الفهرس 
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Abstract
Gastric organisms which were 1st observed more than 100 years ago and their association with gastritis has been recognized since 1970s. The true implication of these microbes was not fully realized, however until 1982 when Marshall and warren identified and subsequently cultured the bacterium campylobacter pylori later reclassified as H. pylori.
H. pylori is a spiral shaped, slow growing, microaerophilic gram negative bacterium measuring 3.5 micron in length and 0.5 micron in width .It is a slow growing organism that can be cultured on blood agar or selective media such as skirrow’s media, incubated at 37C˚ in 5% oxygen atmosphere for 3 to 7 days.
The organism can be morphologically characterized by gram stain and their typical spiral or rod shaped appearanc.High power microscopy reveals that the organism has two to seven unipolar sheathed flagellae which enhance its motility through viscous solutions.It is biochemically characterized as catalase, oxidase and urease positive
H. pylori are the most common chronic bacterial infection in humans. Conservative estimates suggest that 50 percent of the world’s population is affected .Infection is more frequent in develolping countries compared with industrialized nations.The risk of infection acquisition is related to socioeconomic status and living conditions early in life.
Transmission of H. pylori is still not entirely clarified. Human to human spread through oral-oral or fecal –oral route is thought to be
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the most plausible.Once infection is acquired, it generally persists in absence of antibiotic treatment.
Certain Helicobacter pylori virulence factors and host genetic polymorphism are known to affect the clinical outcome of H. pyloriinfection.Functional differences of different H.pylori strains lead to virulence differences. Strains producing Vac A and CagA cause more intense tissue inflammation and cytokine production
The life time risk of H. pylori related disease is less than 20 percent. Up to 85 percent of infected individuals never experience symptoms or complications. Individuals infected with H. pylori have approximately 10 percent life time risk of developing peptic ulcer, 1-3 percent risk of acquiring gastric adenocarcinoma and less than 0.1 percent to develop gastric mucosa associated lymphoid tissue lymphoma.
Currently test-and-treat strategy is appropriate for uninvestigated dyspepsia in high prevalence populations.This approach is subject to local cost benefit considerations and not applicable to patients with alarm symptoms, or older patients. Recurrent abdominal pain (RAP) is not an indication for a test and treatment strategy
H.pylori role in some hematologic conditions such as iron deficiency anaemia,immune thrombocytopaenicpurpura and vit B12 deficiency has been fully validated and included in the current guidelines.
Further studies are still needed to evaluate the role of H. pylori in other diseases such as growth retardation in children, asthma and other allergic disorders..
Diagnosis of H.pylori infection is indicated in patients with active peptic ulcer or past history of documented ulcer, gastric MALT lymphoma, pathologically proven gastric atrophy, metaplasia and gastric adenocarcinoma. Test and treat strategy is indicated for uninvestigated dyspepsia under age of 55 with no alarm signs.
Other indications for H.pylori diagnosis include asymptomatic individuals with a family history of gastric cancer, patients on long term PPIs, prior to long treatment with NSAIDs, in ITP, unexplained or refractory IDA and vitamin B12 deficiency.
Diagnostic methods to detect H. pylori infection are diverse and classified as:
1- Invasive tests includingrapid or biopsy urease test, histology and bacterial culture and sensitivity
2- Non-invasivetestsincluding ureabreath test, stool antigen test and serology.
Choice of one method or another depends on several factors, such as the availability of diagnostic tests, need to perform an endoscopy, cost, accessibility, advantages and disadvantages of each method and age of patient.
PPIs or antibiotics should be stopped at least two and four weeks respectively before testing by culture , histology , rapid urease test , urea breath test (UBT),or stool antigen test (SAT). If it’s not possible validated IgG can be performed.
UBT is the most commonly used non- invasive test for children although it has some limitations in children under five years.The diagnostic accuracy of (SAT) is equivalent to UBT, if a validated laboratory based monoclonal test is used. Serological tests can’t be used alone to diagnose H. pylori infection or for follow up for eradication .
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H. pylori testing should be offered to all patients after eradication therapy.Every patient with ulcer disease, patient treated for non – invasive gastric cancer and patient with MALT lymphoma must be tested after eradication to ensure successful eradication.
The optimal time to test for eradication therapy success should be at least 4 weeks after the end of therapy.Urea breath test, monoclonalfecal antigen test, rapid urease test and histology of gastric biopsies can be used to check eradication.
The goal of H. pylori treatment is complete elimination of the organism. Once this is achieved, re-infection rates are low, thus the benefit of treatment is durable.The main reasons for eradication failure of H. pylori infection include antibiotic resistance, poor compliance and rapid metabolism of PPIs.Triple therapy is the standard most frequently used strategyfor treatment.It should be abandoned in areas of clarithromycin resistance
With rising prevalence of anti -microbial resistance of H. pylori, the success rate of the standard triple therapy has recently declined to unacceptable levels in most countries therefore; several new treatment regimens have been evaluated for H. pylori eradication.
Novel first-line anti-H.pylori regimens include sequential therapy, concomitant quadruple therapy, hybrid (dual-concomitant) therapy and bismuth-containing quadruple therapy.
In areas of high clarithromycin resistance, bismuth containing quadruple treatments are recommended for first line empirical treatment. IF this regimen is not available sequential treatment or non bismuth quadruple treatment is recommended
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After failure of standard triple therapy, a bismuth-containing quadruple therapy comprising a proton pump inhibitor (PPI), bismuth, tetracycline and metronidazole can be employed as a rescue treatment.
Recently, triple therapy combining a PPI, levofloxacin and amoxicillin has been proposed as an alternative to the standard rescue therapy.This regimen can be used as second line therapy for patients who fail to eradicate H. pylori with new first line therapies such as sequential, concomitant or hybrid therapy remains unclear
Patients requiring third-line therapy should be referred to a medical center and treated according to the antibiotic susceptibility test. Alternatively, an empirical therapy such as levofloxacin-based or furazolidone-based therapies can be employed to terminate H.pylori infection if antimicrobial sensitivity data are unavailable.
Certain probiotic and prebiotics show promising results as an adjuvant treatment. It reduces side effects of the therapeutic drugs and increases the eradication success rate of different regimens.