Relationship between Tobacco, cagA and vacA i1 Virulence Factors and Bacterial Load in Patients Infected by Helicobacter pylori

Abstract

Background and AimSeveral biological and epidemiological studies support a relationship between smoking and Helicobacter pylori (H. pylori) to increase the risk of pathology. However, there have been few studies on the potential synergistic association between specific cagA and vacA virulence factors and smoking in patients infected by Helicobacter pylori. We studied the relationship between smoking and cagA, vacA i1 virulence factors and bacterial load in H. pylori infected patients.MethodsBiopsies of the gastric corpus and antrum from 155 consecutive patients in whom there was clinical suspicion of infection by H. pylori were processed. In 106 patients H. pylori infection was detected. Molecular methods were used to quantify the number of microorganisms and presence of cagA and vacA i1 genes. A standardized questionnaire was used to obtain patients’ clinical data and lifestyle variables, including tobacco and alcohol consumption. Adjusted Odds Ratios (ORadjusted) were estimated by unconditional logistic regression.Results cagA was significantly associated with active-smoking at endoscope: ORadjusted 4.52. Evidence of association was found for vacA i1 (ORadjusted 3.15). Bacterial load was higher in active-smokers, although these differences did not yield statistical significance (median of 262.2 versus 79.4 copies of H. pylori per cell).ConclusionsThe association between smoking and a higher risk of being infected by a virulent bacterial population and with higher bacterial load, support a complex interaction between H. pylori infection and environmental factors.

Systematic review of the relationship of Helicobacter pylori infection with geographical latitude, average annual temperature and average daily sunshine

“…Due to the lack of related reports, the results of our analysis of the influence of smoking were inconsistent with those of previous studies [ 27 ]; further investigations are required for clarification of the influence of this factor on the rate of H. pylori infection.…”

Pathogenesis of Helicobacter pylori Infection

“…The findings of the study suggested that induction of IL‐8 and IL‐6 in airway epithelial cells had specific reaction against VacA stimulation. Consistently with this finding, a study on the specific relationship between smoking and bacterial load has noted the evidence of the association of vac A i1 type with active smoking .…”

Relationship between vacA Types and Development of Gastroduodenal Diseases

“…The findings of the study suggested that induction of IL-8 and IL-6 in airway epithelial cells had a specific reaction against VacA stimulation. Consistent with this finding, another study on the specific relationship between smoking and bacterial load has noted the evidence of the association of the vacA i1 genotype with active-smoking [ 69 ]. According to a report of the Surgeon General, the cardiovascular risks were reported to be attributable to active-smoking.…”