Polymerase chain reaction based analysis of the cytotoxin associated gene pathogenicity island of Helicobacter pylori from saliva: An approach for rapid molecular genotyping in relation to disease status

Abstract

Background and Aims:The genetic composition of the intricate cytotoxin associated gene pathogenicity island (cag PAI) of Helicobacter pylori is known to significantly influence the outcome of the disease. Hence, analysis of complete cag PAI of H. pylori isolated from saliva would be of immense importance in standardizing saliva as a reliable non-invasive diagnostic specimen and also to evaluate the type of H. pylori infection. The aim of the present study was to analyze the genes of cag PAI of H. pylori for their presence and correlating them with the disease status of the patients. Methods: One hundred and twenty patients (55 duodenal ulcer [DU], 25 gastric ulcer and 40 nonulcer dyspepsia [NUD]) were investigated for the present study. Eight pairs of oligonucleotide primers (cagA1, cagA2, cagAP1, cagAP2, cagE, cagT, LEC1 and LEC2) of five different loci; cagA, cagA promoter region, cagE which represents cagI region, cagT and LEC representing cagII were used to detect the presence of the cag PAI genes by polymerase chain reaction. Results: The comprehensive analysis of the genes constituting cag PAI showed almost equivalent prevalence of all the genes between both the study groups (ulcer and NUD) included. Little significant difference was found in the percentage distribution in both the clinical groups. cagE and cagT were found in a larger proportion of the ulcer group (92.5% and 96.2%) compared with the NUD group (77.5% and 85%), respectively. Conclusion: Saliva could be efficiently used as a non-invasive source for H. pylori and cagT might be an important locus of the cag PAI, thus greatly influencing the disease condition of the subjects.

Helicobacter pylori detection in gastric biopsies, saliva and dental plaque of Brazilian dyspeptic patients

“…Previous studies (Tiwari et al 2005, Loster et al 2006, Souto & Colombo 2008, Harris et al 2008) used PCR to diagnose an infection of H. pylori. These results are comparable to the results of the present study, in which there was a 95% success rate in the detection of H. pylori in the stomach.…”

“…Li et al (1995) found 75% of saliva samples to be positive, which is similar to the results of Wang et al (2002), who found the bacterium in 71% of saliva samples. Tiwari et al (2005) studied 120 dyspeptic patients and detected H. pylori in the gastric and saliva samples from each patient. Both authors suggested that saliva may be a method of transmission and may potentially induce gastric reinfections, which supports the results of the present study.…”

Association of smoking, alcohol and NSAIDs use with expression of cag A and cag T genes of Helicobacter pylori in salivary samples of asymptomatic subjects

“…DNA isolation from salivary samples was performed according to phenol chloroform C-TAB method [8] . All the steps were performed in aseptic conditions to minimize contamination using cryocentrifuge (Eppendorf).…”

“…Cag A and cag T have been implicated to play an important role in the disease progression and can be used as biomarkers of virulent disease causing state of H. pylori [8] .…”

“…Determination of H. pylori in saliva serves as an excellent non invasive tool to detect H. pylori in human subjects. A number of target genes have been proposed as candidates for the PCR detection of H. pylori [8] .…”