Helicobacter pylori genomic microevolution during naturally occurring transmission between adults

The human gastric pathogen Helicobacter pylori is usually acquired during childhood and, in the absence of treatment, chronic infection persists through most of the host's life. However, the frequency and importance of H. pylori transmission between adults is underestimated. Here we sequenced the complete genomes of H. pylori strains that were transmitted between spouses and analysed the genomic changes. Similar to H. pylori from chronic infection, a significantly high proportion of the determined 31 SNPs and 10 recombinant DNA fragments affected genes of the hop family of outer membrane proteins, some of which are known to be adhesins. In addition, changes in a fucosyltransferase gene modified the LPS component of the bacterial cell surface, suggesting strong diversifying selection. In contrast, virulence factor genes were not affected by the genomic changes. We propose a model of the genomic changes that are associated with the transmission and adaptation of H. pylori to a new human host.

Helicobacter and salmonella persistent infection strategies

Some host-adapted bacterial pathogens are capable of causing persistent infections in humans. For example, Helicobacter pylori inhabits the human gastric mucosa and persistence can be lifelong. Salmonella enterica serovar Typhi causes systemic infections that involve colonization of the reticuloendothelial system and some individuals become lifelong carriers. In this review, I compare and contrast the different lifestyles of Helicobacter and Salmonella within the host and the strategies they have evolved to persist in mammalian hosts. Persistently infected carriers serve as the reservoirs for these pathogens, and the carrier state is an essential feature that is required for survival of the bacteria within a restricted host population. Therefore, investigating the chronic carrier state should provide insight into bacterial survival strategies, as well as new therapeutic approaches for treatments.

[Transmission route of H. pylori]

The incidence of Helicobacter pylori (H. pylori) infection is rapidly decreased in Japan. H. pylori infection is mainly acquired in the first 2 years life and the risk of infection declines rapidly after 5 years of age. Person-to-person transmission in the family appears to be the predominant and in the population with low prevalence, several studies showed the infected mother is likely to be the main source of the infection. H. pylori can be detected from vomitus, saliva and cathartic stools and the possibility of source of infection. Waterborne infection is unlikely in the developed countries.

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.

Epidemiological ins and outs of helicobacter pylori: a review

Helicobacter pylori infection is now recognised as a worldwide problem. It is the most common cause of chronic gastritis, and is strongly linked to peptic ulcer disease and gastric cancer. A comprehensive understanding of epidemiological ins and outs of H. pylori infection is very important in solving the patho-physiological enigma and might help in leading towards better management and prognosis of infection. This article presents a review of the literature on the epidemiology of H. pylori infection from 2006 to 2011. The authors used Medical Subject Heading (MeSH) terms 'Helicobacter' with 'epidemiology,' 'transmission' or 'risk factor' to search PubMed database. All relevant studies identified were included. Despite extensive medical advancement, many questions on Helicobacter pylori epidemiology still remain unanswered. Further studies are, therefore, required to gain a better understanding of the transmission pathway of this notorious pathogen.

Helicobacter pylori persistence in children: distinguishing inadequate treatment, resistant organisms, and reinfection

Helicobacter pylori is a worldwide infection that causes chronic gastritis, duodenal ulcers, and malignancy. Transmission of Helicobacter pylori within a family appears to be the predominant mode of contamination. Recurrence of the infection is frequently seen following treatment. Lack of eradication due to either inadequate treatment or resistant bacteria vs. reinfection have been explanations for detection of H. pylori following treatment. In this article we will discuss the concepts of inadequate treatment vs. resistant infection and reinfection as causes of persistent H. pylori infection.

[Helicobacter pylori: routes of transmission of infection (a review of literature)]

The paper reviews the data characterizing the routes of transmission of Helicobacter pylori. Particular emphasis is laid on the water transmission route that has not been long considered to be important despite strong epidemiological evidence that allows it to be regarded as one of the most important routes of transmission of this infection. It describes the most favorable conditions for this microorganism to survive in the water systems, including plumbing, and a possible survival mechanism via biofilm formation and zooplankton symbiosis. The pathogen is able to bind to autochronous microorganisms in the biofilms and to generate itself the latter. It is not inconceivable that this microbe can persist and even multiply within protozoa. Due to the improved analytical studies, there are additional possibilities to detect new pathogenic microorganisms that have not been historically regarded as pollutants. These microorganisms are of interest to community hygiene specialists. The preferred routes of urban and rural transmission of the pathogen may be different, which should be taken into account when elaborating preventive measures.

PCR assay targeting virulence genes of Helicobacter pylori isolated from drinking water and clinical samples in Lahore metropolitan, Pakistan

Helicobacter pylorus is considered for chronic gastritis, gastric ulcers and adenocarcinoma and its high infection rate is observed in overcrowded and lower socioeconomic groups in developing countries. This study was designed to identify the role of drinking water in the transmission and prevalence of H. pylori (HP). Selective HP medium was developed for enrichment and presumptive identification of H. pylori by urease, catalase and species specific 16S rRNA tests. The virulence genes (vacA 's' and 'm' regions and cagA) of H. pylori in 90 out of 225 H. pylori positive drinking water samples were present (40%). Ten out of 18 biopsies (55.55%) and 15 out of 50 vomiting fluids of gastric disease patients (30%) were also positive for virulence genes. Anti-H. pylori antibodies were also detected in 31 out of 50 patients' sera. The presence of virulence genes was also directly confirmed by hybridization studies using non-radioactive DNA probes of 16S rRNA, vacA and cagA genes. The presence of H. pylori in water is due to poor sanitary conditions, improper waste disposal and lack of public health education. PCR-based analysis and colony hybridization can be used for detection of H. pylori in clinical and environmental samples.

Detection of Helicobacter pylori in saliva and esophagus

The route of Helicobacter pylori transmission remains unclear and the currently suggested route is person-to-person transfer by faecal-oral and oral-oral mode. The aim of this study was to verify the presence of H. pylori in esophagus and saliva of humans. Saliva samples, mucosal biopsies from esophagus, gastric antrum and fundus were collected from 19 patients with positive Urea Breath Test (UBT). Gastric biopsies were used for H. pylori colture and antimicrobial susceptibility tests whereas saliva samples were collected to detect H. pylori with a Nested-PCR targeting 16S rRNA gene as well as esophagus biopsies which were also investigated with immunohistochemical staining. Helicobacter pylori was isolated in 18 patients both in gastric antrum and fundus. The molecular analysis, confirmed by comparative sequences evaluation, gave positive results in all saliva and esophageal samples whereas the immunohistochemistry revealed the presence of H. pylori in 15.8% (3/19) of the esophagus samples. Our data suggest that saliva and esophagus may be considered reservoirs for H. pylori in humans and emphasize the need to use more susceptible techniques for H. pylori detection, in particular in over-crowded sites. Identification of the transmission route of H. pylori is crucial in developing an effective plan of surveillance by finding new means of disease management.

Isolation and identification of Helicobacter pylori from drinking water in Basra governorate, Iraq

The mode of the transmission of Helicobacterpylori infection remains poorly understood. A total of 198 samples of drinking water from 22 districts of Basra governorate were collected during the period October 2006 to July 2007. The concentration of residual chlorine was measured and the numbers of total and faecal coliforms were counted. On modified Columbia urea agar, 469 bacterial cultures were obtained, of which 173 isolates were identified. Only 14 isolates were Helicobacter spp., of which 10 were H. pylori (2.0% of the total isolates). These isolates were tested for antibiotic susceptibility as well as ability to tolerate chlorine at 0.5 mg/L. To our knowledge, this is the first report of the occurrence of H. pylori in treated municipal drinking water.

A rigorous small area modelling-study for the Helicobacter pylori epidemiology

This paper presents an investigation into spatial risk differences over small distances for the Helicobacter pylori infection in the city of Leipzig, Germany and two rural districts. A model, using Bayesian inference, was developed that adjusts the risk for individual-specific factors, and for spatial or individual over-dispersion, respectively. Additionally, the model takes into account conditional spatial autocorrelation. We found a significant positive association to the H. pylori infection risk for: "more than three children live in the household" (OR=2.4, p=0.001), "more persons live per sq.m than average" (OR=1.4, p=0.03), "home situated at main road" (OR=1.4, p=0.04) and "using well water" (OR=2.3, p=0.05). A protective effect was identified for "travelled to low prevalence region" (OR=0.4, p<0.0001) and "born in Germany" (OR=0.2, p<0.0001). Three administrative areas with significantly increased spatial risk were identified: one in the rural district and two in the city of Leipzig. The model explained 24.9% of the total deviance. Contrary to expectations, the largest part of deviance of the data was not explained by the identified significant risk factors, but by individual-specific heterogeneities. We conclude that further - so far not discussed - factors influence the risk and the spatial variation of the H.pylori infection. Furthermore, from the results we speculate about a possible impact of long-time air pollution and surface water.

[Is the mother a risk factor for transmission of Helicobacter pylori infection in children between the ages of 6 months and 5 years in Côte d'Ivoire?]

OBJECTIVES

The goals of this study were to determine the prevalence of H. pylori antibodies in children, to establish the relationship between child and mother serostatus, and to identify potential risk factors for contamination.

MATERIAL AND METHODS

A cross-sectional study was conducted over a 3-month period. All children between 6 months and 5 years of age examined in the Pediatrics Department of the University Hospital Center in Yopougon, Côte d'Ivoire were included after obtaining informed consent from their mothers. Testing for H. pylori antibodies using Pylorix (Acon) was performed in both children and mothers. Based on test results, children were divided into two groups, i.e. case group with H. pylori antibodies and control group without H. pylori antibodies. Case and control groups were compared according to the H. pylori status of their mother and several potential lifestyle and environmental factors.

RESULTS

A total of 101 children and 101 mothers were included. The prevalence of H. pylori antibodies was 40.6% in mothers and 24.8% in children. The mean age of children (53% male) was 22.8 +/- 15.6 months (median, 18 months). The mean age of the mothers was 29.6 +/- 5.5 years (range, 19 to 46 years; median, 29 years). Most mothers, i.e., 78.2%, lived in two-parent households but 19% lived in single-parent settings (community or shacks). The number of persons living in the same house ranged from 2 to 20 people (mean, 7.2 +/- 3.8; median, 6 people). Mean monthly household income was 226,188 +/- 161,425 FCFA (range: 30,000 - 750,000 FCFA). In the case group, 80% of children had mothers infected with H. pylori. In the control group, 73.7% of children had non-infected mothers (OR = 11.2, p < 0.001). Median income was less than 150 000 FCA in 76% of families with seropositive children in comparison to 46.1% of families with seronegative children (p = 0.009).

CONCLUSION

This study confirms the early occurrence of H. pylori infection in children. Findings also showed that poor socio-economic condition was a risk factor for infection but the greatest risk factor was living with a mother infected with H. pylori.

Helicobacter pylori infection in mother and infant pairs in Anatolia

BACKGROUND/AIMS

The aim of this prospective study was to determine the seroprevalence rates of Helicobacter pylori in mother and infant pairs and to discuss the possible fecal-oral transmission route of Helicobacter pylori infection in the early years of life.

METHODS

Forty-eight mother-child pairs were followed for 12 months. Helicobacter pylori IgG and hepatitis A virus (HAV) IgG levels were measured in maternal sera, infant sera and breast-milk samples at birth and in breast-milk samples and infant sera at follow-up visits.

RESULTS

At birth, the rate of Helicobacter pylori positivity was 81.25% in breast-milk and 95.8% in maternal and infant sera. Although there was a decrease in seropositivity in both baby sera and breast-milk at the age of nine months, an increase was observed in the 12th month. Hepatitis A virus IgG was measured to show whether Helicobacter pylori and hepatitis A virus use the same transmission routes. Hepatitis A was positive in all infants' sera, in 95.8% of mothers' sera, and in 68.75% of breast-milk samples. Seropositivity rates in infants whose mothers were seropositive for Helicobacter pylori and hepatitis A virus decreased gradually. There was an increase after the 9th month of life.

CONCLUSIONS

Helicobacter pylori seroprevalence rates are high in Anatolia. It is possible that the decrease in breastfeeding with increased introduction of supplemental foods may lead to an increased risk of exposure to Helicobacter pylori.

The association of drinking water quality and sewage disposal with Helicobacter pylori incidence in infants: the potential role of water-borne transmission

The mode of transmission of Helicobacter pylori, a bacterium causing gastric cancer and peptic ulcer disease, is unknown although waterborne transmission is a likely pathway. This study investigated the hypothesis that access to treated water and a sanitary sewerage system reduces the H. pylori incidence rate, using data from 472 participants in a cohort study that followed children in Juarez, Mexico, and El Paso, Texas, from April 1998, with caretaker interviews and the urea breath test for detecting H. pylori infection at target intervals of six months from birth through 24 months of age. The unadjusted hazard ratio comparing bottled/vending machine water to a municipal water supply was 0.71 (95% confidence interval (CI): 0.50, 1.01) and comparing a municipal sewer connection to a septic tank or cesspool, 0.85 (95% CI: 0.60, 1.20). After adjustment for maternal education and country, the hazard ratios decreased slightly to 0.70 (95% confidence interval: 0.49, 1.00) and 0.77 (95% confidence interval: 0.50, 1.21), respectively. These results provide moderate support for potential waterborne transmission of H. pylori.

Gastric tubes as vectors of Helicobacter pylori transmission

Peptic ulcer was a rare disease before 1850. The prevalence of peptic ulcer increased gradually in persons born between 1870 and 1900. A similar decay in opposite direction of the prevalence occurred after the 1960-1970s. Although the pathogenesis of peptic ulcer is readily explained by the Helicobacter pylori infection, the bacterium occurred many thousands years ago and followed the migrations of human populations; consequently, its presence does not explain the increase in peptic ulcer prevalence. Gastric tubes for secretory testing were introduced from 1871 and their use was extended gradually in the then growing departments of gastroenterology, becoming a very popular, though unpleasant method. There is circumstantial evidence from the pre-H. pylori era that gastric/enteral infections could be transmitted though contaminated gastric tubes/electrodes. The author's hypothesis is based on the temporary overlap of the increased peptic ulcer prevalence and the extensive use of gastric secretory testing. The use of contaminated gastric tubes in sick persons harbouring pathogenic strains of the bacterium could have led to the transmission of the infection by gastro-oral route to the patients' ward-mates and on, to their family members: years later, new ulcer or dyspeptic patients may have come from such groups. The current decay in peptic ulcer prevalence could be due to the decreased use of secretory testing and implementation of rigorous disinfection rules.

[Epidemiology of H. pylori infection and exploration of its infection route]

To build up a preventive strategy for H. pylori related diseases including gastric cancer, infection ages and routes are important. Recently, several studies have explored them. In advanced countries, most infections occur under five years of age. Mother to child in some studies and sibling to sibling in others were dominant infection routes. As infection ages and routes depend on countries, studies in Japan are indispensable. Infection in kindergartens, nursery and elementary schools as well as in families should be explored. Based on the findings, a strategy preventing infection to children should be build up to prevention H. pylori related diseases.

[Helicobacter pylori infection in childhood]

Helicobacter pylori (H. pylori) infection is mainly acquired in the first 2 or 3 years and the risk of infection declines rapidly after 5 years of age. In developing countries, acquisition age of the infection is probably lower than in developed countries. In Japan, main transmission route is intrafamilial and mother to children infection is most important. But in developing countries, some reports suggest that extrafamilial infection is more important. The famous paper revealed that H. pylori can be cultivated from vomitus, saliva and cathartic stools and the possibility of source of H. pylori infection. Bed sharing, large number of family members, delayed weaning from a feeding bottle, regurgitated gastric juice in the mother's mouth are reported as risk factors of the infection.

[Epidemiological study on status of Helicobacter pylori in children and teenagers in Wuwei city, Gansu province]

OBJECTIVE

To investigate the prevalence of Helicobacter pylori (Hp) infection among children aged 3 to 18 years old of Wuwei city, Gansu province.

METHODS

The study was based upon a personal questionnaire and a determination of Hp antigen using the Hp stool antigen test (HpSA) method. A total of 938 subjects and 96 families were selected in Wuwei city. Eighty children and teenagers with a definite positive Hp stool antigen test were examined by serum Western blotting method.

RESULTS

The prevalence of Hp was 72.3% (678/938) with no age difference. Prevalence of Hp infection was correlated with type of dwelling, occupation of parents, drinking water source, kindergarten attendance, consumption of raw vegetables, a poor oral hygiene and breast feeding etc. According to the multivariate analysis, drinking water source, kindergarten attendance and consumption of raw vegetables were most strongly associated with prevalence of Hp in children and adolescents. The infection rate of parents whose children were infected with Hp was higher than that of those whose children were not infected [82.3% (121/147) vs 47.4% (18/38), chi(2) = 19.736, P < 0.05]. The antibody responses of 57 samples (71.3%) from 80 children were of type I Hp and 23 samples (28.7%) type II.

CONCLUSIONS

Hp infective rate is high in Wuwei city. The data support maternal-child and sibling-sibling transmission as the primary transmission routes of Hp. The results of serological analysis confirm that the majority of Wuwei Hp infection is of type I.

Transmission of Helicobacter pylori and the role of water and biofilms

Documented evidence relating to the survival of Helicobacter pylori outside the gastric niche is extremely limited. To date the primary transmission routes of H. pylori have yet to be confirmed and when this is achieved preventive infection control measures can be implemented to reduce and ultimately prevent human infection from this pathogen. There is mounting evidence which suggests that the prevalence of H. pylori infection has a strong correlation with access to clean water, suggesting a transmission route to the host. However, there are no established culture methods for the detection of viable H. pylori in the environment, in particular drinking water supplies, preventing the development of true epidemiological and risk assessments. The aim of this review is to highlight the available data to date that suggests drinking water and possible survival in biofilms as a probable transmission mode for H. pylori.

Epidemiology of Helicobacter pylori infection in Malaysia--observations in a multiracial Asian population

Observations of racial differences in the prevalence of Helicobacter pylori in Malaysia have been intriguing. The Indians and Chinese consistently have a higher prevalence compared to the Malays. The racial cohort theory has been proposed to explain these differences where transmission and perpetuation of infection takes place within a racial group rather than between races, races being separate owing to the low rate of interracial marriages. Studies have demonstrated distinctive bacterial strains between races. Phylogenetic studies have shown that H. pylori isolates amongst Chinese and Indians are distinctive while Malays have Indian and other strains suggesting a more recent acquisition of the bacterium from Indians. H. pylori is recognized as the major causative factor in peptic ulcer disease and gastric cancer. Despite the high prevalence of H. pylori, Indians have a relatively low prevalence of peptic ulcer disease and a low incidence of gastric cancer. This paradox with regards to gastric cancer has been termed the "Indian enigma". Bacterial strain differences between races may be putative but this observation may also indicate gastroprotective environmental factors or a lower genetic susceptibility to develop cancer in the Indians.

Evaluation of eating habits in dyspeptic patients with or without Helicobacter pylori infection

BACKGROUND

The prevalence of Helicobacter pylori infection varies in different societies and geographical locations. This is attributed to socioeconomic status, life style, family density and other factors. There is also a possibility of an association between eating habits and the prevalence of H. pylori infection.

AIM

In this study, we examine the association between H. pylori infection and particular eating habits such as sharing plates, glasses and spoons.

METHODS

This cross-sectional study was performed via a questionnaire-based evaluation of all patients with dyspepsia who underwent endoscopic assessment. Data including demographic information, endoscopic findings, H. pylori status and sharing of dishes within families were recorded. Individuals with a history of 3-day antibiotic treatment in the past month, or use of proton pump inhibitors in the past two weeks, or regular use of H2-blockers during the past week were excluded. The H. pylori status was determined using the rapid urease test.

RESULTS

Of the 225 participants who had filled in the questionnaire, 204 were eligible; 92 were male (45.1%) and 112 female (54.9%) with 22% younger than 30 years of age, 49% between 30 and 50 years and 29% older than 50. In families where common dishes were used, the prevalence of H. pylori infection was significantly higher. (77% vs. 53%, p = 0.001) Factors such as age, sex, and education proved to be irrelevant.

CONCLUSION

The results suggest a strong link between H. pylori infection and eating habits, thereby raising the possibility that modification of these habits might limit H. pylori infection.

[Helicobacter pylori 25 years after (1983 -2008): epidemiology, microbiology, pathogenics, diagnostics and treatment]

EPIDEMIOLOGY

People have been infected by this bacteria 58,000 years ago. Prevalence of infection varies in different nation. In developing countries infection is acquired in early childhood. The forms of infection are/fecal-oral, oral-oral an gastro oral. In Perú we found same prevalence in the coast, jungle and sierra and described that water is one of the ways of infection.MICROBIOLOGY: Three strains predominant in Spanish, Asiatic and people from India have been identified. DNA has 1.65 million bases. Different factors of virulence, enzymes and toxins have also been described.

PATHOGENESIS

Inflamatory response; neutrophiles, lymphocytes T and B, plasma cells, macrophages.METHODS OF DIAGNOSIS: Invasive and non invasive procedures.

THERAPY

Different treatment schemes are described: 1st, 2nd, 3rd lines, rescue therapies. Secondary reactions, alternative schemes, recurrence, reinfection and experience in Perú are also described.