[DNA fingerprinting of h. pylori isolates from Iranian patients by REP-PCR]

H. pylori has been implicated in peptic diseases, some with detrimental consequences such as ulcer or cancer. Since considerable genetic heterogeneity has been observed within H. pylori population worldwide, it appears an ideal achievement to recruit PCR-based methods and design genetic markers which recognize isolates from normal and symptomatic individuals. In this study 61 H. pylori isolates from dyspeptic patients were fingerprinted by REP-PCR. REP-PCR was performed on extracted DNAs of 61 H. pylori isolates from 39 normal, 18 ulcer and 4 cancer patients. Synthetic 18-nt primers, specific for interspersed repetitive elements in the bacterial genome, were recruited. PCR conditions were optimized and reproducibility of the reactions were confirmed. The size and number of PCR products were determined and DNA fingerprints of all isolates were analyzed by NTSYSpc programme, and dendrograms were generated. Results: Among 39 H. pylori isolates from normal patients 28 comprised a distinct cluster and 5 clustered along with isolates from ulcer patients. The remaining 6 isolates comprised a separate cluster distinct from other groups. Among 18 isolates from ulcer patients, 17 classified in a specific cluster, only one isolate was clustered along with isolates from normal patients. Isolates from cancer patients consisted a quite distinct cluster. In this study REP-PCR was used to show that majority of isolates from normal, ulcer, and cancer patients have distinct fingerprints which can be recruited for predicting the outcome of the infection with certain H. pylori isolates. It is concluded that REP-PCR is an effective and reproducible technique for fingerprinting H. pylori isolates from different human origins

[Study of the CagA gene prevalence in helicobacter pylori strains isolated from patients with upper gastrointestinal disorders in Iran]

Helicobacter pylori commonly is associated with gastritis: but only sometimes it causes clinically significant diseases such as gastric and duodenal ulcer. The development of disease depends on the virulence of the infecting H. pylori strain, the susceptibility of the host, and environment co-factors. The cytotoxin associated protein encoded by cagA gene is an important virulence factor that is produced by some H. pylori strains, and has been used as virulence marker in some populations. The aim of the study was to examine the prevalence of cagA gene in the isolated strains of H. pylori from patients with dyspeptic disease and to investigate the association of cagA gene and the severity of H. pylori related diseases in Iran. In this study, biopsy specimens were obtained from the antrum of 180 patients. After isolation of H. pylori and its DNA by standard methods, polymerase chain reaction [PCR] technique was used for detection of cagA bacterial gene. 92 out of the 180 patients had H. pylori strains. 70% were cagA gene positive. All patients with peptic ulcer [100%] and 44 out of 72 [61%] patients with non-ulcer dyspepsia were cagA positive [p<0.01]. There was significant difference in frequency of cagA gene in peptic ulcer disease and non-ulcer dyspepsia [p<0.01]. It showed that the risk of PUD in patients with cagA+ H. pylori infection may be higher than in those with cagA- H. pylori infection