Elevated risk of Helicobacter pylori infection in submarine crews

The association between submarine service and multimorbidity: a cross-sectional study of Korean naval personnel

OBJECTIVE

We aimed to estimate the prevalence of multimorbidity (≥2 chronic health problems) among Korean submariners and to evaluate the association between submarine service and multimorbidity and disease burden.

STUDY DESIGN AND SETTING

This cross-sectional study included 590 naval personnel who visited a Korean primary care clinic during 2014-2015. Data regarding general characteristics and morbidities were collected from medical records, and disease burden was assessed using the Cumulative Illness Rating Scale (CIRS). Multiple logistic regression analysis was used to evaluate the association between submarine service and multimorbidity and disease burden.

RESULTS

The prevalence of multimorbidity was 11.7% among 180 non-submariners and 32.2% among 410 submariners. The prevalence of multimorbidity and the CIRS scores gradually increased with age. Submarine service was associated with higher risk of multimorbidity and disease burden compared with non-submarine service even after adjusting for age, alcohol consumption, smoking status and naval rank. However, a dose-response relationship was not evident between the duration of submarine service and the risk of multimorbidity as well as high disease burden.

CONCLUSIONS

Submarine service was significantly associated with a higher risk of multimorbidity and greater disease burden than non-submarine service. This finding suggests that multidimensional and holistic healthcare approaches are needed for submariners.

Helicobacter pylori colonization critically depends on postprandial gastric conditions

The risk of Helicobacter pylori infection is highest in childhood, but the colonization process of the stomach mucosa is poorly understood. We used anesthetized Mongolian gerbils to study the initial stages of H. pylori colonization. Prandial and postprandial gastric conditions characteristic of humans of different ages were simulated. The fraction of bacteria that reached the deep mucus layer varied strongly with the modelled postprandial conditions. Colonization success was weak with fast gastric reacidification typical of adults. The efficiency of deep mucus entry was also low with a slow pH decrease as seen in pH profiles simulating the situation in babies. Initial colonization was most efficient under conditions simulating the postprandial reacidification and pepsin activation profiles in young children. In conclusion, initial H. pylori colonization depends on age-related gastric physiology, providing evidence from an in vivo infection model that suggests an explanation why the bacterium is predominantly acquired in early childhood.

Apparent incidence of Helicobacter pylori in adulthood: to what extent do new infections reflect misclassification?

BACKGROUND

Helicobacter pylori infection is a key risk factor for a variety of gastrointestinal diseases. About half of the world population is infected. Most infections are acquired early in childhood, but the occurrence of new infections among adults has also been suggested.

METHODS

We review epidemiological studies providing estimates of incidence of H. pylori infection among adults and evaluate to what extent incidence estimates might have been affected by measurement error of infection status.

RESULTS

Thirty-two studies could be included in the review. Annual incidence was lower than 1.0 % in 17 studies; no correlation between length of follow-up and cumulative incidence was observed. Apparent cumulative incidences of the magnitudes observed in most studies would be expected, because of less than perfect sensitivity and specificity of the diagnostic tests, even in the absence of any true new infections. CONCLUSION/IMPACT: Apparent incidence rates of H. pylori infection among adults in Western populations should be interpreted with utmost caution.

Biofilms in drinking water systems: a possible reservoir for Helicobacter pylori

A laboratory model system was utilised to investigate the persistence of Helicobacter pylori in mixed-species heterotrophic biofilms. A single-stage continuous culture vessel was linked to a modified-Robbins device (mRD) incorporating removable stainless steel coupons. The system was innoculated with H. pylori (NCTC 11637) and the fate of the organism monitored by polymerase chain reaction (PCR) analysis. Helicobacter pylori was detected in biofilm material for a period of up to 192 h. Theoretical washout would have occurred at around 48 h thus detection of H. pylori for a prolonged period after theoretical washout suggested that the organism possessed the ability to persist in the mixed-species heterotrophic biofilm. Preliminary studies using heat-inactivated H. pylori showed that the organism was not detected in biofilm material at any time post-challenge suggesting that the persistence of H. pylori in such material was a phenomenon requiring the organism to be in a viable state. Further investigations to assess the biological basis for the association of H. pylori with drinking water biofilms and the risk that this may pose to public health are being undertaken.

Review article: 'true' re-infection of Helicobacter pylori after successful eradication--worldwide annual rates, risk factors and clinical implications

BACKGROUND

The incidence of 'true' re-infection with Helicobacter pylori after successful eradication remains uncertain.

AIM

To determine the worldwide rates, risk factors and clinical implications of 'true' re-infection of Helicobacter pylori. 'True' re-infection of H. pylori is defined as the situation where tests for H. pylori infection, which were negative for 12 months after eradication, become positive again at a later stage.

RESULTS

Thirty six studies were identified through a literature search to be able to produce annual rates of 'true' re-infection, and data from 33 original articles were considered reliable and adequate in the further review. Generally, the reported rates varied from 0% to 23.4% in adults and from 1.9% to 9.6% in children. Most studies from developed countries reported rates of less than 1%, whereas relatively higher rates were reported in most of the developing countries. Small sample sizes included in the studies appeared to be associated with increased re-infection rates. Interfamilial transmission is the major cause of re-infection, although iatrogenic re-infection through contaminated endoscopic equipment has been reported.

CONCLUSION

Helicobacter pylori re-infection is not a concern in a clinical setting, especially in the developed world; however, caution must be exercised in most developing countries.

Are endoscopy nurses at risk of infection with Helicobacter pylori from their work?

BACKGROUND

In response to studies suggesting risk of occupational transmission of Helicobacter pylori (HP) to endoscopy staff, this cross-sectional study of seroprevalence to HP in gastroscopy nurses working in West of Scotland hospitals (an area of high endemicity of HP infection) was performed to determine if they were at excess risk relative to peers working in surgical specialities but without gastroscopy exposure. The study aimed to fulfil employer's duties to carry out a suitable risk assessment required by health and safety legislation.

METHOD

This cross-sectional study compares the seroprevalence of HP in gastroscopy nurses and comparators drawn from orthopaedic and trauma units in 10 hospitals during 1998. A directly administered questionnaire collated exposure information on occupational and non-occupational risk factors for infection. Venepuncture was performed for latex agglutination test for IgG to HP. Confounding by socio-economic factors was controlled for by multivariate analysis.

RESULTS

Of the 222 participants, 74 were endoscopy staff (84% response) and 148 (59%) were comparators. Of these, 32.4% of gastroscopy and 33% of comparators were seropositive for HP (OR 0.97, P > 0.9, 95% CI 0.5-1.8). No association was found between gastroscopy exposure variables (frequency, years) or exposure to all endoscopy procedures and HP. Significant associations were found for age, childhood deprivation and greater number of siblings.

CONCLUSION

No excess HP infection was found in gastroscopy nurses. Duties imposed by the health and safety legislation appear discharged by normal infection control procedures. Socio-economic factors are key determinants of HP status.

Prevalence of Helicobacter pylori in United States Navy submarine crews

Helicobacter pylori prevalence is elevated in German submarine crews and in United States Navy (USN) surface fleet personnel, but H. pylori prevalence in USN submariners was unknown. The goal of the study was to determine the prevalence of H. pylori in the crews of USN nuclear submarines compared to other military personnel and to the general US population. The presence of H. pylori IgG antibodies was determined in serum samples using a commercial ELISA. Only 47 out of 451 submariners (9.4%) were H. pylori positive, which is similar to that of the US general population with a similar level of education. In contrast, H. pylori prevalence is significantly higher in US Army recruits (26%), USN surface fleet personnel (25%), and German diesel submariners (38%). These data demonstrate that submarine service (and by inference activity requiring isolation and close contact, per se) is not a risk factor for H. pylori infection.

Does hospital work constitute a risk factor for Helicobacter pylori infection?

The aim of this study was to assess whether clinical work constitutes a risk factor for Helicobacter pylori infection among employees in hospitals. The prevalence of H. pylori infection was analysed in 249 individuals employed in a university teaching hospital according to three categories of hospital workers: (A) personnel from gastrointestinal endoscopy units (N=92); (B) personnel from other hospital units with direct patient contact (N=105); and (C) staff from laboratories and other units with no direct patient contact (N=52). Stool samples from each subject were examined with a validated enzyme-linked immunosorbent assay for the presence of H. pylori antigens. A questionnaire inquiring about sociodemographic and occupational characteristics was completed by each participant. The prevalence of H. pylori infection was 37.0% in group A, 35.2% in group B and 19.2% in group C (P<0.05). Among the different healthcare categories, nurses had a significant higher prevalence of H. pylori infection (P<0.01). No significant association was found between the length of employment or exposure to oral and faecal secretions, and H. pylori infection. Hospital work involving direct patient contact seems to constitute a major risk factor for H. pylori infection compared with hospital work not involving direct patient contact.

Helicobacter pylori infection in rural China: demographic, lifestyle and environmental factors

BACKGROUND

Although Helicobacter pylori is one of the most common human bacterial infections worldwide, its mode of transmission is unclear.

METHODS

To investigate possible associations between H. pylori infection and demographic, lifestyle, and environmental factors in a rural Chinese population, a cross-sectional survey was administered to 3288 adults (1994 seropositive, 1019 seronegative, 275 indeterminate) from 13 villages in Linqu County, Shandong Province, China.

RESULTS

Helicobacter pylori prevalence was elevated for: infrequent handwashing before meals (OR = 1.7, 95% CI: 1.0-3.0), crowding (i.e. sharing a bed with >2 people [OR = 2.3, 95% CI: 1.3-4.2]), washing/bathing in a pond or ditch (OR = 1.5, 95% CI: 1.0-2.4), and medium (OR = 1.6, 95% CI: 1.3-2.0) and low (OR = 2.3, 95% CI: 1.9-2.9) compared to high village education level, and reduced for never being married or divorced (OR = 0.4, 95% CI: 0.2-1.0). There was also a suggestion that source of drinking water, especially water from a shallow village well might be related to H. pylori seropositivity. There was no evidence of an association between H. pylori prevalence and alcohol or tobacco use, raw fruit and vegetable intake, or individual social class measures.

CONCLUSIONS

The results of this study suggest that person-to-person transmission is the most plausible route of H. pylori infection in this rural Chinese population, but waterborne exposures deserve further investigation.

Environmental, medical, behavioural and disability factors associated with Helicobacter pylori infection in adults with intellectual disability

In institutionalized adults with intellectual disability (ID), Helicobacter pylori infection occurs at approximately twice the rate it appears in the general population, and it may be responsible for the twofold higher rates of peptic ulcer disease and gastric cancer in this population. Medical, behavioural and additional environmental factors, as well as level of ID, may be related to the risk of infection with H. pylori. One hundred and sixty-eight adults with ID who were currently, had previously been or had never been institutionalized underwent a biopsychosocial evaluation. This included assessment of: level of ID using the Adaptive Behaviour Scale (ABS) Part I; levels of maladaptive behaviour using the ABS Part II; demographic, medical and environmental factors; as well as H. pylori tests using serology and faecal antigen. The overall rates of past or current infection with H. pylori in institutionalized and previously institutionalized participants were about twice that of the overall group of never-institutionalized participants, i.e. 87% and 79% compared to 44%, respectively (P < 0.001). The rates of H. pylori infection appeared to increase with age in the never-institutionalized group, but were consistently high across all ages in the other groups. The rate of infection was higher in those institutionalized for more than 5 years (95% versus 76%, P=0.02), in those with flatmates with excessive oral secretions (65% versus 21%, P < 0.001) or faecal incontinence (67% versus 27%, P < 0.001), and in those with more chronic illness and medications. All mean domain scores of the ABS Part I (Intellectual Disability) were significantly lower (indicating more severe ID) in the group currently infected with H. pylori compared to their non-infected counterparts. The majority of mean domain scores of the ABS Part II (Behaviour) were also worse, with half of these score differences reaching statistical significance in the currently infected group. The presence of alarm symptoms (e.g. vomiting, weight loss, haematemesis and melena), iron deficiency and body mass index were not significantly different in currently infected subjects. Adults with ID appear to be particularly at risk of infection with H. pylori. Environmental associations with infection include past or current institutionalization, a longer period of institutionalization, living with flatmates with excessive oral secretions and faecal incontinence. Medical associations include chronic disease and more medications, but not alarm symptoms or body mass index. Demographic associations may include increasing age in never-institutionalized adults, but no age effect in currently or previously institutionalized individuals. Psychosocial associations include more severe ID and maladaptive behaviour with current infection.

Familial and community environmental risk factors for Helicobacter pylori infection in children and adolescents

BACKGROUND

The aim of the study was to identify familial and community environmental risk factors associated with Helicobacter pylori infection in a pediatric population.

METHODS

Children requiring diagnostic upper endoscopy were included in the study during a 2-year period. During endoscopy, five gastric biopsies were performed for the histologic or bacteriologic diagnosis, or both, of H. pylori infection. Epidemiologic data collected by a questionnaire were analyzed using the chi-square test or Fisher test and stepwise logistic regression.

RESULTS

The authors included 436 patients (242 boys), aged 2 days to 17.9 years (median, 2.7 years). H. pylori prevalence was 7.3%. Univariate analysis found H. pylori was more common in older patients (P < 0.00001), in children who had at least one parent born in a developing country (P < 0.02) or with a low socioeconomic status (P < 0.02), and in those living in crowded conditions (P < 0.02). Children whose mother worked at home were more frequently infected than children whose mother worked outside the home (P < 0.02). Attendance at nursery or school before the age of 6 years was not associated with infection. Logistic regression showed a strong association with H. pylori only for age and number of persons at home.

CONCLUSIONS

The source of H. pylori is intrafamilial rather than from a community, such as nursery and school attended at a young age. The number of persons in the home influences the infection status of children but not by the presence of the mother in home. These data suggest that H. pylori infection transmission occurs from siblings or the father rather than from mother.

Review article: the transmission of Helicobacter pylori from stomach to stomach

The mode of transmission of Helicobacter pylori is largely unknown and is a matter of circumstantial evidence and speculation rather than fact. However, the principle evidence is of two sorts: the epidemiological data, providing evidence of possible risk factors associated with transmission, and the identification of potential sources from which H. pylori could be acquired. Evidence exists for several potential sources of infection and several possible modes of transmission, and it is feasible that the transmission of H. pylori varies according to the cultural and demographic circumstances. However, the most likely recognized source for H. pylori is the human stomach, although it is not known by what route the organism is transmitted to the stomach. Evidence suggests close personal contact is important and that acquisition occurs mainly in childhood. This article reviews the evidence for the source of infection and the route of transmission of H. pylori.

Prevalence of and risk factors for Helicobacter pylori infection among healthcare workers at a teaching hospital in Rome: the Catholic University Epidemiological Study

OBJECTIVES

To evaluate the prevalence of and the risk factors for Helicobacter pylori in a population of medical and non-medical workers at a teaching hospital in Rome, Italy.

DESIGN

A cross-sectional study.

METHODS

From January to October 1998, 655 subjects (65% of the total population) underwent a 13C-urea breath test to assess H. pylori infection. Subjects completed a questionnaire concerning sociodemographic characteristics, work departments and history of some gastrointestinal symptoms. Differences in means and proportions were evaluated and independent predictors of H. pylori infection status were assessed by multiple logistic regression analysis.

RESULTS

Forty percent of the subjects were found to be H. pylori infected. The mean age of positive subjects was significantly higher than that of negative ones (38 +/- 14 versus 34 +/- 12 years; P < 0.01). No significant difference was found between males and females concerning the infection status (40.2% males versus 39.9% females). Lower years of father's education [odds ratio (OR), 3.1; 95% confidence interval (CI), 1.9-5.1] and age older than 35 years (OR, 2.0; 95% CI, 1.3-3.1) were the only independent predictors of the likelihood of H. pylori positivity. Prevalence of gastrointestinal symptoms was similar in infected and uninfected subjects. Physicians were significantly less infected than nurses and auxiliary personnel (26% versus 47% versus 55%, respectively); however, a loss of association was observed after adjustment by multiple logistic regression (OR, 1.8; 95% CI, 0.9-3.7). In all groups, some specific departments appear to be associated with a higher infection status.

CONCLUSIONS

Among healthcare workers, H. pylori infection was associated with specific sociodemographic characteristics, such as age and level of father's education. The prevalence of H. pylori infection was not associated with different professional categories. However, some specific departments seem to increase infection risk.

Recent developments in the epidemiology of Helicobacter pylori

Prevalence determinations have been performed around the world, and regardless of how exotic a location, H. pylori is found in a substantial proportion of the population. H. pylori remains among the most universal of infections. Understanding of some features of infection has changed. Infection can be gained and lost at rates higher than previously realized. Oral-oral and oral-fecal transmission account for most, if not nearly all, cases of infection. H. pylori infection has declined rapidly in developed countries, which probably has contributed to declines in duodenal ulcer disease and gastric cancer. The full health implications of the potential elimination of infection are unknown.

Detection of "Candidatus Helicobacter suis" in gastric samples of pigs by PCR: comparison with other invasive diagnostic techniques

Recently, a new 16S ribosomal DNA-based PCR assay was developed for the specific detection of "Candidatus Helicobacter suis" (former "Gastrospirillum suis") in porcine gastric samples. In the present study, this PCR assay was compared to three other invasive diagnostic methods (rapid urease test, immunohistochemistry, histologic analysis by Giemsa staining). Antral stomach samples from 200 slaughterhouse pigs from Belgium and The Netherlands were examined. Bacterial presence was determined in 77% (154 of 200) of the samples by PCR in combination with Southern blot hybridization, 56% (111 of 200) of the samples by immunohistochemistry, 61% (122 of 200) of the samples by urease testing (20 h postinoculation [p.i.]), 36% (71 of 200) of the samples by urease testing (3 h p.i.), and 33% (65 of 200) of the samples by Giemsa staining. The intrinsic specificity of the PCR assay was assessed by Southern blot analysis with an "Candidatus H. suis"-specific probe and sequencing of PCR products. Interassay sensitivity and specificity values were assessed for each test by pairwise comparisons between tests. Agreement between tests was evaluated by calculating Cohen's kappa coefficient. From that analysis, the PCR assay was considered the most reliable benchmark. Microscopic detection of immunohistochemically labeled or Giemsa-stained "Candidatus H. suis" cells in stomach sections proved to be highly specific (100%) but relatively insensitive (72 and 42%, respectively) compared to the PCR assay. A longer incubation time of the urease test improved its sensitivity considerably (74 versus 55%) but was accompanied by a loss of specificity (72 versus 93%). In conclusion, we found the "Candidatus H. suis"-specific PCR assay to be a sensitive and reliable diagnostic method for the detection of "Candidatus H. suis" in the stomachs of pigs and could prove to be a valuable tool for further epidemiological studies both for "Candidatus H. suis"- and for "Helicobacter heilmannii" type 1-related research.

Host determinants of Helicobacter pylori infection and its clinical outcome

Greater than one-half of the world's population harbors Helicobacter pylori. The majority of infected individuals, however, remain asymptomatic, with only 10% to 20% developing diseases, including peptic ulcer disease, gastric cancer, and gastric mucosa-associated lymphoid tissue lymphoma. This article reviews host factors that may predispose an individual to both the acquisition of H. pylori infection and subsequent clinical outcome. Individuals with specific blood group antigens and human leukocyte antigen genotypes may be more susceptible to H. pylori infection. Additional factors, such as the age of acquisition, the host immune response, the site of infection, acid secretion, and interactions with nonhost factors (including bacterial virulence factors and environmental influences) may play a role in determining clinical outcome. Further investigation is required to clarify the mechanisms by which these interactions occur and, more critically, to determine their relative importance. This knowledge will enable the identification of individuals at risk of developing clinical disease with H. pylori infection.

Helicobacter pylori infection in indigenous families of Central America: serostatus and oral and fingernail carriage

Helicobacter pylori infection remains one of the most common in humans, but the route of transmission of the bacterium is still uncertain. This study was designed to elucidate possible sources of infection in an isolated, rural population in Guatemala. A total of 242 subjects in family units participated in the study. A medical history, including a history of dyspepsia, was taken by a physician and immunoglobulin G antibodies to H. pylori were detected with the QuickVue (Quidel, San Diego, Calif.) onsite serology test. Overall, 58% of subjects were seropositive, with a positive relationship between mother and child (P = 0.02) and a positive correlation between the serostatuses of siblings (intraclass correlation coefficient = 0.63). There was no association between serostatus and gastric symptoms. Oral H. pylori was detected from periodontal pockets of various depths and the dorsum of the tongue by nested PCR. Eighty-seven percent of subjects had at least one oral site positive for H. pylori, with the majority of subjects having multiple positive sites. There was no association between periodontal pocket depth and the detection of H. pylori. Nested PCR was also used to detect H. pylori from beneath the nail of the index finger of each subject's dominant hand. Overall, 58% of subjects had a positive fingernail result, with a significant positive relationship between fingernail and tongue positivity (P = 0.002). In conclusion, the results of this study suggest that oral carriage of H. pylori may play a role in the transmission of infection and that the hand may be instrumental in transmission.

Seroprevalence of Helicobacter pylori and length of stay in a nursing home

BACKGROUND

Helicobacter pylori infection appears to be contracted mainly in childhood, and it is associated with disadvantaged socioeconomic conditions, overcrowding, and living in institutions. In this study we determined the seroprevalence of H. pylori among elderly patients (age > or = 70 years) admitted to a major medical center in Israel, and studied the relationship between seroprevalence of H. pylori and the duration of stay in a nursing home prior to the admission.

PATIENTS AND METHODS

Whole blood from 182 consecutive patients hospitalized at the Rabin Medical Center was tested for the presence of anti-H. pylori IgG using Helisal Rapid Blood Test kit (Cortecs Diagnostics). Multivariate logistic regression analysis was used to study the relation between H. pylori seropositivity and possible predictive factors such as age, gender and duration of stay in a nursing home.

RESULTS

Of the 182 patients included in the study, 80 (44%) were living in nursing homes (NH) and 102 (56%) were living in their own homes (H) prior to admission. Subjects that stayed in nursing homes for more than 15 months were significantly more likely to be seropositive than subjects with a shorter duration of stay (84% and 63% respectively, p = 0.03). Using a multivariate logistic regression analysis on both the NH group and the whole group, seropositivity was found to be significantly associated with duration of stay in a nursing home (p = 0.03 and p = 0.01 respectively). Seropositivity was not associated with age in either group.

CONCLUSIONS

Living in a nursing home is associated with increased risk for H. pylori infection in the elderly. There is a strong correlation between the duration of stay in a nursing home and the prevalence of H. pylori infection.

Helicobacter pylori in an institution for disabled children in Hong Kong

Anti-Helicobacter pylori antibodies were determined in 157 institutionalised Cantonese children, mean age 9.5 +/- 3.9 (SD) years, with profound neurodevelopmental disabilities. Eighty-seven (55.4%) were H. pylori seropositive compared with four of 50 (8%, P > 0.0002) of an age-matched control group, mean age 7.2 +/- 4.3 (SD) years. Eight of 15 seropositive children with a recent history of upper gastrointestinal bleeding underwent endoscopy and in all cases gastric infection with H.pylori was confirmed. Anthropometric data from institutionalised children revealed marked malnutrition but showed no significant difference between seropositive and seronegative children. Disabled children receiving long-term residential care in Hong Kong are confirmed to be at increased risk of H.pylori infection.

Is Helicobacter pylori transmitted from cats to humans?

BACKGROUND

Subsequent to the isolation of Helicobacter pylori from domestic cats, it has been suggested that the organism might be transmitted from cats to humans. This hypothesis has already gained considerable media attention.

MATERIALS AND METHODS

In a previous study of risk factors for H. pylori infection, 447 factory workers from Stoke on Trent in the UK had provided blood samples for H. pylori serological workup. They had also completed a detailed questionnaire concerning their living conditions, including the possession of any household pets, in childhood. Logistic regression was used to assess the association between cat ownership in childhood and H. pylori seropositivity.

RESULTS

After adjustment for potential confounders, it was found that subjects who had owned a pet as a child were slightly more likely to be H. pylori seropositive than subjects who had not. There was, however, no difference between subjects who had owned a cat and those with other pets.

CONCLUSIONS

These data do not support the hypothesis that H. pylori infection might be transmitted from cats to humans.

Prevention of Helicobacter pylori infection

A gastroenterologist, treating a patient with H. pylori, must decide whether the unit of treatment is only the ill individual, or the family, perhaps including close contacts. If it is the family and close contacts, is it all family members and contacts, or are there some ages, relationships, or clinical characteristics that increase the risk of transmission to the patient after successful treatment of their infection? In preventing reinfection, the available data suggest: the natural infectious dose has not been determined infection may occur from oral or faecal shedding children are more infectious than adults socio-economic factors are important in any comparison of infection rates food and water seem unlikely vehicles in the developed world travel in the third world may increase risk of infection seropositivity in adults predominantly reflects exposure in childhood infection is frequently with more than one strain reinfections are not more frequent in families with other members infected reinfections are infrequent with strains different from the original strain reinfection might be more frequent in developing countries no need for all family members to be treated to reduce reinfection rates. In considering vaccine, the available data suggest: breast milk IgA can reduce infection rate antibodies induced by vaccine may reduce infection in animals late benefit of childhood vaccination in developed countries probable early benefit of childhood vaccination in developing countries vaccination of already infected adults would have cost-benefit.

Transmission and acquisition of Helicobacter pylori infection: evidences and hypothesis

The role of Helicobacter pylori in gastroduodenal diseases has been established, but many ecological and epidemiological features remain unclear. Although H pylori infection is one of the most common infections in the world, the mode of transmission remains unknown. Uncommon extra-endoscopic isolation raises obstacles to a good understanding of epidemiological patterns, and no rational basis exists for a prophylaxis strategy. This work reviews the data on the reservoir of the bacteria and its ecological niche, the method of excretion from the site of infection and the possible circumstances of acquisition. Many features are completely unknown or still controversial, and interpretation is often speculative. At the present time, it can be assumed that the most likely mode of spread would be from saliva in childhood. However, further works are required to establish, whether or not, fecal transmission co-occurs in low hygiene conditions.

Cytomegalovirus (CMV) and Helicobacter pylori (HP) found in oral mucosal ulcers

The possible involvement of Cytomegalovirus (CMV) and Helicobacter pylori (HP) in oral mucosal ulcers is suggested by their role in the development of ulceration at other mucosal sites of the gastrointestinal tract. A series of 29 incisional biopsies from 29 consecutive and apparently immunocompetent patients attending the clinic for oral ulceration were examined by routine histopathology as well as by in situ hybridisation (ISH) with biotinylated CMV and HP DNA probes. In 14/29 biopsies, Giemsa staining disclosed spiral bacteria. Six (20.7%) of these 14 Giemsa-positive samples showed HP DNA on ISH and 3 ulcers (10.3%) contained CMV DNA. In none of the specimens were CMV and HP detected simultaneously. Two of the ulcers containing CMV DNA were found on the labial mucosa and one on the posterior palatal mucosa, whereas all HP DNA-positive ulcers were located on the buccal mucosa. The results indicate that CMV and HP DNA can be found in separate oral mucosal ulcers in apparently immunocompetent adults.

Helicobacter pylori

Helicobacter pylori is an important cause of chronic active gastritis and is strongly associated with peptic ulcer disease and gastric cancer. H. pylori colonizes the surface of the gastric epithelium with production of a number of factors, resulting in inflammation and an altered mucosa. H. pylori infection occurs world-wide and the mode of transmission most likely is from human to human via the fecal-oral and/or the oral-oral route. Treatment and, in the future, prevention of this infection may result in a marked diminution of upper gastrointestinal tract disease.

Helicobacter pylori seroepidemiology in risk groups

Helicobacter pylori is associated with peptic ulcer and chronic active gastritis. The response to infection can be determined by measuring serum titers of anti-H. pylori antibodies. We compared antibody titers in 612 serum samples from 570 individuals considered at risk for H. pylori infection, 170 of them are control sera from 110 adults and 60 children with no gastric alterations. The study groups were 93 institutionalized mentally handicapped children, 40 heterosexual couples, 101 HIV-sero-positive patients, 86 patients with chronic renal failure and 40 individuals (20 adults and 20 children) with symptoms associated with gastritis or gastroduodenal ulcer disease. In the adult and child control groups, 33.5% and 11.6% of the individuals had circulating anti-H. pylori antibodies. Significantly more adults (80%) and children (75%) with gastric symptoms had detectable circulating antibody titers. Elevated titers were also found in institutionalized children and in adults with renal failure.

Relation between infection with Helicobacter pylori and living conditions in childhood: evidence for person to person transmission in early life

OBJECTIVES

To relate the prevalence of infection with Helicobacter pylori in adults to their living conditions in childhood to identify risk factors for infection.

DESIGN

Prevalence study of IgG antibodies to H pylori (> 10 micrograms IgG/ml, determined by enzyme linked immunosorbent assay (ELISA)) and reported living conditions and other socioeconomic factors in childhood.

SETTING

Three factories in Stoke on Trent.

SUBJECTS

471 male volunteers aged 18 to 65 years.

MAIN OUTCOME MEASURES

Seroprevalence and variables in childhood.

RESULTS

Seroprevalence of H pylori increased with age (22/74 (29.7%) at < 30 years v 29/46 (63%) at 55-65 years; P < 0.001 for trend) and was related to manual occupation (14/65 (21.5%) for non-manual v 162/406 (39.9%) for manual; P = 0.003). After data were adjusted for age and occupation subjects from large families, whose childhood homes were crowded or who regularly shared a bed in childhood, were significantly more likely to be seropositive (adjusted odds ratio (95% confidence interval) 2.15 (1.41 to 3.30) for crowding and 2.13 (1.38 to 3.30) for sharing a bed), but there was no relation with possession of a bathroom, inside toilet, refrigerator, or household pets in childhood.

CONCLUSIONS

Close person to person contact in childhood is an important determinant of seroprevalence of H pylori in adulthood, suggesting that the infection is transmitted directly from one person to another and may be commonly acquired in early life.

High prevalence of Helicobacter pylori infection in cohabiting children. Epidemiology of a cluster, with special emphasis on molecular typing

Intrafamilial cases of infection with the same strain of Helicobacter pylori (H pylori) have been reported but these clusters were too small to distinguish between person to person spread or coinfection from a common environmental source. To gain more information on the mode of transmission of H pylori, an epidemiological survey with bacterial strain differentiation by restriction endonuclease analysis of chromosomal DNA was carried out in an institution of 117 children with encephalopathy (aged 3.5 to 19 years). All children with antibodies against H pylori had gastroscopy to obtain gastric biopsy specimens. The prevalence of infection (confirmed histologically or microbiologically, or both) was 38% (45/117), and rose to 67% in one of the five sections of the institution. H pylori was isolated in 34/45 cases, and 22 different strains were found of which five strains were present in more than one child. Up to seven children were infected by the same strain, five of them were living in the same section. Analysis of the characteristics of infected children showed the predominant role of living conditions and the period of time cohabiting in this unexpectedly high prevalence of H pylori infection in children living in good sanitary conditions.