Detection of cagA and vacA genotypes of Helicobacter pylori isolates from a university hospital in Ankara region, Turkey

Abstract

The cagA and vacA profiles and their association with clinical findings show a distinct geographical distribution. In the present study, we aimed to determine the cagA status and vacA allelic subtypes in strains isolated from a university hospital in Ankara and to evaluate their associations with histopathological and endoscopic findings. Materials and methods:A total of 120 H. pylori strains from stock cultures positive for the ureA gene were randomly included in the present study. Of these strains, cagA and vacA allelic subtypes (s1a, s1b, s2, m1, m2) were examined by polymerase chain reaction.Results: Of the 120 strains, 64 (53.3%) were cagA-positive. However, no significant relationship was found between clinical outcomes and cagA positivity. There were 38 (33.6%) strains that had vacA m1 and 74 (65.5%) that had vacA m2 region. Overall, 75 (70.1%) samples were classified as vacA s1a, 3 (2.8%) as vacA s1b, and 29 (27.1%) as vacA s2. There was no significant relationship between vacA genotypes and endoscopic findings. The predominant vacA genotypes were s1am2 (35.6%) and s1am1 (33.6%), with almost the same rates. Furthermore, cagA positivity was found to be significantly related with the vacA s1am1 genotype. Conclusion:The cagA and vacA profiles of our study population are consistent with the Middle Eastern profile.

INVESTIGATION OF Helicobacter pylori VIRULENCE GENOTYPE IN GASTRIC BIOPSIES BY PCR

“…The s1b subtypes are rare in other regions and less virulent than other s1 subtypes [36,37]. The strains in the present study belong to western type, as studies indicated s1b subtype is rarely found in East-Asian countries [29,32,38]. Our results revealed m2 as the main allele that similar to studies from Iraq, Turkey, Iran, Saudi Arabia, and the middle east region characterized m2 as the main allele [14,32,33,[39][40][41][42].…”

“…However, the presence vacA gene within these isolates was increasing the pathogenicity and it had a statistically positive correlation with the disease (p=0.01 at a level 0.05). In comparison with the other studies that performed in the middle east region like Turkey and Egypt, which found vacAs1a allele is dominant (70.1% and 72.5%, respectively) than vacAs1b allele (2.8% and 7.2%, respectively) and 27.1% and 21.7%, respectively, as vacA s2 [32,33]. The allelotype s1a is more active than s1b [29], and with other vacA genotypes, the combination is associated with greater pathogenicity and virulence related to gastric cancer and peptic ulceration [34,35].…”

“…The strains in the present study belong to western type, as studies indicated s1b subtype is rarely found in East-Asian countries [29,32,38]. Our results revealed m2 as the main allele that similar to studies from Iraq, Turkey, Iran, Saudi Arabia, and the middle east region characterized m2 as the main allele [14,32,33,[39][40][41][42]. In another hand, some studies reported that the predominant vacA m subtype was m2 and no association or no role between vacA m genotypes and the development of peptic ulcer [2,32,33,42,43], whereas other studies had been found that vacA m1 strains are associated with high levels of inflammation in the gastric mucosa and increased the risk of gastric atrophy and carcinoma [2,44].…”

“…In another hand, some studies reported that the predominant vacA m subtype was m2 and no association or no role between vacA m genotypes and the development of peptic ulcer [2,32,33,42,43], whereas other studies had been found that vacA m1 strains are associated with high levels of inflammation in the gastric mucosa and increased the risk of gastric atrophy and carcinoma [2,44]. However, the results were different from country to others, but we consistent with different studies those of Middle Eastern countries, in which the vacA s1 and m2 subtypes have been predominant subtypes [32,42,45,46].…”

“…However, the results show there was a significant relationship between the presence of cagA and peptic ulceration p≤0.001; the significant association confirmed by previous reports from Iraq and Turkey [49,50] but the presence of cagA was higher than our finding this may be due to a regional area of research. Other middle eastern countries had been no significant between cagA status and incidence of diseases such as Turkey, Egypt, and Iran [30,32,39,42]. Among cagA positive strains, the most predominant vacA patterns in our study as shown in Table 3 were s1bm2 (50%), interestingly, cagA positive strains statistically correlated with s1m1 pattern p=0.04, odds ratio 6.60 (confidence interval 95% 1.05; 41.51), but not to others, p>0.05 for all others patterns.…”