Gastric penetration of amoxicillin in a human Helicobacter pylori-infected xenograft model

The multicenter real-world report of the efficacies of 14-day esomeprazole-based and rabeprazole-based high-dose dual therapy in first-line Helicobacter pylori eradication in Taiwan

BACKGROUND

High-dose dual therapy (HDDT) using proton-pump inhibitors (PPI) and amoxicillin attracted attention for its simplicity and lower adverse event profile. Besides, vonoprazan is not available worldwide. This real-world study aims to compare the efficacy of esomeprazole-based and rabeprazole-based HDDT regimens and to identify clinical factors influencing outcomes.

METHODS

A retrospective study enrolled 346 Helicobacter pylori-infected naïve patients from January 2016 to August 2023. Patients were assigned to either a 14-day esomeprazole-based HDDT (EA-14; esomeprazole 40 mg t.i.d. and amoxicillin 750 mg q.i.d. for 14 days, n = 173) or a 14-day rabeprazole-based HDDT (RA-14; rabeprazole 20 mg and amoxicillin 750 mg q.i.d. for 14 days, n = 173).

RESULTS

Five patients from the EA-14 group and 10 from the RA-14 group were lost to follow-up, resulting in 168 and 163 patients for the per-protocol (PP) analysis, respectively. Eradication rates for the EA-14 and RA-14 groups were 90.2% and 80.9% (P = 0.014) in intention-to-treat (ITT) analysis; and 92.9% and 85.9% (P = 0.039) in PP analysis. Adverse event rates were similar between the two groups (11.9% vs 11.7%, P = 0.944). In multiple logistic regression analysis, age≧60 was associated with eradication failure (P = 0.046) and a trend of significance for smoking (P = 0.060) in the EA-14 group but not in the RA-14 group. A trend of significance was also observed for eradication regimens (EA-14 vs RA-14) (P = 0.071). The antibiotic resistance rates were amoxicillin (2.3%), clarithromycin (14.7%), metronidazole (40.3%), and dual resistance to clarithromycin and metronidazole (7.0%).

CONCLUSIONS

Esomeprazole-based HDDT achieved over 90% eradication rates but rabeprazole-based HDDT, which failed.

Helicobacter pylori diagnosis and therapy in the era of antimicrobial stewardship

The diagnosis and therapy of Helicobacter pylori infection have undergone major changes based on the use the principles of antimicrobial stewardship and increased availability of susceptibility profiling. H. pylori gastritis now recognized as an infectious disease, as such there is no placebo response allowing outcome to be assessed in relation to the theoretically obtainable cure rate of 100%. The recent recognition of H. pylori as an infectious disease has changed the focus to therapies optimized to reliably achieve high cure rates. Increasing antimicrobial resistance has also led to restriction of clarithromycin, levofloxacin, or metronidazole to susceptibility-based therapies. Covid-19 resulted in the almost universal availability of polymerase chain reaction testing in hospitals which can be repurposed to utilize readily available kits to provide rapid and inexpensive detection of clarithromycin resistance. In the United States, major diagnostic laboratories now offer H. pylori culture and susceptibility testing and American Molecular Laboratories offers next-generation sequencing susceptibility profiling of gastric biopsies or stools for the six commonly used antibiotics without need for endoscopy. Current treatment recommendations include (a) only use therapies that are reliably highly effective locally, (b) always perform a test-of-cure, and (c) use that data to confirm local effectiveness and share the results to inform the community regarding which therapies are effective and which are not. Empiric therapy should be restricted to those proven highly effective locally. The most common choices are 14-day bismuth quadruple therapy and rifabutin triple therapy. Prior guidelines and treatment recommendations should only be used if proven locally highly effective.

Evaluation of the benefit of addition of clidinium C to a Helicobacter pylori eradication regimen

AIM

This study aimed to evaluate the success of H.pylori eradication therapy in patients with dyspepsia by therapeutics regimes with and without clidinium C.

BACKGROUND

Helicobacter pylori infections are reported in all parts of the world. Appropriate antibiotic therapy can treat infection. The ideal treatment regimen has not been specified.

PATIENTS AND METHODS

In a randomized, double blind clinical trials study, 250 patients with dyspepsia were enrolled. All patients were treated by Omeprazole, Metronidazole, Amoxicillin and Bismuth (OMAB) for two weeks. One tablet clidinium C before each meal was added to this regimen in the intervention group (A). Urea Breath Test (UBT) was carried out after 8-12 weeks after treatment for evaluation of H.pylori eradication.

RESULTS

132 patients in the intervention group (A) and 118 patients in the control group (B) were enrolled to the study. The rate of eradication in group A was significantly higher than group B (62.1% vs. 50%, p=0.04).

CONCLUSION

The results supported the effect of clidinium C for increasing of helicobacter pylori eradication, but further studies need to be performed.

Transfer and distribution of amoxicillin in the rat gastric mucosa and gastric juice and the effects of rabeprazole

AIM

To investigate the distribution of amoxicillin in the gastric juice and gastric mucosa of rats and to investigate the effects of proton pump inhibitor rabeprazole on amoxicillin concentrations in various compartments.

METHODS

One hundred and sixty anesthetized rats were divided into five groups, and given intravenously different doses of amoxicillin or amoxicillin and rabeprazole. The pH value and volume of gastric juice was aspirated were measured and separated gastric mucosa was homogenized. The concentrations of amoxicillin in the plasma, gastric juice and gastric mucosa were measured by high performance liquid chromatography (HPLC).

RESULTS

The maximum concentrations of amoxicillin in gastric juice and gastric mucosa were significantly lower than those in plasma (P<0.001). Concentrations in the glandular stomach mucosa were higher than those in the forestomach mucosa. Rabeprazole did not significantly change the pharmacokinetic parameters of amoxicillin in the plasma and did not alter gastric antibiotic clearance or the gastric transfer fraction of amoxicillin in gastric juice. However, rabeprazole did increase the amoxicillin concentration and pH value in gastric juice and reduced the volume of the gastric juice.

CONCLUSION

Amoxicillin could penetrate the gastric mucosa and achieve therapeutic concentrations at the target site after transfer from the blood to the stomach. Rabeprazole increased the amoxicillin concentration in gastric juice by decreasing the gastric juice volume but did not affect its concentration in blood or gastric mucosa.

Breaking the species barrier: use of SCID mouse-human chimeras for the study of human infectious diseases

Mouse-human chimeras have become a novel way to model the interactions between microbial pathogens and human cells, tissues or organs. Diseases studied with human xenografts in severe combined immunodeficient (SCID) mice include Pseudomonas aeruginosa infection in cystic fibrosis, group A streptococci and impetigo, bacillary and amoebic dysentery, and AIDS. In many cases, disease in the human xenograft appears to accurately reproduce the disease in humans, providing a powerful model for identifying virulence factors, host responses to infection and the effects of specific interventions on disease. In this review, we summarize recent studies that have used mouse-human chimeras to understand the pathophysiology of specific bacterial and protozoan infections.

Impact of acid secretion, gastritis, and mucus thickness on gastric transfer of antibiotics in rats

BACKGROUND AND AIMS

The success of Helicobacter pylori eradication regimens depends on gastric pH, inflammation, and mucus thickness. Our aim was to investigate the effects of acid secretion, inflammation, and mucolysis on gastric antibiotic transfer.

SUBJECTS AND METHODS

A total of 134 anaesthetised rats were given metronidazole, amoxicillin, or clarithromycin intravenously and gastric contents were aspirated via an indwelling cannula. Acid secretion was controlled by either omeprazole or pentagastrin while gastritis was induced by infection with H pylori or dosing with iodoacetamide. Mucolysis was achieved by instilling pronase into the gastric lumen.

RESULTS

Metronidazole transfer increased with acid secretion and fell with omeprazole, independently of gastric pH. Clarithromycin was also transferred with acid but was then rapidly degraded. Omeprazole prevented this degradation, raising gastric luminal concentrations. Omeprazole did not alter amoxicillin transfer. Gastritis induced by H pylori did not alter gastric transfer of metronidazole and amoxicillin but that of clarithromycin was increased by 23%. However, gastritis induced by iodoacetamide reduced clarithromycin transfer without any effect on metronidazole or amoxicillin transfer. Pronase treatment increased amoxicillin transfer fourfold and metronidazole by 66% but reduced clarithromycin transfer by 35%.

CONCLUSIONS

Metronidazole and clarithromycin are predominantly transferred with gastric acid rather than by an acid trapping mechanism. Pronase increases the appearance of amoxicillin and metronidazole in gastric secretions.