Prevalence and risk factors for Helicobacter pylori transmission in the Eastern Cape Province application of immunological molecular and demographic methods
No Thumbnail Available
Date
2010
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Fort Hare
Abstract
Helicobacter pylori (H. pylori) is a microaerophilic, Gram-negative motile curved rod
that inhabits the gastric mucosa of the human stomach. The organism chronically infects
billions of people worldwide and is one of the most genetically diverse of bacterial
species. Infection with the organism potentially induces chronic gastritis and peptic ulcer
disease. In addition, H. pylori plays a role in the etiology of gastric cancer and gastric
MALT lymphoma. The risk of infection is increased in those living in the developing
world, which has been ascribed to precarious hygiene standards, crowded households,
and deficient sanitation common in this part of the world. Thus, the aim of this study was
to identify the risk factors in the transmission of H. pylori in our environment, i.e. in
Nkonkobe Municipality in the Eastern Cape Province, South Africa. Faecal samples were
collected from 356 apparently healthy subjects, consisting of 168 males and 188 females
aged from 3 months to 60 years (Mean = 31 years). A standardized questionnaire was
applied, it described demographic characteristics including age, sex, household hygiene,
socioeconomic status, area of residence, duration of stay in the area, sharing bath water,
sharing tooth brush, habit of sucking thumb, medication currently being taken or
medication taken within the past three months, source of water, type of toilet used,
education and occupation. A sandwich-type enzyme immunoassay amplification
technology (Amplified IDEIA
TM
Hp StAR
TM
, Oxoid, UK) was used to analyze the faecal
samples for the detection of H. pylori antigens using monoclonal antibodies specific for
H. pylori antigens. To assess the possibility of faecal oral route with tap water as an
intermediary link, PCR targeting the ureC (glmM), a highly conserved gene in H. pylori was carried out to detect H. pylori DNA in faecal samples of already positive samples by
HpSA test as well as in direct tap water used by the H. pylori positive subjects. QIAamp
DNA stool mini kit was used to extract DNA from faecal samples. Tap water samples
were then obtained using sterile bottles from areas inhabited by H. pylori positive
subjects as determined by HpSA test and PCR. DNA extraction from water samples was
done using UltraCleanTM Water DNA Isolation Kit (0.22μm) according to the
manufacturer’s instructions. PCR with primers specific for H. pylori glmM gene was
carried out with both positive and negative controls incorporated. Fisher’s exact test was
used to assess the univariate association between H. pylori infection and the possible risk
factors. Odds ratio (OR) and the corresponding 95% confidence interval (CI) were
calculated to measure the strength of association using EPI INFO 3.41 package. P values
of < .05 were required for significance. The precision rate of the diagnostic tests used was
also determined. H. pylori antigen was detected in 316 of the 356 subjects giving an
overall prevalence of 88.8%. Prevalence increased with age from 75.9% in children < 12
years age to 100% in the age group from 13 years to 24 years, also 100% prevalence of
H. pylori was recorded in young adults aged 25-47 years and subjects aged 60 years (P
< .05). H. pylori prevalence was higher in females than in males. Of 188 females who
participated in the study, H. pylori antigen was detected in 172 (91.5%) versus 144
(85.7%) of 168 males (P > .05). Interestingly, H pylori antigen was detected more often
(100%) in the high socioeconomic group than in those of low socioeconomic group
(85.9%). Sixteen (66.7%) of twenty four faecal samples that had previously tested
positive for the organism by HpSA test were confirmed positive by PCR. However none
of the treated tap water samples tested positive for the organism by PCR. The present study revealed a high prevalence of H. pylori in faecal samples of asymptomatic
individuals in the Nkonkobe Municipality, an indication of active infection. The obtained
results also revealed that direct treated tap water might not be playing a crucial role in the oral transmission of H. pylori in the studied population.
Description
Keywords
Helicobacter pylori., Bacterial diseases., Gastritis Risk factors., Bacterial diseases Risk factors., Gram-negative bacteria., Gram-negative bacterial infections., Helicobacter., Helicobacter infections., Helicobacter pylori South Africa, Eastern Cape.