الفهرس 
Introduction and Aim of the workOnly 14 pages are availabe for public view
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Abstract
Recent studies about H. pylori infection worldwide have shown that bacterium spreading is still ongoing [315]. More than 50% of people worldwide are thought to carry H. pylori in their upper gastrointestinal tracts, according to evidence. [60]. In Egypt, there is a lack of published evidence on prevalence of H. pylori, which is approximately ranged from 70% to 80% [296].
In order to accurately diagnose H. pylori infection, gastric biopsy specimens must be examined via an upper gastrointestinal endoscope to directly identify the bacteria. [193]. However, invasive techniques including culture, histological inspection, fast urease test, and biopsy-based molecular testing are affected by the location, quantity, and size of biopsy specimens. [316]. In addition, these methods have other limitations including high cost and require trained personnel and properly equipped facilities. Consequently, the invasive biopsy-based methods aren`t reliable for follow-up of treated patients.
Noninvasive tests can be performed on serum, saliva or urine for antibody detection, on stool or saliva for antigen detection or on breath sample indicating bacterium urease activity [317]. These tests have been shown to be efficacious for diagnosis and screening of H. pylori infection with good validation when compared with culture on gastric biopsies and then offer an alternative reliable diagnostic approach for assessment of cure after treatment of infected patients [304].
Accordingly, Attallah et al. created a delicate and accurate noninvasive ELISA based on the detection of H. pylori circulating antigen (HpCA) in serum samples from H. pylori-infected people [24]. However, research on the eradication therapy efficacy has not been conducted and the assessment of cure after treatment of H. pylori infection using serum HpCA remains an elusive goal. Here, we aimed to evaluate the reliability of HpCA quantitation in human serum using ELISA for noninvasive screening and assessment of cure after triple therapy regimen of H. pylori infection in Egyptian patients.
The present study population consisted of 134 symptomatic individuals (83 males and 51 females, aged 23 - 68 years) selected from patients referred to outpatient clinics of Gastrointestinal Surgery Center (GISC), Faculty of Medicine, Mansoura University during the period August 2018 to January 2020 and underwent upper gastrointestinal endoscopy and biopsy for dyspepsia. Four biopsy specimens were taken from the antrum: two for histopathology and histological staining with hematoxylin and eosin (H & E) and Giemsa stain, one for rapid urease test and one for H. pylori culture testing.
A total of 87 (65 %) out of 134 screened individuals showed positive RUT result and 47 (35 %) showed negative RUT result. A total of 71 (53 %) out of 134 screened individuals showed positive H. pylori Giemsa staining result and 63 (47 %) showed negative H. pylori staining.
According cutlur testing as the gold standard for diagnosis, 90 (67.2 %) out of 134 screened individuals were diagnosed H. pylori infected whereas 44 (22.8 %) individuals were diagnosed free of H. pylori infection. A total of 28 (31%) out of 90 isolates showed resistant to one or both of these two antibiotics in study treatment regimen. All these individuals showing drug resistance were excluded and subjected to another study treatment protocol. The remaining 62 (69 %) out of 90 isolates showed sensitivity for these two antibiotics and hence their patients were eligible for inclusion in the treatment protocol.
Blood samples were obtained from each individual before and after end of treatment protocol. Sera were separated and tested for the HpCAg using ELISA. The diagnostic potential of HpCAg-ELISA test in comparison with gold standard results in 134 Egyptian patients was investigated using ROC curve analysis. The area under the ROC curve equals 0.932 indicating high diagnostic potential of ELISA test for the detection of H. pylori infection. The performance characteristics of HpCAg-ELISA test in comparison with gold standard results showed a sensitivity of 94 %, specificity of 88 % and a total efficiency of 92 %.
In addition, a highly significant difference (p < 0.001) was shown between the mean serum concentration (± SE) of HpCAg in screened individuals with H. pylori infection (86.83 ± 2.86 g/mL) and that of screened individuals without H. pylori infection (22.45 ± 3.06 g/mL). The presence of HpCAg was significantly (p < 0.01) associated with endoscopic findings including gastric disorders (G and GU) and duodenum disorders (D and DU) in comparison with non-infected screened individuals. Also, the presence of HpCAg was significantly (p < 0.01) associated with the different pathological disorders including CSG, CDG, CAG and IM as well as with the severity of gastritis in comparison with non-infected individuals.
It is advised that all patients who have a confirmed H. pylori infection receive the proper antimicrobial care [187]. Due to the emergence of antibiotic resistance strains during the past ten years, it has been demonstrated that antimicrobial therapy is not always totally successful against H. pylori infection. [304]. Hence, clinicians’ may wish to determine if the patients have been cured of H. pylori after treatment [286].
A total of 62 patients with confirmed H. pylori infection i.e. showing positive results by using both microbiological culture and HpCAg-ELISA and showing no resistance to any of the suggested drugs were eligible and subjected to proton pump inhibitor (PPI)-based triple therapy and follow-up. Six weeks after end of eradication treatment, all individuals were referred to laboratory for repeating HpCAg testing using ELISA to evaluate to evaluate the outcome of treatment. Only 50 out of 62 treated patients provide serum samples for the detection of HpCAg using ELISA at the end of the treatment protocol. Consequently, the data of these 12 individuals were excluded from further analysis. Before treatment, the mean of HpCAg concentrations (± SE) of 50 treated individuals was 92.08 ± 3.08 g/mL and after treatment it was 24.00 ± 2.34 g/mL. In addition, a highly significant decrease (p < 0.001) was shown in HpCAg concentrations after treatment.
After treatment, 39 (78 %) out of 50 treated individuals showed HpCAg negative result (i.e. responders to treatment) and 11 (22 %) showed HpCAg positive result (i.e. non-responders to treatment). The HpCAg concentrations (15.77 ± 0.58 g/mL) of responders were significantly decreased (p < 0.005) in comparison with their HpCAg concentrations before treatment (87.90 ± 3.35 g/mL). Also, the HpCAg concentrations (53.18 ± 2.91) of non-responders were significantly decreased (p < 0.005) in comparison with their HpCAg concentrations before treatment (106.91 ± 5.69 g/mL). The eradication rate (78 %) achieved in the present study using standard Clarithromycin triple therapy is higher than that reported in other studies [318]. This may due the exclusion of all patients showing antibiotic resistance in H. pylori susceptibility testing. Notably, the current literature also shows that sensitivity-guided therapy is more effective than concomitant therapy as well [311].
Before treatment, signs and symptoms of H. pylori infection were recorded for all treated individuals. At the end of treatment protocol, no signs and symptoms of H. pylori infection were recorded for all 39 responders showing HpCAg negative result and for 4 out of 11 non-responders showing HpCAg positive result. Only 7 out of 11 non-responders still having abdominal discomfort as well as dyspeptic symptoms associated with H. pylori infection.
In conclusion, the HpCAg detection is a reproducible approach for noninvasive diagnosis and screening of H. pylori infection. Furthermore, this test can be used to prove the elimination of gastric H. pylori especially in developing countries. However, the sample size of our study was low and further large population and multi-central follow up studies are still needed to further validate the HpCAg-ELISA test results.