Association of IS605 and<i>cag</i>-PAI of<i>Helicobacter pylori</i>Isolated from Patients with Gastrointestinal Diseases in Taiwan

Lai, Chih Ho; Perng, Cherng-Kang; Lan, Keng‐Li; Lin, Hwai Jeng

doi:10.1155/2013/356217

Cited by 17 publications

(13 citation statements)

References 29 publications

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“…The frequency of cagE in our H. pylori isolates was also similar to previous reports from South Asia (Iran, 44.0%) [15] and East Asia (Malaysia, 59.0%) [50]. cagE and cagM genes were highly prevalent with frequencies of 96.0% and 97.0%, respectively, in H. pylori isolates cultured in Taiwan (East Asia) [51], whereas we found comparatively lower frequencies of cagE and cagM genes in our Pakistani clinical H. pylori isolates.…”

Section: Discussionsupporting

confidence: 91%

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Analysis of Clinical Isolates of Helicobacter pylori in Pakistan Reveals High Degrees of Pathogenicity and High Frequencies of Antibiotic Resistance

et al. 2014

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Background Antibiotic resistance in Helicobacter pylori contributes to failure in eradicating the infection and is most often due to point and missense mutations in a few key genes. Methods The antibiotic susceptibility profiles of H. pylori isolates from 46 Pakistani patients were determined by Etest. Resistance and pathogenicity genes were amplified, and sequences were analyzed to determine the presence of mutations. Results A high percentage of isolates (73.9%) were resistant to metronidazole (MTZ), with considerable resistance to clarithromycin (CLR; 47.8%) and amoxicillin (AML; 54.3%) also observed. Relatively few isolates were resistant to tetracycline (TET; 4.3%) or to ciprofloxacin (CIP; 13%). However, most isolates (n = 43) exhibited resistance to one or more antibiotics. MTZ-resistant isolates contained missense mutations in oxygen-independent NADPH nitroreductase (RdxA; 8 mutations found) and NADH flavin oxidoreductase (FrxA; 4 mutations found). In the 23S rRNA gene, responsible for CLR resistance, a new point mutation (A2181G) and 4 previously reported mutations were identified. Pathogenicity genes cagA, dupA, and vacA s1a/m1 were detected frequently in isolates which were also found to be resistant to MTZ, CLR, and AML. A high percentage of CagA and VacA seropositivity was also observed in these patients. Phylogenetic analysis of partial sequences showed uniform distribution of the 3′ region of cagA throughout the tree. Conclusions We have identified H. pylori isolates in Pakistan which harbor pathogenicity genes and worrying antibiotic resistance profiles as a result of having acquired multiple point and missense mutations. H. pylori eradication regimens should therefore be reevaluated in this setting.

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Section: Discussionsupporting

confidence: 91%

“…cagE and cagM genes were highly prevalent with frequencies of 96.0% and 97.0%, respectively, in H. pylori isolates cultured in Taiwan (East Asia) [51], whereas we found comparatively lower frequencies of cagE and cagM genes in our Pakistani clinical H. pylori isolates.…”

Section: Discussionmentioning

confidence: 52%

Analysis of Clinical Isolates of Helicobacter pylori in Pakistan Reveals High Degrees of Pathogenicity and High Frequencies of Antibiotic Resistance

et al. 2014

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“…When the studies were stratified by cagA+ H. pylori endemic (mostly East Asian populations) versus cagA non-endemic populations, an increased risk of pancreatic cancer was associated with blood type A in all populations, but with blood type B or AB only in cagA non-endemic populations (mostly Western populations) [31]. However, this observation is not supported in our cohort study in Taiwan, which is a cagA+ H. pylori endemic population [32]. The reasons for the diverse findings are unclear, but further assessment of interactions between ABO blood group and H. pylori carriage and other exposures could be informative.…”

Section: Discussionmentioning

confidence: 87%

ABO blood types and cancer risk—A cohort study of 339,432 subjects in Taiwan

Sun

Wen

Lin

et al. 2015

Cancer Epidemiology

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Background The associations of laboratory-based ABO phenotypes with cancer risks and mortality have not been systematically determined. Methods The study subjects were 339,432 healthy individuals with laboratory-based blood types from a Taiwan cohort. Results Compared to blood type O, blood type A was significantly associated with an elevated risk of stomach cancer incidence (Hazard Ratio [HR], 1.38 [95% CI, 1.11–1.72]) and mortality (HR, 1.38 [95% CI, 1.02–1.86]) compared with blood type O, after adjusting for age, sex, education, smoking, alcohol drinking, physical activity, and body mass index. Non-O blood types were associated with an elevated risk of pancreatic cancer, with blood type B reaching statistical significance for incidence (HR, 1.59 [95% CI, 1.02–2.48]) and mortality (HR, 1.63 [95% CI, 1.02–2.60]). In contrast, kidney cancer risk was inversely associated with blood type AB (HR, 0.41 [95% CI, 0.18–0.93]) compared to type O. Conclusion Cancer risks vary in people with different ABO blood types, with elevated risks of stomach cancer associated with blood type A and pancreatic cancer associated with non-O blood types (A, B, and AB).

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“…This finding could somewhat explain the variation in the clinical outcome of infected patients with distinct H. pylori strains. While there is some evidence regarding the effects of intact cagPAI on the severity of histopathological changes of the gastric tissue, ulceration, and carcinogenesis, establishment of this association needs further studies on different populations (39,(46)(47)(48).…”

Section: Discussionmentioning

confidence: 99%

Functional Cytotoxin Associated Gene A in Helicobacter pylori Strains and Its Association with Integrity of Cag-pathogenicity Island and Histopathological Changes of Gastric Tissue

Fazeli

Alebouyeh

Tavirani

et al. 2017

Arch Clin Infect Dis

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Objectives: Existence of cytotoxin associated gene A (cagA) is considered as a marker for detection of an oncogenic Helicobacter pylori strain. Expression of cagA in the strains with incomplete delivery system (partial CagPAI) could convert them to less virulent strains.This study was aimed to analyze expression of cagA in H. pylori strains presenting diverse cagPAI and its effect on histopathological changes of the gastric tissue. Methods: Clinical strains of H. pylori and related histopathological data were obtained to examine the presence of 12 cagPAI segments by PCR. Expression of cagA was analyzed by RT-PCR as well as Immunoblotting on RNA and protein extracts of the cagPAIpositive strains, respectively. In situe expression of CagA-positive strains was determined in a gastric epithelial cell line. Results: Intact cagPAI was detected among 33% (4/12) of H. pylori strains. Out of 7 diverse cagPAI genotypes in these strains, expression of cagA was confirmed in 2 strains with complete cagPAI at both RNA and protein levels. Occurrence of intestinal metaplasia and severe active gastritis were mainly detected in the strains with complete cagPAI genotype. No association was detected between EPIYA types of the strains and expression of cagA. Conclusions: These results collectively showed high diversity of cagA and cagPAI among the H. pylori strains. These diversities may provide some reasons to explain distinct disease severity caused by different H. pylori strains in the gastric tissue.

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Association of IS605 andcag-PAI ofHelicobacter pyloriIsolated from Patients with Gastrointestinal Diseases in Taiwan

Cited by 17 publications

References 29 publications

Analysis of Clinical Isolates of Helicobacter pylori in Pakistan Reveals High Degrees of Pathogenicity and High Frequencies of Antibiotic Resistance

Analysis of Clinical Isolates of Helicobacter pylori in Pakistan Reveals High Degrees of Pathogenicity and High Frequencies of Antibiotic Resistance

ABO blood types and cancer risk—A cohort study of 339,432 subjects in Taiwan

Functional Cytotoxin Associated Gene A in Helicobacter pylori Strains and Its Association with Integrity of Cag-pathogenicity Island and Histopathological Changes of Gastric Tissue

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