False about H. pylori is
|A||Grows best in anaerobic conditions|
|B||Most definitive test is urea breath test|
|C||Modified Giemsa stain is used for visualization|
|D||H. pylori is major risk factor for primary gastric non-Hodgkin's lymphoma|
a. The bacterium, initially named Campylobacter pyloridis, is a gram-negative microaerophilic rod found most commonly in the deeper portions of the mucous gel coating the gastric mucosa or between the mucous layer and the gastric epithelium.
b. It may attach to gastric epithelium but under normal circumstances does not appear to invade cells.
c. It is strategically designed to live within the aggressive environment of the stomach. It is S-shaped (~0.5 x 3 m in size) and contains multiple sheathed flagella.
d. Initially, H. pylori resides in the antrum but, over time, migrates toward the more proximal segments of the stomach. The organism is capable of transforming into a coccoid form, which represents a dormant state that may facilitate survival in adverse conditions.
e. The genome of H. pylori (1.65 million base pairs) encodes ~1500 proteins.
f. Among this multitude of proteins there are factors that are essential determinants of H. pylori–mediated pathogenesis and colonization, such as the outer membrane protein (Hop proteins), urease, and the vacuolating cytotoxin (Vac A).
g. Moreover, the majority of H. pylori strains contain a genomic fragment that encodes the cag pathogenicity island (cag-PAI).
h. Several of the genes that make up cag-PAI encode components of a type IV secretion island that translocates Cag A into host cells.
i. H. pylori infection is virtually always associated with a chronic active gastritis, but only 10–15% of infected individuals develop frank peptic ulceration.
j. The basis for this difference is unknown. Initial studies suggested that >90% of all DUs were associated with H. pylori, but H. pylori is present in only 30–60% of individuals with GUs and 50–70% of patients with DUs.