Helicobacter pylori: evidence for spouse-to-spouse transmission

Large-scale, national, family-based epidemiological study on Helicobacter pylori infection in China: the time to change practice for related disease prevention

BACKGROUND AND AIMS

Current practice on Helicobacter pylori infection mostly focuses on individual-based care in the community, but family-based H. pylori management has recently been suggested as a better strategy for infection control. However, the family-based H. pylori infection status, risk factors and transmission pattern remain to be elucidated.

METHODS

From September 2021 to December 2021, 10 735 families (31 098 individuals) were enrolled from 29 of 31 provinces in mainland China to examine family-based H. pylori infection, related factors and transmission pattern. All family members were required to answer questionnaires and test for H. pylori infection.

RESULTS

Among all participants, the average individual-based H. pylori infection rate was 40.66%, with 43.45% for adults and 20.55% for children and adolescents. Family-based infection rates ranged from 50.27% to 85.06% among the 29 provinces, with an average rate of 71.21%. In 28.87% (3099/10 735) of enrolled families, there were no infections; the remaining 71.13% (7636/10 735) of families had 1-7 infected members, and in 19.70% (1504/7636), all members were infected. Among 7961 enrolled couples, 33.21% had no infection, but in 22.99%, both were infected. Childhood infection was significantly associated with parental infection. Independent risk factors for household infection were infected family members (eg, five infected members: OR 2.72, 95% CI 1.86 to 4.00), living in highly infected areas (eg, northwest China: OR 1.83, 95% CI 1.57 to 2.13), and large families in a household (eg, family of three: OR 1.97, 95% CI 1.76 to 2.21). However, family members with higher education and income levels (OR 0.85, 95% CI 0.79 to 0.91), using serving spoons or chopsticks, more generations in a household (eg, three generations: OR 0.79, 95% CI 0.68 to 0.92), and who were younger (OR 0.57, 95% CI 0.46 to 0.70) had lower infection rates (p<0.05).

CONCLUSION

Familial H. pylori infection rate is high in general household in China. Exposure to infected family members is likely the major source of its spread. These results provide supporting evidence for the strategic changes from H. pylori individual-based treatment to family-based management, and the notion has important clinical and public health implications for infection control and related disease prevention.

Helicobacter pylori acquisition rates and the associated risk factors amongst newlywed couples; a prospective cohort study in Tehran, Iran

BACKGROUND

The rates and routes of Helicobacter pylori transmission, in a high prevalent country like Iran, with gastric cancer as the leading cause of male cancer mortality is of essence. Here, we have studied the H. pylori-associated risk factors and the likelihood of interspousal transmission.

METHODS

In a cohort of 686 young prewed couples, questionnaires were self-administered and serum samples were collected, for assessment of risk factors and sero-status of H. pylori, at baseline and follow-up. Of the 475 H. pylori single- or double-seronegative couples, 201 returned for follow-up. The average follow-up duration was 2.2 (SD 0.6) years, with a total of 560.1 person-years. Logistic regression and Cox regression models were used to estimate the odds ratios (ORs) and hazard ratios (HRs).

RESULTS

The risk of infection was higher in men than women (OR:1.3, 95%CI:1.0-1.8) and among metropolitan than rural residents (OR=1.4, 95%CI:1.1-1.9). The risk of infection was significantly higher among those with three siblings (OR=1.6, 95%CI:1.1-2.2), and four or more siblings (OR=1.4, 95%CI:1.0-1.9), in reference to those with one or no siblings. H. pylori acquisition occurred in 10.9% (27/247) of the H. pylori seronegative participants. The risk of acquisition was significantly higher in older aged (HR=1.2, 95%CI: 1.1-1.3) and higher educated (HR=0.2, 95%CI:0.1-0.9) participants, than younger and illiterate subjects, respectively. Our analysis did not find any evidence for interspousal transmission (HR=1.0, 95%CI: 0.4-2.2).

CONCLUSION

Although we detected H. pylori acquisition in the young adult Iranian population, our findings did not support interspousal transmission, as a mode of adult H. pylori aquisition.

Concurrence of Helicobacter pylori Infection and Its Associated Factors in Korean Couples

Background

This study evaluated the prevalence of Helicobacter pylori infection and the risk factors associated with H. pylori transmission among spouses.

Methods

We assessed the spousal concurrence of H. pylori infection using the Campylobacter-like organism (CLO) test under gastro-endoscopy in 132 couples. Based on the CLO test results, participants were categorized into H. pylori concurrent and independent groups. The chi-square test and Student t-test were performed for demographic comparisons between the concurrent and independent H. pylori groups. In addition, multivariate logistic regression analysis was performed to identify factors associated with concurrent H. pylori infection.

Results

The study revealed that the concurrence rate of H. pylori infection was 42.4% in married Korean couples. The odds ratio (OR) derived from the concurrence of H. pylori infection tended to decrease in older couples (OR, 0.975; 95% confidence interval [CI], 0.949-1.002; P=0.072). Gastric erosion was also associated with a decreased OR for concurrent infection (OR, 0.488; 95% CI, 0.295-0.808; P=0.005). Conversely, active duodenal ulcers were associated with an increased OR for concurrent infections (OR, 6.501; 95% CI, 1.267-33.346; P=0.025). Duodenal ulcer scars tended to increase the OR of concurrent infections (OR, 1.392; 95% CI, 0.815-2.380; P=0.226).

Conclusion

Spousal transmission and concurrence of H. pylori infection were negatively associated with gastric erosion; however, they were positively associated with active duodenal ulcers. Further studies are warranted to elucidate the mechanisms underlying these findings.

Management of Helicobacter pylori infection: The Bhubaneswar Consensus Report of the Indian Society of Gastroenterology

The Indian Society of Gastroenterology (ISG) felt the need to organize a consensus on Helicobacter pylori (H. pylori) infection and to update the current management of H. pylori infection; hence, ISG constituted the ISG's Task Force on Helicobacter pylori. The Task Force on H. pylori undertook an exercise to produce consensus statements on H. pylori infection. Twenty-five experts from different parts of India, including gastroenterologists, pathologists, surgeons, epidemiologists, pediatricians, and microbiologists participated in the meeting. The participants were allocated to one of following sections for the meeting: Epidemiology of H. pylori infection in India and H. pylori associated conditions; diagnosis; treatment and retreatment; H. pylori and gastric cancer, and H. pylori prevention/public health. Each group reviewed all published literature on H. pylori infection with special reference to the Indian scenario and prepared appropriate statements on different aspects for voting and consensus development. This consensus, which was produced through a modified Delphi process including two rounds of face-to-face meetings, reflects our current understanding and recommendations for the diagnosis and management of H. pylori infection. These consensus should serve as a reference for not only guiding treatment of H. pylori infection but also to guide future research on the subject.

Prevalence and Risk Factors of Helicobacter pylori Infection among Children Aged 1 to 15 Years at Holy Innocents Children's Hospital, Mbarara, South Western Uganda

Background

Helicobacter pylori infection affects more than half of the world's population. The infection is generally acquired during childhood but can remain asymptomatic, with long-term clinical sequelae including gastritis, peptic ulcer disease, and stomach cancer.

Methods

The study was approved by Institutional Review Committee of Mbarara University of Science and Technology. After obtaining informed consent from parents/legal guardians, illegible children who presented with gastrointestinal complaints at Holy Innocents Children's Hospital were recruited; structured questionnaires were administered to the parents/guardians to collect information on sociodemographic data and risk factors of H. pylori infection. Four (4) millilitres of blood was collected from each child and tested for H. pylori blood Antibody test and stool specimens were used for H. pylori antigen test.

Results

The prevalence of H. pylori infection among the study participants was 24.3%. The infection rate increased with increase in age of the participants, from 16.2% among 1to 5 years old to 27.2% among 6 to 10 years. Infections were higher among school going children (68/74, p=0.003, OR 3.9; CI: 1.5 to 10.6) and children from crowded households (59/74, p<0.001, OR 2.6, and CI 1.3 to 5.0), unsafe source of drinking water at schools (46/74, p=0.003), and lack of sanitary facility at homes (57/74, p=0.001, and OR 1.6 CI 0.7 to 3.6).

Conclusion

The prevalence of H. pylori infection among children aged 1 to 15 years at Holy Innocents Children's Hospital was high and increases with age. School attendance, lack of sanitary facility, lack of safe drinking water, and overcrowding were the risk factors associated with H. pylori infection.

Prevalence of Helicobacter pylori infection in sexual partners of H. pylori-infected subjects: Role of gastroesophageal reflux

Background

Helicobacter pylori is transmitted through faecal-oral or oral-oral routes. Whether H. pylori infection is more prevalent in sexual partners of H. pylori-infected subjects is unclear.

Objective

We evaluated 1) the prevalence of H. pylori infection in sexual partners of H. pylori-infected subjects; and 2) whether presence of gastroesophageal reflux in H. pylori-infected subjects was associated with transmission of infection to their sexual partners.

Methods

We evaluated H. pylori infection by 13C Urea Breath Test in sexual partners of 161 consecutive patients with H. pylori-related dyspepsia. The case-control group consisted of 161 dyspeptic subjects undergoing the 13C Urea Breath Test. The prevalence of reflux symptoms was noted through the Leeds scale. The role of gastroesophageal reflux in transmission of H. pylori infection was evaluated by binary logistic regression. A two-tailed p value of 0.05 or less was considered significant.

Results

Prevalence of H. pylori infection in sexual partners of H. pylori-infected subjects is 74.5% whereas prevalence of H. pylori infection in the control group is 32.3%, p<0.05. At the logistic regression analysis, the presence of reflux symptoms in H. pylori-infected subjects is independently associated with concomitant infection in both members of the couple (odds ratio 4.41, 95% confidence interval 1.6-12.3) and with length of cohabitation (odds ratio 2.39, 95% confidence interval 1.0-5.7).

Conclusions

The prevalence of H. pylori infection is significantly higher in sexual partners of H. pylori-infected subjects than in controls. Members of a couple are four times more likely to be both H. pylori infected if one of the couple has reflux symptoms.

Helicobacter pylori: A foodborne pathogen?

Helicobacter pylori (H. pylori) is an organism that is widespread in the human population and is sometimes responsible for some of the most common chronic clinical disorders of the upper gastrointestinal tract in humans, such as chronic-active gastritis, duodenal and gastric ulcer disease, low-grade B-cell mucosa associated lymphoid tissue lymphoma of the stomach, and gastric adenocarcinoma, which is the third leading cause of cancer death worldwide. The routes of infection have not yet been firmly established, and different routes of transmission have been suggested, although the most commonly accepted hypothesis is that infection takes place through the faecal-oral route and that contaminated water and foods might play an important role in transmission of the microorganism to humans. Furthermore, several authors have considered H. pylori to be a foodborne pathogen because of some of its microbiological and epidemiological characteristics. H. pylori has been detected in drinking water, seawater, vegetables and foods of animal origin. H. pylori survives in complex foodstuffs such as milk, vegetables and ready-to-eat foods. This review article presents an overview of the present knowledge on the microbiological aspects in terms of phenotypic characteristics and growth requirements of H. pylori, focusing on the potential role that foodstuffs and water may play in the transmission of the pathogen to humans and the methods successfully used for the detection of this microorganism in foodstuffs and water.

Helicobacter pylori infection in family members of patients with gastroduodenal symptoms. A cross-sectional analytical study

BACKGROUND

Primary Helicobacter pylori (H. pylori) infection is acquired predominantly in childhood in the family setting. We aimed to investigate the presence of intrafamilial concurrent H. pylori infection.

DESIGN AND SETTING

Cross-sectional analytical study with a control group, conducted in a tertiary care hospital.

METHODS

Fifty adult patients with gastroduodenal symptoms who underwent gastroscopy (index parents), their spouses and their children were enrolled in the study. Blood samples were collected from all of the study subjects to test for immunoglobulin G (IgG) antibody response. H. pylori antigen was investigated in the stool specimens of children only.

RESULTS

The participants were divided into two groups: Group 1 consisted of the 40 patients in whom H. pylori infection was demonstrated via endoscopy, their spouses and their children. Group 2 included the remaining 10 patients who underwent endoscopy revealing negative results for H. pylori, their spouses and their children. IgG antibodies were present in all of the index parents, 95% of their spouses and 93% of their children in group 1; 13 of the children (9%) were also positive for H. pylori stool antigen (HpSA). However, IgG antibodies were present in only 2 of the 10 index parents in group 2. One of their spouses and one of their children had a positive antibody response. All of their children had negative stool antigen test results.

CONCLUSION

H. pylori infections exhibit intrafamilial clustering. Parental infection, age ≥ years and having three or more siblings are the major risk factors for H. pylori infection in children.

Are the view of Helicobacter pylori colonized in the oral cavity an illusion?

Urea breath test (UBT), as a leading preferred non-invasive diagnostic technology, but may not be able to detect oral H. pylori. With negative results of UBT, the patient may have an oral infection. On the basis of the fact of success, eradication rate may increase by 21% in the 95% Cl range after the elimination of oral H. pylori, the author believes oral H. pylori does exist and the oral cavity is the second colonized site aside its primary site of the stomach. H. pylori migrated out of Africa along with its human host circa 60 000 years ago; they are not lives in stomach only. In this review article, evidence established in recent years studies with use more appropriate technology had been listed and discussed. The author considers the oral cavity is a black hole for H. pylori infection that significant effective on gastroenterology and another medical field. The role of the oral cavity as the source of H. pylori infection is so controvert in past years. It seems like a human being having a second-time face to discover H. pylori in the history.

Is There Any Advantage of Treating Partners in Helicobacter pylori Eradication?

Aim. We designed this trial to find answers to the following questions. (1) Does the success rate decrease in a country where HP prevalence is high? (2) Can we provide benefit by simultaneously treating the partners of infected patients? Materials and Methods. The first group consisted of 102 HP-positive patients, and both the patients and their HP-positive partners were treated. The second group consisted of 104 HP-positive patients whose partners were HP-positive but only the patients were treated. The participants in both groups were treated with levofloxacin 500 mg daily, amoxicillin 1 g b.i.d, and lansoprazole 30 mg b.i.d (LAL) for ten days. Results. In the per-protocol analysis, the eradication success rate was found to be 92.2% (94/8) in the first group and 90.4% (94/10) in the second group. No statistically significant difference was found between the two groups (P > 0.05). Conclusions. With regard to the HP eradication rate, no difference was found between treating the HP-positive partners of HP-positive patients simultaneously and not treating them simultaneously. According to these results, we can say that reinfections between partners do not significantly contribute to the failure of eradication.

Helicobacter pyloriInfection: A Global Occupational Risk for Healthcare Workers?

The occupational risks from Helicobacter pylori, a major cause of gastroduodenal diseases, were reviewed for selected groups of healthcare workers (HCWs). A literature search was performed using Medline/Pubmed, 1983 to June 2003. Additional manual searches were made using reference lists from the selected articles. Current knowledge implies various pathways of agent transmission, favoring person-to-person transmission. The risks are highest for gastroenterologists, some nurses, and employees caring for persons with mental disability. Results for other groups are conflicting.

Seroprevalence of Helicobacter pylori in female Vietnamese immigrants to Korea

AIM: To investigate the seroprevalence of Helicobacter pylori (H. pylori) and its relationship to nutritional factors in female Vietnamese immigrants to Korea.

METHODS: A total of 390 female immigrants from Vietnam and 206 Korean male spouses participated in the study. Blood samples from 321 female immigrants and 201 Korean male spouses were analyzed for H. pylori antibodies. Data on age, sex, alcohol consumption, smoking status, dietary nutritional factors and gastrointestinal symptoms were collected using questionnaires. The daily intakes of the following nutrients were estimated: energy, protein, niacin, lipid, fiber, calcium, iron, sodium, potassium, zinc, folate, cholesterol, and vitamins A, B1, B2, B6, C and E.

RESULTS: The prevalence of H. pylori positivity was lower in the immigrants than in age-matched Korean females (55.7% vs 71.4%, respectively; P < 0.0001) and the domestic population of Vietnam. The prevalence of H. pylori positivity among married couples was 31.7% for both spouses. There were no statistically significant differences in the incidence of smoking, amount of alcohol consumed, or nutritional factors between the H. pylori-positive and negative groups.

CONCLUSION: The prevalence of H. pylori positivity was lower among female Vietnamese immigrants than among Korean females. Nutritional factors did not differ between the H. pylori-positive and negative groups.

Transmission pathway of Helicobacter pylori: does food play a role in rural and urban areas?

Helicobacter pylori is a Gram-negative microaerophilic bacterium that has colonized the human gastric mucosa. This infection is very common and affects more than half of the human population. The prevalence is however unbalanced between rural developing areas (more than 80%) and urban developed areas (less than 40%). H. pylori is responsible for several pathologies, such as gastritis, peptic ulcer and gastric cancer but its transmission pathway is still not clear. The risk factors for H. pylori infection include poor social and economic development; poor hygienic practices; absence of hygienic drinking water; and unsanitary prepared food. There is evidence supporting a gastro-oral, oral-oral and faecal-oral transmission, but no predominant mechanism of transmission has been yet identified. Transmission may occur in a vertical mode (e.g. from parents to child) or in a horizontal mode (across individuals or from environmental contamination). In either case, the involvement of water and food cannot be excluded as vehicles or sources of infection. Indirect evidence of presence of H. pylori in water and food, namely the detection of its DNA and survival studies after artificial contamination of food and water has been described. This paper reviews data both favourable and against the role of water and food in the transmission of H. pylori, exploring their role as a potential transmission vehicle for person-to-person and food-chain transmission. The likelihood of the transmission pathway in developing rural and developed urban areas appears to be different. In developed areas, person-to-person transmission within families appears to be dominant, while in the rural developing areas the transmission pathway appears to be more complex. In this later case, the transmission by contaminated food, water, or via intensive contact between infants and non-parental caretakers may have a greater influence than within-family transmission.

The transmission of Helicobacter pylori: the effects of analysis method and study population on inference

Although much is known about the virulence of Helicobacter pylori, the transmission pathways for this bacterium are still unresolved. Transmission has been addressed through: (1) prevalence within families; (2) detection in fecal/oral environments; (3) detection in the abiotic/biotic environment; and (4) direct inference from strain similarity. Here, we review the molecular and biochemical methods used and discuss the relative merits of each. Furthermore, as there are differences between developing and developed nations, we discuss the results obtained from transmission studies in light of the study population. We conclude that H. pylori is probably transmitted person-to-person, facilitated by fecal-oral transmission during episodes of diarrhea or gastro-oral contact during periods of vomiting. The persistence of H. pylori in abiotic and biotic environments remains unproven but possible reactivation from viable, non-culturable coccoid forms should be further investigated. Finally, we speculate on the effect of host-pathogen interactions in confounding the inference of transmission.

Is Helicobacter pylori a pathogenic agent of the cervix uteri?

BACKGROUND

Helicobacter pylori is a gram-negative, microaerophilic rod-shaped bacterium that lives beneath the gastric mucosal layers, on the surface of epithelial cells. Gastric infection with this organism causes inflammation of the gastric mucosa, which can lead to gastritis, duodenal or gastric ulcers and even in rare cases to gastric carcinoma or MALT lymphoma. Approximately 50% of the population of the entire world is believed to be infected with H. pylori, but the exact route of transmission is still uncertain. It has been speculated that the cervix, with its endocervical columnar epithelium and acidic mucous layer, might provide a suitable environment for H. pylori. H. pylori might be a pathogenic agent for cervical infection. In order to address this issue we studied H. pylori in the endocervical tissue.

METHODS

To investigate our hypothesis, we examined cervical tissue using PCR, culture, and Gram-stain. Thirty-three cervices from women who underwent total hysterectomy for noninvasive non-cervical benign uterine diseases were analyzed in this study. Twenty-one patients had cervicitis and 12 patients were included as controls.

RESULTS

Of the 29 patients studied, none showed evidence of H. pylori infection. H. pylori was not detected by PCR, histology, or culture.

CONCLUSIONS

We could not detect H. pylori in the cervix of patients with cervicitis. H. pylori-infected patients' cervices remain to be investigated, and a larger study is needed to draw firm conclusions.

The recurrence of Helicobacter pylori infection: incidence and variables influencing it. A critical review

The rate of H. pylori recurrence after eradication of the microorganism seems to be relatively low, at least in developed countries, where the mean annual reinfection rate is of approximately 3% per patient-year of follow-up, although the risk of reinfection in some developing regions is considerably higher. Several findings suggest that recrudescence rather than reinfection is likely to be responsible for most cases of recurrence: (i) the recurrences decrease with time and decline sharply after the first year, and (ii) studies using molecular fingerprinting techniques (polymerase chain reaction [PCR]) confirm that the identified microorganisms (before and after therapy) are usually genetically identical. The lower the efficacy of an antibiotic therapy, the greater the likelihood that recurrence occur, again suggesting that in these cases temporary "clearance" has been achieved rather than true eradication. The value of the (13)C-urea breath test after treatment is higher in those patients who suffer a recurrence; therefore, selection of a lower cut-off value may be helpful to maintain the diagnostic accuracy of posttreatment breath test, and thus preventing recrudescences. The observation of a pattern of histological (active) gastritis without the concomitant finding of H. pylori must raise the suspicion of a diagnostic error. Some studies suggest that recurrence is relatively infrequent, even if the patient's spouse is H. pylori-positive, suggesting that the patient's partner does not act as a reservoir for the reinfection. However, other investigators achieve contrary results, although a common exogenous source of H. pylori (for both partner's infection and patient's reinfection) cannot be ruled out. The oral cavity may be a potential source for recrudescence of gastric infection after successful therapy. When peptic ulcer reappears (sometimes with bleeding recurrence) or gastric MALT (mucosa-associated lymphoid tissue) lymphoma relapses after previous H. pylori eradication, recolonization of the gastric mucosa by the organism has almost always occurred.

Evidence of mother-child transmission of Helicobacter pylori infection

BACKGROUND

Low socioeconomical status is a major risk factor for natural acquisition of Helicobacter pylori (H. pylori) infection in developing countries. Its transmission route is unknown but studies suggest person-to-person transmission.

AIM

To evaluate seropositivity of anti-H. pylori antibodies in family members of infected symptomatic index patients as compared to family members of symptomatic uninfected index patients.

PATIENTS AND METHODS

One hundred and twelve family members of 38 patients who underwent endoscopy to exclude peptic disease were studied. Patients were deemed H. pylori infected or not infected when rapid urease test and histology were both positive or both negative. The family members underwent ELISA serology using the Cobas Core II Kit (Roche) and were classified into three groups: I - 29 family members of 10 H. pylori (+) duodenal ulcer index patients; II - 57 family members of 17 H. pylori (+) index patients without duodenal ulcer; III - 26 family members of 11 H. pylori (-) index patients.

RESULTS

Seropositivity of group I and II (infected patients) was higher than the control group, 83% vs 38%, specially in mothers, 81% vs 18%, and in siblings 76% vs 20%. Differences between fathers' seropositivity was not statistically significant in the three groups: 100% vs 86% vs 70%. Seropositivity of all family members (mother, father and siblings) between infected group (I vs II) was similar.

CONCLUSION

Prevalence of H. pylori infection was higher in family members of infected patients, but was similar among family members of infected patients with and without duodenal ulcer. H. pylori infection is more frequent in mothers and siblings of infected index children. A common source of infection cannot be excluded, but facts suggest that person-to-person transmission occurs, specially from mother to child.

Concordance of Helicobacter pylori strains within families

Helicobacter pylori infection is typically acquired in early childhood, and a predominantly intrafamilial transmission has been postulated. To what extent family members share the same strains is poorly documented. Our aim was to explore patterns of shared strains within families by using molecular typing. Family members of H. pylori-infected 10- to 12-year-old index children identified in a school survey were invited to undergo gastroscopy. Bacterial isolates were typed with random amplified polymorphic DNA and PCR-restriction fragment length polymorphism of the genes ureA-B, glmM, or flaA. The presence or absence of the cag pathogenicity island, a bacterial virulence factor, was determined by PCR. GelCompar II software, supplemented with visual inspection, was used in the cluster analysis. In 39 families, 104 individuals contributed 208 bacterial isolates from the antrum and corpus. A large proportion, 29 of 36 (81%) of the offspring in a sibship, harbored the same strain as at least one sibling. Mother-offspring strain concordance was detected in 10 of 18 (56%) of the families. Of 17 investigated father-offspring relations in eight families, none were strain concordant. Spouses were infected with the same strains in 5 of 23 (22%) of the couples. Different strains in the antrum and corpus were found in 8 of 104 (8%) of the subjects. Our family-based fingerprinting study demonstrates a high proportion of shared strains among siblings. Transmission between spouses seems to be appreciable. The data support mother-child and sib-sib transmission as the primary transmission pathways of H. pylori.

Tracing clonality of Helicobacter pylori infecting family members from analysis of DNA sequences of three housekeeping genes (ureI, atpA and ahpC), deduced amino acid sequences, and pathogenicity-associated markers (cagA and vacA)

Helicobacter pylori, a Gram-negative bacterium, is a causal agent of peptic ulcers and is estimated to infect the gastric mucosa of at least half of the world's population. As primary infections are acquired mainly by household contact, studies on family clusters provide a model for investigating transmission and the natural history of initial infection. Here, sequence typing exploiting genetic variation in core fragments of three key housekeeping loci (ureI, atpA and ahpC) was used to determine clonal descent amongst isolates of ten members of four families in Northern Ireland and a family with three generations in central England. Phylogenetic analysis of each locus for 73 strains of H. pylori from 11 countries indicated high background intraspecific diversity, apart from identical paired isolates from five unrelated patients and strains with identical sequence types (STs) detected in adult members of two families. In several families carrying strains with different STs, evidence of residual clonal descent was detected at one or two loci by comparison of nucleotide and amino acid sequences. Pathogenicity-associated genotypes were heterogeneous with respect to ST and amino acid type. Analysis of these three housekeeping genes provides unique evidence for precise tracing of clonal descent in isolates of H. pylori in family groups.

Helicobacter pylori: resurrection of the cancer link

Helicobacter pylori is one of the most common pathogenic bacterial infections, colonizing an estimated half of all humans. In a subset of individuals, the infection leads to serious gastroduodenal disease such as peptic ulcers and gastric adenocarcinoma. The factors contributing to skewing this, in most cases benign, relationship into disease development are largely unknown. However, factors emanating from the bacterium, host and the environment have been shown to affect the risk for disease, although no factor can be singled out to be most important. The known factors are associated with affecting the risk of disease, and are not absolute. Virulence of H. pylori is affected by the existence and regulation of certain genes present in the bacterial population in a stomach. The effects of H. pylori on gastric cancer development have been challenged and the risk associated with infection with virulent (i.e. Cag PAI positive) H. pylori has likely been underestimated.

Foetal intrauterine growth restrictions with Helicobacter pylori infection

BACKGROUND

Helicobacter pylori infection has been associated with growth restriction in young children.

AIM

To determine whether there is an association between H. pylori infection and intrauterine growth restriction.

METHODS

Four hundred and forty-eight consecutive pregnant women (aged 15-44 years), attending for routine examinations in the third trimester, were enrolled. Clinical, demographic and previous obstetric data, as well as smoking history, were collected. At delivery, the weight, height, gender and status of the neonate were recorded; intrauterine growth restriction was defined if the birth weight was below the 10th percentile according to the gestational age for infants born in Australia.

RESULTS

Eighty-nine (20%) women were seropositive for H. pylori. The prevalence of H. pylori was significantly lower in Caucasians (17%) vs. non-Caucasians (42%, P < 0.0001). There were 34 (7.5%) cases of intrauterine growth restriction (7% Caucasians, 16% Asians, 12% Aborigines and 0% Pacific Islanders). Intrauterine growth restriction was more common in H. pylori-seropositive women than in H. pylori-seronegative women [13.5% vs. 6%; odds ratio (OR) = 2.41; 95% confidence interval (CI), 1.14-5.08; P = 0.018]. A multiple logistic regression model revealed that smoking (OR = 3.55; 95% CI, 1.62-7.79; P = 0.002), maternal height (OR = 0.48; 95% CI, 0.28-0.80; P = 0.005) and H. pylori seropositivity (OR = 2.59; 95% CI, 1.12-5.95; P = 0.025) were all independent risk factors for intrauterine growth restriction.

CONCLUSIONS

H. pylori infection in pregnant women may affect foetal intrauterine growth.

Role of partner's infection in reinfection after Helicobacter pylori eradication

AIM

To evaluate whether the Helicobacter pylori status of the patient's spouse plays a role in reinfection after eradication success, and to assess the possibility of transmission of H. pylori among partners by using molecular methods.

METHODS

We studied prospectively 120 patients in whom H. pylori had been eradicated. Endoscopy with biopsies and a 13C-urea breath test were performed 1 month after completing therapy. The breath test was repeated in all patients at 6 and 12 months. At the 1-year follow-up visit (or before if reinfection occurred), a breath test was also performed on the patient's partner. Samples for the molecular study included gastric biopsies from patients and gastric content obtained by the string test from partners. The heterogeneity of ureC was studied by enzymatic digestion with MseI and HhaI enzymes of a polymerase chain reaction (PCR) product of 1179 bp belonging to the ureC gene, and different band patterns were generated after electrophoresis.

RESULTS

Four reinfections were diagnosed at 6 months, and four were diagnosed from 6 to 12 months (incidence 6.8% per patient-year). Seven of eight (87%) of the reinfected patients' spouses were infected, but H. pylori infection of spouses was also frequent (76%) among non-reinfected patients. In the multivariate analysis, age of the patient (odds ratio [OR] 0.93, 95% confidence interval [CI] 0.87 to 0.99, P < 0.05), delta(13)CO(2) value after therapy (OR 2.51, 95% CI 1.14 to 5, P < 0.05), and therapy regimen (OR 6.23, 95% CI 1.25 to 31, P < 0.05) were the only variables that correlated with H. pylori recurrence. However, family variables (H. pylori status of spouse, breath test value of spouse, length of time couple had lived together, number of children living at home, household density) did not correlate with recurrences. Thus, the OR for the H. pylori status of spouse (adjusted by age, delta(13)CO(2) and therapy) was 2.93 (95% CI 0.29 to 29, P > 0.05). H. pylori recurrence occurred in seven of 92 (7.6%) patients when the spouse was infected (95% CI 3.7% to 15%), and in one of 28 (3.6%) patients when the spouse was H. pylori-negative (95% CI 0.6% to 18%) (P > 0.05; however, the power of this comparison was < 20%). Therefore, even if the spouse was infected, 92.4% of patients will remain uninfected 1 year after H. pylori eradication. Three reinfected patients (at 1 year) and their partners (also infected) agreed to have the endoscopy and string test performed, respectively. The molecular study revealed that H. pylori strains involved were different in all cases.

CONCLUSION

Recurrence of H. pylori infection seems to be relatively infrequent, even if the patient's spouse is H. pylori-positive. The molecular study demonstrated that the strains in reinfected patients and their partners are different, suggesting that the patient's partner does not act as a reservoir for H. pylori reinfection.

Epidemiology of Helicobacter pylori and peptic ulcer in India

BACKGROUND

There is a wide variation in the prevalence of peptic ulcer in India both before and since the use of endoscopy. We studied the prevalence of peptic ulcer disease in a community in northern India and its relationship with Helicobacter pylori infection.

METHODS

A house-to-house survey of residents aged 15 years or above in a sub-sector of Chandigarh was performed as part of a pilot survey. Subsequently, the study randomly covered all sectors of Chandigarh and we screened 2649 persons. A questionnaire was administered to each subject by trained staff. All individuals with history of peptic ulcer/dyspepsia and an equal number of asymptomatic individuals were asked to attend the outpatient department of the Institute. Diagnosis of peptic ulcer was based on endoscopy or history of previous ulcer surgery.

RESULTS

Two hundred and fifty-four individuals attended the outpatient department at the Institute and 147 underwent endoscopy, biopsy for histology and rapid urease test, and blood was collected for H. pylori serology. There were 80 symptomatic and 67 asymptomatic individuals. Helicobacter pylori was positive in 38 (56.7%) asymptomatic and 49 (61.3%) symptomatic individuals (P > 0.05). The point prevalence of active peptic ulcer was 3.4% and the lifetime prevalence was 8.8%. The duodenal-to-gastric ulcer ratio was 12:1. Helicobacter pylori was present in 11/13 (84.6%) subjects with peptic ulcer. Peptic ulcer was more common in elderly and dyspeptic individuals and there was no effect of sex or socioeconomic status. Helicobacter pylori was associated with age only and did not depend on sex, socioeconomic status or dyspepsia. Of the 38 asymptomatic persons having H. pylori infection, none had active peptic ulcer.

CONCLUSIONS

This study demonstrates frequent occurrence of peptic ulcer and H. pylori in this part of the country. Peptic ulcer was more prevalent in the elderly and dyspeptic subjects. Helicobacter pylori was not associated with dyspepsia, and was more prevalent in elderly subjects. There was a low prevalence of peptic ulcer in asymptomatic H. pylori-infected persons in this community.

Helicobacter pylori infection transmitted sexually via oral-genital contact: a hypothetical model

OBJECTIVES

To postulate that Helicobacter pylori infection may be transmitted sexually, using the human female vagina as a reservoir for transmission.

METHODS

A literature search was performed using Medline, Embase, Biological Abstracts, and Currents Contents (January 1983 to August 2000). Relevant keywords were used and additional manual searches were made using the reference lists from the selected articles to retrieve other papers relevant to the topic.

CONCLUSIONS

Helicobacter pylori infection could be transmitted sexually with the vagina acting as a potential temporary/permanent reservoir given the right environmental conditions.