Significant association of the dupA gene of Helicobacter pylori with duodenal ulcer development in a South-east Indian population.
A novel virulence factor, duodenal ulcer-promoting gene A (dupA), in Helicobacter pylori has been found to be associated with disease in certain populations but not in others. This study analysed a South-east Indian population as part of the debate about the relevance of dupA for the prediction of clinical outcomes. A total of 140 H. pylori strains isolated from duodenal ulcer (DU) (n = 83) and non-ulcer dyspepsia (NUD) patients (n = 57) were screened by PCR and dot-blot hybridization to determine the presence of the ORFs jhp0917 and jhp0918. Part of jhp0917-jhp0918 was sequenced to search for the C/T insertion that characterizes dupA and the levels of dupA transcripts were also assessed. The PCR and dot-blot results indicated the presence of jhp0917 and jhp0918 in 37.3 % (31/83) and 12.2 % (7/57) of H. pylori strains isolated from DU and NUD patients, respectively. Sequencing analysis showed insertion of a C at nt 1386 in the 3' region of jhp0917, forming the dupA gene in 35 strains. RT-PCR analysis detected the dupA transcript in 28 of these 35 strains. The expression level of the dupA transcript varied from strain to strain, as shown by real-time PCR. The results demonstrated that analysis based on PCR only for dupA may produce an erroneous interpretation. The prevalence of dupA was significantly greater among strains isolated from patients with DU than from patients with NUD in this population (P = 0.001, odds ratio = 4.26, confidence interval = 1.60-11.74). Based on these findings, dupA can be considered a biomarker for DU patients in India. The reported discrepancies for this putative virulence marker in different populations may be due to the genome plasticity of H. pylori.
National Institute of Cholera and Enteric Diseases, Kolkata 700010, India.
Jawed
J
Alam
IISER (Indian Institute of Science Education and Research), Kolkata, India.
Sankar
S
Maiti
National Institute of Cholera and Enteric Diseases, Kolkata 700010, India.
Prachetash
P
Ghosh
National Institute of Cholera and Enteric Diseases, Kolkata 700010, India.
Ronita
R
De
Centre for Liver Research, School of Digestive and Liver Diseases, Institute of Post Graduate Medical Education & Research, Kolkata, India.
Abhijit
A
Chowdhury
St John's Medical College Hospital, Bangalore, India.
Suryasnata
S
Das
St John's Medical College Hospital, Bangalore, India.
Ragini
R
Macaden
St John's Medical College Hospital, Bangalore, India.
Harshad
H
Devarbhavi
National Institute of Cholera and Enteric Diseases, Kolkata 700010, India.
T
T
Ramamurthy
National Institute of Cholera and Enteric Diseases, Kolkata 700010, India.
Asish K
AK
Mukhopadhyay
D000328:Adult; D000368:Aged; D001483:Base Sequence; D004381:Duodenal Ulcer / Q000453:epidemiology / Q000382:microbiology*; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D016481:Helicobacter Infections / Q000453:epidemiology / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D037521:Virulence Factors / Q000235:genetics*; D055815:Young Adult
C528428:DupA protein, Helicobacter pylori; D037521:Virulence Factors