequencing of the 5’ region of the genes was done.

We observed that sabA on was significantly more often associated with gastritis only in strains isolated from children. hopZ on was more prevalent in strains from PUD, although this difference was not significant. We also found that sabA on was significantly associated with cagA, vacAs2 and oipA off genotypes in the strains isolated from children and that there was no association between any functional status of sabA and hopZ with other genes in the adult population. Finally, we compared some genotype combinations. In strains isolated from children, the risk for PUD increased when sabA off was associated with: cagA+, vacAs1 and cagA+/vacAs1.

We concluded that neither sabA nor hopZ are pathogenicity markers for PUD in this Portuguese population. However, the sabA off genotype can contribute to the distinction between PUD and gastritis when associated with other virulence genes.

 

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Correspondência:

L. Monteiro

Centro de Bacteriologia.

Instituto Nacional de Saúde Dr. Ricardo Jorge

Av. Padre Cruz, 1649-016 Lisboa, Portugal

Tel.: +351-21-7519231

Fax: +351-21-7526400

e-mail: m.lurdes.monteiro@insa.min-saude.pt

 

(1) Unidade de Helicobacter/Campylobacter/ Centro de Bacteriologia, Instituto Nacional de Saúde Dr. Ricardo Jorge. Lisboa, Portugal.

(2) Observatório Nacional de Saúde, Instituto Nacional de Saúde Dr. Ricardo Jorge. Lisboa, Portugal.

 

Recebido para publicação: 11/11/2005

Aceite para publicação: 23/06/2006