Benefits of Helicobacter pylori cagE genotyping in addition to cagA genotyping: a Bulgarian study

Abstract

Associations of Helicobacter pylori cagE status with complex patient characteristics remain to be elucidated in Eastern Europe. The aim of this study was to assess the frequencies of cagE gene and cagA/cagE combinations in H. pylori strains from symptomatic Bulgarian patients and to improve cagA detection. cagA and cagE genotypes were evaluated in 219 patients with single-strain infections. In total, 84.9% of strains were cagA (+), while 68.5% were cagE (+). cagA (+), cagE (+), and cagA (+)/cagE (+) strains were more prevalent in peptic ulcer (93.8%, 84.4%, and 84.4%) compared with nonulcer patients (81.3%, 61.9%, and 61.3%, respectively). In elderly patients, cagE (+) and cagA (+)/cagE (+) strains were 1.9-fold more common than in the 12 children evaluated. Only 10% of the elderly subjects harbored low-virulence cagA (+)/cagE (-) strains compared with 16.8% of adults and 41.7% of children. Intriguingly, prevalence of the cagA (+)/cagE (-) genotype was 2.1-fold lower in men than in women, suggesting a higher frequency of more virulent strains in men. The presence of both cag genes and combinations was not linked to strain susceptibility to clarithromycin or metronidazole, place of residence, or prior therapy. Use of an extra primer pair increased cagA detection in 14.7% of 31 cagA (-) strains. In conclusion, use of a second primer pair for the cagA gene can be recommended in countries with common cagA (+) strains. Although both cag genes were linked to severe diseases in Bulgarian patients, the best discrimination of virulent strains was obtained by the cagA/cagE combination or by the cagE gene alone. cagE prevalence increased gradually with patient age, while the cagA (+)/cagE (-) genotype, implying a disrupted cag pathogenicity island, was associated with both younger age and female gender.

Non-invasive detection of Helicobacter pylori virulence genotypes ureA, vacA, cagA and babA2 among asymptomatic Egyptian infants

“…This rate agrees with results obtained from Brazil, and Bulgaria but was higher than that obtained in Portugal and United States (Oleastro et al, 2003;Podzorski et al, 2003;Garcia et al, 2010;Boyanova et al, 2011). The fact that H. pylori strains exhibit different patterns of adherence to gastric mucosa cells in adults and children can be an explanation of the low prevalence of babA2 in children (Blom et al, 2000).…”

Prevalence ofHelicobacter pylorivirulence genotypes among children in Eastern Turkey

“…We found that the iceA2 gene (57.1%) was the predominant genotype, supporting the findings of pediatric studies in Brazil (68.9%), Israel (52%), and the Midwestern United States (84%) [25,28,33] . The prevalence of cagE was found in 24.5% of H. pylori isolates in Israel [28] , 59% in Canada [5] , and 41.7% in Bulgaria [26] . The cagE gene was detected in 11 (22.4%) out of 49 isolates, and no significant association was found between the cagE and peptic ulcers in children in this study, consistent with a study by Benenson et al [28] .…”

“…The prevalence of H. pylori babA2 was 17.2% in Portugal, 36% in the Midwestern United States, 84.4% in Brazil, and 66.7% in Bulgaria [2,25,26,33] . In the present study, the babA2 gene was detected in 40.8% of the H. pylori isolates.…”

“…The inconsistent findings may be due to adaptation of H. pylori to the environment in different geographic regions [23] . Some studies had confirmed a significant correlation between the severity of histological changes and the presence of the cagA gene in the H. pylori genome [23][24][25][26] , whereas others [11,[27][28][29] have not emphasized this association.…”

Detection of virulence gene belonging to cag pathogenicity island in Helicobacter pylori isolates after multiple unsuccessful eradication therapy in Northwest Croatia

“…The frequent deletion of cagA3 compared to cagA1 and cagA2 in the control strains reported by Matar et al was attributed to decreases pathogenicity (9). Prevalence of cagA positive strains differs between the countries and is the highest in East Asia (90%), Japan (100%) (21) and Bulgaria (84.9%) (22). The moderate prevalence was found in Iran (62%) (23), Slovenia (61%) (24), Columbia (64%) (21), Turkey (49%) (25), Equador (46%) (26) and Portugal (31.8%) (27).…”