Endoscopy is not a risk factor for Helicobacter pylori infection--but medical practice is

Transmission routes and patterns of helicobacter pylori

BACKGROUND AND OBJECTIVE

Helicobacter pylori (H. pylori), a gram-negative bacterium that colonizes the stomach, can cause chronic gastritis and peptic ulcers, as well as gastric cancer as a Class I carcinogen. However, the modes of H. pylori transmission are not clear. This review aims to clarify the transmission routes and patterns of H. pylori and identify efficacious prevention measures.

METHODS

Studies of H. pylori transmission were identified using PubMed, the Web of Science, and Cochrane Central; the retrieval deadline was October 2022.

RESULTS

The transmission routes of H. pylori are discussed, focusing on the five primary transmission routes, namely fecal-oral, oral-oral, gastric-oral, anal-oral, and genital-oral. We propose that H. pylori is contracted through multiple transmission routes. Additionally, we summarize the key transmission patterns of H. pylori, including person-to-person and animal-to-human transmission, as well as foodborne and occupational exposure.

CONCLUSION

Fecal-oral appears to be the most common H. pylori transmission routes. Although the oral-oral pathway is also important, the evidence does not support that this route of transmission is universal. The gastric-oral route occurs primarily in children and patients who are prone to vomiting. Meanwhile, the anal-oral and genital-oral routes remain hypothetical. Person-to-person and foodborne infections represent the predominant transmission patterns of H. pylori, whereas strong environmental and occupational limitations are associated with animal-to-human and occupational exposure.

Non-invasive diagnostic tests for Helicobacter pylori infection

BACKGROUND

Helicobacter pylori (H pylori) infection has been implicated in a number of malignancies and non-malignant conditions including peptic ulcers, non-ulcer dyspepsia, recurrent peptic ulcer bleeding, unexplained iron deficiency anaemia, idiopathic thrombocytopaenia purpura, and colorectal adenomas. The confirmatory diagnosis of H pylori is by endoscopic biopsy, followed by histopathological examination using haemotoxylin and eosin (H & E) stain or special stains such as Giemsa stain and Warthin-Starry stain. Special stains are more accurate than H & E stain. There is significant uncertainty about the diagnostic accuracy of non-invasive tests for diagnosis of H pylori.

OBJECTIVES

To compare the diagnostic accuracy of urea breath test, serology, and stool antigen test, used alone or in combination, for diagnosis of H pylori infection in symptomatic and asymptomatic people, so that eradication therapy for H pylori can be started.

SEARCH METHODS

We searched MEDLINE, Embase, the Science Citation Index and the National Institute for Health Research Health Technology Assessment Database on 4 March 2016. We screened references in the included studies to identify additional studies. We also conducted citation searches of relevant studies, most recently on 4 December 2016. We did not restrict studies by language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We included diagnostic accuracy studies that evaluated at least one of the index tests (urea breath test using isotopes such as 13C or 14C, serology and stool antigen test) against the reference standard (histopathological examination using H & E stain, special stains or immunohistochemical stain) in people suspected of having H pylori infection.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the references to identify relevant studies and independently extracted data. We assessed the methodological quality of studies using the QUADAS-2 tool. We performed meta-analysis by using the hierarchical summary receiver operating characteristic (HSROC) model to estimate and compare SROC curves. Where appropriate, we used bivariate or univariate logistic regression models to estimate summary sensitivities and specificities.

MAIN RESULTS

We included 101 studies involving 11,003 participants, of which 5839 participants (53.1%) had H pylori infection. The prevalence of H pylori infection in the studies ranged from 15.2% to 94.7%, with a median prevalence of 53.7% (interquartile range 42.0% to 66.5%). Most of the studies (57%) included participants with dyspepsia and 53 studies excluded participants who recently had proton pump inhibitors or antibiotics.There was at least an unclear risk of bias or unclear applicability concern for each study.Of the 101 studies, 15 compared the accuracy of two index tests and two studies compared the accuracy of three index tests. Thirty-four studies (4242 participants) evaluated serology; 29 studies (2988 participants) evaluated stool antigen test; 34 studies (3139 participants) evaluated urea breath test-13C; 21 studies (1810 participants) evaluated urea breath test-14C; and two studies (127 participants) evaluated urea breath test but did not report the isotope used. The thresholds used to define test positivity and the staining techniques used for histopathological examination (reference standard) varied between studies. Due to sparse data for each threshold reported, it was not possible to identify the best threshold for each test.Using data from 99 studies in an indirect test comparison, there was statistical evidence of a difference in diagnostic accuracy between urea breath test-13C, urea breath test-14C, serology and stool antigen test (P = 0.024). The diagnostic odds ratios for urea breath test-13C, urea breath test-14C, serology, and stool antigen test were 153 (95% confidence interval (CI) 73.7 to 316), 105 (95% CI 74.0 to 150), 47.4 (95% CI 25.5 to 88.1) and 45.1 (95% CI 24.2 to 84.1). The sensitivity (95% CI) estimated at a fixed specificity of 0.90 (median from studies across the four tests), was 0.94 (95% CI 0.89 to 0.97) for urea breath test-13C, 0.92 (95% CI 0.89 to 0.94) for urea breath test-14C, 0.84 (95% CI 0.74 to 0.91) for serology, and 0.83 (95% CI 0.73 to 0.90) for stool antigen test. This implies that on average, given a specificity of 0.90 and prevalence of 53.7% (median specificity and prevalence in the studies), out of 1000 people tested for H pylori infection, there will be 46 false positives (people without H pylori infection who will be diagnosed as having H pylori infection). In this hypothetical cohort, urea breath test-13C, urea breath test-14C, serology, and stool antigen test will give 30 (95% CI 15 to 58), 42 (95% CI 30 to 58), 86 (95% CI 50 to 140), and 89 (95% CI 52 to 146) false negatives respectively (people with H pylori infection for whom the diagnosis of H pylori will be missed).Direct comparisons were based on few head-to-head studies. The ratios of diagnostic odds ratios (DORs) were 0.68 (95% CI 0.12 to 3.70; P = 0.56) for urea breath test-13C versus serology (seven studies), and 0.88 (95% CI 0.14 to 5.56; P = 0.84) for urea breath test-13C versus stool antigen test (seven studies). The 95% CIs of these estimates overlap with those of the ratios of DORs from the indirect comparison. Data were limited or unavailable for meta-analysis of other direct comparisons.

AUTHORS' CONCLUSIONS

In people without a history of gastrectomy and those who have not recently had antibiotics or proton ,pump inhibitors, urea breath tests had high diagnostic accuracy while serology and stool antigen tests were less accurate for diagnosis of Helicobacter pylori infection.This is based on an indirect test comparison (with potential for bias due to confounding), as evidence from direct comparisons was limited or unavailable. The thresholds used for these tests were highly variable and we were unable to identify specific thresholds that might be useful in clinical practice.We need further comparative studies of high methodological quality to obtain more reliable evidence of relative accuracy between the tests. Such studies should be conducted prospectively in a representative spectrum of participants and clearly reported to ensure low risk of bias. Most importantly, studies should prespecify and clearly report thresholds used, and should avoid inappropriate exclusions.

The occupational risk of Helicobacter pylori infection among gastroenterologists and their assistants

BACKGROUND

Helicobacter pylori is a widely spread bacterium that mainly inhabits the gastric mucosa and can lead to serious illnesses such as peptic ulcer disease, gastric carcinoma and gastric MALT lymphoma. The oral-oral route seems to be the main transmission route. The fact that endoscopes are contaminated after being used to perform a gastroscopy leads one to question whether gastroenterologists and endoscopy nurses and assistants run a higher risk of infection.

METHODS

A systematic search for literature was conducted in the MEDLINE and EMBASE databases and further publications were found in reference lists of relevant articles. Epidemiological studies on the occupational exposure of endoscopy personnel were collected and their quality was assessed. Pooled effect estimates were identified in a meta-analysis.

RESULTS

Of the 24 studies included in the analysis, 15 were considered to be methodologically good. Of these 15 studies, eight single studies showed a statistically significant increased risk of infection for gastroenterologists, and five for their assistants. Meta-analysis across all methodologically good studies found a statistically significant risk of 1.6 (95%CI 1.3-2.0) for doctors. The pooled effect estimates also indicated a statistically significant risk of Helicobacter pylori infection (RR 1.4; 95%CI 1.1-1.8) for assistants too.When studies are stratified by medical and non-medical control groups, statistically significant risks can only be recognised in the comparison with non-medical controls.

CONCLUSIONS

In summary, our results demonstrated an increased risk of Helicobacter pylori infection among gastroenterological personnel. However, the choice of control group is important for making a valid assessment of occupational exposure risks.

Current issues in endoscope reprocessing and infection control during gastrointestinal endoscopy

The purpose of this article is to review the evidence regarding transmission of infection during gastrointestinal endoscopy, factors important in endoscope reprocessing and infection control, areas to focus on to improve compliance, and recent developments and advances in the field.

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.

Infection control during gastrointestinal endoscopy

Infection-control issues during gastrointestinal endoscopy, which are becoming increasingly important, can generally be divided into three major areas: (1) infectious complications resulting from a patient's own microbial flora (autologous), (2) infections transmitted from patient to patient by way of the endoscope (exogenous), and (3) infections transmitted between the patient and the health-care provider. The mean frequency of postprocedure bacteremia ranges from 0.5% for flexible sigmoidoscopy to 2.2% for colonoscopy, 4.2% for esophagogastroduodenoscopy, 8.9% for variceal ligation, 11% for endoscopic retrograde cholangiopancreatography, 15.4% for variceal sclerotherapy, and 22.8% for esophageal dilation. Although postprocedure bacteremia is not uncommon, it seldom results in infectious complications. Exogenous infections transmitted during endoscopy, which are extremely rare, generally result from failure to follow accepted guidelines for the cleaning and disinfection of gastrointestinal endoscopes, underscoring the importance of meticulous attention to endoscope reprocessing. Finally, although the risk of patient-staff transmission of infection is also rare, standard infection-control recommendations are important in protecting both patients and health-care providers.

Seroprevalence of Helicobacter pylori antibodies in medical students and residents in Recife, Brazil

BACKGROUND

The epidemiology of Helicobacter pylori (Hp) still constitutes a relevant subject of investigation.

GOAL

The goal of this study was to determine the seroprevalence rate of Hp antibodies in medical students and residents, and its relationship with medical practice, age, gender and parents' formal education level.

STUDY

The study was carried out from March 1999 to March 2000, on a population of 1,119 medical students and residents, from which a randomized and stratified sample was drawn. Each stratum comprised students attending the basic training level, students attending the professional training level, and residents. Independent samples were calculated for each group, making a total of 405 subjects. Each participant was interviewed using a questionnaire. After the interview, serum samples were collected and stored at -20 degrees C for detecting IgG antibodies against Hp by an enzyme-linked immunosorbent assay.

RESULTS

A 31.4% seroprevalence rate of Hp antibodies was observed, which significantly increased during the graduation course according to the medical practices, ranging from 23.4% in students up to 38.6% in residents. Seroprevalence rate increased according to the age (p = 0.002), where older individuals had spent more time in practical activities. Seroprevalence was higher in males and was smaller among those whose parents had a university degree.

CONCLUSION

The seroprevalence rate of Hp antibodies amongst medical students and residents increases from the basic up to residence level, suggesting that contact with patients during clinical practice may constitute a risk factor for acquiring Hp infection.

High risk of Helicobacter pylori infection in young Japanese dentists

BACKGROUND AND AIM

The route of person-to-person transmission of Helicobacter pylori may be either fecal-oral or oral-oral, because the bacterium is found in both dental plaque and feces. We assessed the prevalence of H. pylori seropositivity, which reflects present or past infection, in Japanese dentists exposed occupationally to dental plaque.

METHODS

We examined the sera of 60 dentists (34 who were 20-29 years or older, and 26 who were over 30 years of age) and 60 age-matched controls by using quantitative ELISA for antibodies of the immunoglobulin G class to H. pylori.

RESULTS

The proportion of dentists seropositive for H. pylori (42 of 60, 70%) was higher than in controls (23 of 60, 38%). The odds ratio for H. pylori seropositivity (3.8; 95% CI, 1.76-8.02) was high in the dentists. When dentists were classified in terms of the length of their practice, the odds ratio for seropositivity (10.4; 95% CI, 3.26-32.85) was high in the dentists practising for fewer than 4 years. The proportion of dentists in their 20s who were seropositive was greater than that in the group of age-matched controls.

CONCLUSION

Japanese young dentists are at a high risk for H. pylori infection, with the oral-oral transmission route being possibly the most common.

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.

Gut decontamination of critically ill patients reduces Helicobacter pylori acquisition by intensive care nurses

The prevalence of Helicobacter pylori is increased in healthcare workers and in intensive care nurses. Exposure to H. pylori from gastric secretions and faeces are probably the main sources of transmission to healthcare workers. Routine use of selective decontamination of digestive tract (SDD) in an intensive care unit suppresses H. pylori in critically ill patients. It was questioned whether this suppression and the subsequent decreased exposure to H. pylori for intensive care nurses would lead to a lower prevalence of H. pylori infection. Helicobacter pylori infection prevalence in intensive care nurses from a unit routinely using SDD (group I) was compared to that of nurses from a unit not using SDD (group II). Heathcare workers from other departments of the hospital where no SDD was used (group III) served as a control group. Persons using proton pump inhibitors were excluded. Helicobacter pylori was detected by Laser Assisted Ratio Analyser(13)C-urea breath test (UBT) and serology. This could not be performed in three out of 64 in group I, five out of 55 in group II and five out of 55 in group III (total UBTs = 169). The prevalence of H. pylori infection was 11% (7/61) in group I and 25.5% (14/50) in group II (P= 0.027). In group III, the prevalence of H. pylori infection was 16% (8/45), which was not significantly different from both group I and II. Sero-prevalence in group I was 18.6%, 27% in group II (ns) and 24% in group III. Mean age in the three groups was 35.9, 37.8 and 36.6 years, respectively (ns). In conclusion, the prevalence of H. pylori infection among intensive care nurses is lower in nurses from a unit using SDD compared to a non SDD-using unit. Acquisition of H. pylori by transmission from critically ill patients appears to be diminished through SDD use.

Helicobacter pylori and endoscopy

Helicobacter pylori is possibly the most common bacterial infection of humans and is now recognized as the most important acquired cause of peptic ulceration. Epidemiological evidence also recently implicated this bacterium in the pathogenesis of gastric cancer. The mechanism of spread of the organism, by either the faecal-oral or oral-oral route, raises the possibility of transmission of this organism from infected patients to hospital staff particularly those involved in endoscopy. The evidence for an increased risk to endoscopists is contradictory, varying from none to a five-fold increase. This review summarizes the evidence for mode of transmission and risk to hospital staff from this important bacterium.