Helicobacter pylori in intensive care: why we should be interested

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.

Helicobacter pylori infection is not associated with an increased hemorrhagic risk in patients in the intensive care unit

Introduction

The potential role of Helicobacter pylori in acute stress ulcer in patients in an intensive care unit (ICU) is controversial. The aim of this study was to determine the frequency of H. pylori infection in ICU patients by antigen detection on rectal swabs, and to analyze the potential relationship between the presence of H. pylori and the risk of digestive gastrointestinal bleeding.

Methods

In this prospective, multicenter, epidemiological study, the inclusion criteria were as follows: patients admitted to the 12 participating ICU for at least two days, who were free of hemorrhagic shock and did not receive more than four units of red blood cells during the day before or the first 48 hours after admission to the ICU. Rectal swabs were obtained within the first 24 hours of admission to the ICU and were tested for H. pylori antigens with the ImmunoCard STAT! HpSA kit. The following events were analyzed according to H. pylori status: gastrointestinal bleeding, unexplained decline in hematocrit, and the number of red cell transfusions.

Results

The study involved 1,776 patients. Forty-nine patients (2.8%) had clinical evidence of upper digestive bleeding. Esophagogastroduodenoscopy was performed in 7.6% of patients. Five hundred patients (28.2%) required blood transfusion. H. pylori antigen was detected in 6.3% of patients (95% confidence interval 5.2 to 7.5). H. pylori antigen positivity was associated with female sex (p < 0.05) and with a higher Simplified Acute Physiology Score II (SAPS II; p < 0.05). H. pylori antigen status was not associated with the use of fiber-optic gastroscopy, the need for red cell transfusions, or the number of red cell units infused.

Conclusion

This large study reported a small percentage of H. pylori infection detected with rectal swab sampling in ICU patients and showed that the patients infected with H. pylori had no additional risk of gastrointestinal bleeding. Thus H. pylori does not seem to have a major role in the pathogenesis of acute stress ulcer in ICU patients.

An observational study of upper gastrointestinal bleeding in intensive care units: is Helicobacter pylori the culprit?

OBJECTIVE

Upper gastrointestinal bleeding (UGIB) related to stress ulcers was formerly a fearsome complication of intensive care. The incidence of this event has decreased over the years. However, the morbidity, mortality, and causes of UGIB, particularly the etiologic role of Helicobacter pylori infection, are still controversial. Therefore, we prospectively assessed the incidence of UGIB in the intensive care unit (ICU) and evaluated the role of H. pylori infection.

DESIGN

A prospective observational study followed by a case-control study.

SETTING

Seven ICUs in the Paris area, five of them located in teaching hospitals.

PATIENTS

All patients admitted consecutively to seven ICUs during a 1-year period were monitored for signs of clinically relevant UGIB.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Only cases of endoscopically confirmed UGIB were analyzed. Patients whose hemorrhage originated from the stomach and/or duodenum were tested for H. pylori infection, by means of serology, histologic examination, and stool antigen detection. The possible association between H. pylori and UGIB was examined in a case-control study. Twenty-nine of the 4,341 patients admitted to the seven ICUs during the study period had clinically relevant, endoscopically confirmed UGIB (incidence, 0.67%; 95% confidence interval, 0.56%-0.77%). Ulcers were most frequently observed endoscopically. Patients who bled had a higher Simplified Acute Physiology Score (SAPS II) at admission (mean +/- sd, 47 +/- 14 vs. 36 +/- 28; p < .001). Despite a higher in-ICU mortality rate among patients who bled (73% vs. 16%; p < .001), death was never due to bleeding. H. pylori infection was more frequent in patients who bled than in matched controls (36% vs. 16%; p = .04).

CONCLUSIONS

Clinically relevant, endoscopically confirmed UGIB is a rare event in the ICU setting and tends to occur in severely ill patients. H. pylori infection is more frequent in patients with gastroduodenal hemorrhage than in nonbleeding patients.

Establishment of mouse models with long-term infection of H. pylori

AIM: To develop a mouse model with long-term infection of H. pylori.

METHODS: Each mouse was inoculated with H. pylori Sydney strain 1 (SS1). Noninfected control mice and infected mice were killed at 4, 12 and 24 wk after H. pylori infection. A piece of gastric mucosa obtained from the posterior wall of the antrum of each mouse was used for culture of H. pylori, rapid urease testing and histopathological detection. Serum was obtained to measure the IgG antibody level to H. pylori.

RESULTS: After 4 wk of infection, the H. pylori was cultured from 6 of 7 infected Babl/c mice and 5 of 7 the H. pylori-infected C57BL/6 mice. After 12 and 24 wk of infection, all of 7 infected Babl/c and 6 of 7 the H. pylori-infected C57BL/6 mice showed the positive results. At the different wk, the rapid urease test results were consistent with the H. pylori culture test. At 12 wk after inoculation, chronic inflammation was observed in the pyloric mucosa by histopathological examination. At 24 wk after inoculation, lymphoid follicles were especially conspicuous in the submucosa, and they were also found in the deep portion of the mucosa.

CONCLUSION: H. pylori SS1 can colonize easily in the glandular stomach mucosa of mouse, and the histopathological changes are similar to those of humans with H. pylori infection.