الفهرس 
H. pylori morphologyOnly 14 pages are availabe for public view
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Abstract
Helicobacter pylori (H. pylori), one of the most common bacterial pathogens in the world, is an important global health concern. (1) This organism infects approximately one half of the world’s population. (2) The prevalence varies greatly between countries and between population groups within the same country and is inversely associated with socioeconomic status or household hygiene and sanitation. (3) In developing countries, more than 80% of the population is H. pylori positive, even at young ages, while in developed countries the prevalence generally remains under 40% and is considerably lower in children and adolescents than in adults and elderly people. (4)
H. pylori infection is commonly acquired in childhood. (5) The prevalence of infection among children ranges from 2.4 to 13.6% in developed countries and from 22.6 to 80% in developing countries. This difference may be attributed to poor socioeconomic status and overcrowded conditions during childhood. (6)In Egypt, infection is alarmingly high. (7) A prevalence rate of 33% has been reported among children less than 6 years and 72.38% among school children. (8)
As the human stomach is the only identified reservoir, it has been speculated that person-to-person spread appeared to be the most likely mode of transmission especially between family members. (9, 10) Hence, the possible routes are feco–oral, oral–oral and gastro– oral. (11)
Transmission events were more frequent between close relatives and between individuals living in the same house. (12) It is indicated that mothers play the key role in transmission of H. pylori to their children and spouses.(13)
Although H. pylori cause some degree of persistent inflammation, the majority of people have no symptoms and a large number of infections may go undiagnosed. (14) Symptoms of H. pylori are nonspecific in children and may include epigastric pain, nausea and/or vomiting, anorexia, iron deficiency anemia and hematemesis. (15) However, gastric colonization with H. pylori can lead to variety of upper gastrointestinal disorders, such as chronic gastritis, peptic ulcer disease, gastric mucosa- associated lymphoid tissue (MALT) lymphoma, and gastric cancer. (16)
The diagnosis of H. pylori can be done with invasive and non-invasive methods. Invasive methods need endoscopy and biopsy [histological examination, rapid urease test (RUT), culture, polymerase chain reaction (PCR), and fluorescent in situ hybridization (FISH)]. Non-invasive methods include 13C,14C urea breath test (UBT), detection ofH. pylori antigen (Ag) in stool, and detection of antibodies (Abs) against H. pylori in serum, urine, and saliva. (17, 18)
Invasive methods, such as endoscopy with biopsies and / or urease tests used to be the gold standard for detection of H. pylori. These are time consuming methods and are not suitable for children less than 6 years. (17) Non-invasive tests for H. pylori infection have been helpful in epidemiological studies of prevalence, mode of transmission and spontaneous clearance of the infection. Their main advantages over invasive tests are their simplicity, low cost, speed, and minimal patient discomfort.(19)
Considering the broad spectrum of available H. pyloridiagnostic methodsand sincea reliable diagnosis is mandatory both before and after eradication therapy;thusit iscrucial to study the different methods to be able to select thehighly accurate laboratory tests that could be used toefficiently diagnose H. pylori infection in clinical practice.